Attack of the Desert Snail Monsters

Q. Do you have any idea how to get rid of snails? I have a factory! There are literally hundreds throughout my grass andplanters. They are very small and we rarely see the large ones so not sure if they are regular snails or what. But I’d like to get rid of them because they grab onto the kids shoes which can bring them in the house.

Picture of the snail culprit from the reader.
Out, out, dam ned snail!

A. Snails are not usually a huge problem here due to our lack of moisture and sparse plant growth. However in a garden situation where there is plenty of water and debris on the ground they can get established, usually being brought in on nursery or garden materials.

The basic strategy is to minimize water by using drip irrigation whenever you can and clean up ground debris to remove hiding and egg laying places. Traps can be put out which is basically used so that you have some central locations where you can find them and kill them.

Usually once you get these traps established and conduct raids daily for about two weeks you will lower their numbers substantially. Then once or twice a week is all that is necessary to maintain lower numbers.

There are some devices such as copper barriers and diatomaceous earth that can be used to keep them out of specific places. Then there are the chemical baits containing metaldehyde and Sevin, an insecticide.

The following I copied verbatim from the University of California IPM website a couple of months ago. But check to make sure the information is current at their website located at

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7427.html

Snails and slugs are among the most bothersome pests in many gardens and landscapes. The brown garden snail, Cornu aspersum (formerly Helix aspersa), is the most common snail causing problems in California gardens. It was introduced from France during the 1850s for use as food. Another troublesome snail is the white garden snail, Theba pisana. It currently is established only in San Diego County but has been found in Los Angeles and Orange counties as well.


Several species of slugs also cause damage including the gray garden slug (Deroceras reticulatum,formerly Agriolimax meticulatus), the banded slug (Lehmannia poirieri), the three-band garden slug (L. valentiana), the tawny slug (Limacus flavus), and the greenhouse slug (Milax gagates).

IDENTIFICATION AND BIOLOGY

Both snails and slugs are members of the mollusk phylum and are similar in structure and biology, except slugs lack the snail’s external, spiral shell. These mollusks move by gliding along on a muscular “foot.” This muscle constantly secretes mucus, which facilitates their movement and later dries to form the silvery “slime trail” that signals the presence of either pest.

All land slugs and snails are hermaphrodites, so all have the potential to lay eggs. Adult brown garden snails lay an average of 80 spherical, pearly white eggs at a time into a hole in the soil. They can lay eggs up to 6 times a year, and it takes about 2 years for snails to mature. Slugs reach maturity after about 3 to 6 months, depending on the species, and lay clear, oval to round eggs in batches of 3 to 40 beneath leaves, in soil cracks, and in other protected areas.

Snails and slugs are most active at night and on cloudy or foggy days. On sunny days they seek hiding places out of the heat and bright light. Often the only clues to their presence are their silvery trails and plant damage. In areas with mild winters, such as southern coastal locations, snails and slugs can be active throughout the year.

During cold weather, snails and slugs hibernate in the topsoil. During hot, dry periods or when it is cold, snails seal themselves off with a parchmentlike membrane and often attach themselves to tree trunks, fences, or walls.

DAMAGE

Snails and slugs feed on a variety of living plants and on decaying plant matter. They chew irregular holes with smooth edges in leaves and flowers and can clip succulent plant parts. They also can chew fruit and young plant bark.

Because they prefer succulent foliage or flowers, they primarily are pests of seedlings and herbaceous plants, but they also are serious pests of ripening fruits that are close to the ground such as strawberries, artichokes, and tomatoes. They also will feed on foliage and fruit of some trees; citrus are especially susceptible to damage. Look for the silvery mucous trails to confirm slugs or snails caused the damage and not earwigs, caterpillars, or other chewing insects.

MANAGEMENT

A good snail and slug management program relies on a combination of methods. The first step is to eliminate, as much as possible, all places where they can hide during the day. Boards, stones, debris, weedy areas around tree trunks, leafy branches growing close to the ground, and dense ground covers such as ivy are ideal sheltering spots. It won’t be possible to eliminate some shelters such as low ledges on fences, the undersides of wooden decks, and water meter boxes, so make a regular practice of trapping and removing snails and slugs from these areas.

Locate vegetable gardens or susceptible plants as far away from snail and slug hiding places as possible. Reducing hiding places allows fewer snails and slugs to survive. The survivors congregate in the remaining shelters, where you can more easily locate and remove them.

Switching from sprinkler irrigation to drip irrigation will reduce humidity and moist surfaces, making the habitat less favorable for these pests. Choose snail-proof plants, such as those listed below, for areas where snails and slugs are dense. Copper barriers can be useful for protecting especially susceptible plants. Though baits can be part of a management program, it is better to use them in conjunction with other habitat modification, especially in gardens that contain plenty of shelter, food, and moisture.

Plant selection can greatly affect how difficult your battle with snails and slugs will be. Because snails and slugs favor seedlings and plants with succulent foliage, you will need to vigilantly protect these. Some plants these pests will seriously damage include basil, beans, cabbage, dahlia, delphinium, hosta, lettuce, marigolds, strawberries, and many other vegetable plants. On the other hand, many plants resist snail and slug damage including begonias, California poppy, fuchias, geraniums, impatiens, lantana, nasturtiums, and purple robe cup flower as well as many plants with stiff leaves and highly scented foliage such as lavender, rosemary, and sage. Most ornamental, woody plants, and ornamental grasses also aren’t seriously affected. If you design your landscape using snail and slug resistant plants, you are likely to have very limited damage.

Handpicking

Handpicking can be very effective if done thoroughly on a regular basis. At first you should look for snails and slugs daily, paying careful attention to potential hiding places. After the population has noticeably declined, a weekly handpicking can be sufficient.

To draw out snails and slugs, water the infested area in the late afternoon. After dark, search them out using a flashlight, pick them up (rubber gloves are handy when slugs are involved), place them in a plastic bag, and dispose of them in the trash. You also can put them in a bucket with soapy water and dispose of them in your compost pile after they are dead. Alternatively, crush captured snails and slugs and leave them in the garden. Another option for killing slugs you have collected is to spray them with a solution of household ammonia diluted to a 5 to 10% solution in water.

Traps

You can trap snails and slugs beneath boards or flower pots that you position throughout the garden and landscape. Inverted melon rinds also make good traps. Construct wooden traps using 12- by 15-inch boards (or any easy-to-handle size) raised off the ground by 1-inch runners. The runners make it easy for the pests to crawl underneath. Scrape off the accumulated snails and slugs daily and destroy them; crushing is the most common method. Don’t use salt to destroy snails and slugs, since it will increase soil salinity.

Some people use beer-baited traps buried at ground level to catch and drown slugs and snails that fall into them. Because it is the fermented part of the product that attracts these pests, you also can use a sugar-water and yeast mixture instead of beer. However, these traps aren’t very effective for the labor involved. Beer traps attract slugs and snails within an area of only a few feet, and you must replenish the bait every few days to keep the level deep enough to drown the mollusks. Traps must have deep, vertical sides to keep the snails and slugs from crawling out and a top to reduce evaporation. You can purchase this type of snail and slug trap at garden supply stores.

Barriers

Several types of barriers will keep snails and slugs out of planting beds. The easiest to maintain are those made with copper flashing and screen. It is believed that copper barriers are effective because the copper reacts with the slime that snails and slugs secrete, causing a disruption in their nervous system similar to an electric shock. When erecting vertical copper screens, it is best to use ones that are at least 4 inches tall, so you can bury a portion of it a few inches below the soil to prevent slugs from crawling beneath the barrier.

Copper foil (e.g. Snail-Barr) wrapped around planting boxes, headers, or trunks will repel snails for several years. When banding trunks, wrap the copper foil around the trunk, tab side down, and cut it to allow an 8-inch overlap. Attach one end or the middle of the band to the trunk with one staple oriented parallel to the trunk. Overlap and fasten the ends with one or two large paper clips to allow the copper band to slide as the trunk grows. Bend the tabs out at a 90° angle from the trunk. If the bands tarnish, you can clean them with a vinegar solution.

When using copper bands on planter boxes, be sure the soil within the boxes is snail free before applying them. If it isn’t, handpick the snails and slugs from the soil after applying the band (but before planting new plants) until the box is free of these pests. Solarizing the soil—a technique that uses clear, plastic tarp and the sun’s heat—is a good way to kill eggs in raised beds.

Instead of copper bands, Bordeaux mixture (a copper sulfate and hydrated lime mixture) or copper sulfate alone brushed onto trunks will repel snails. One treatment should last about a year. Adding a commercial spreader or white latex paint can help the Bordeaux mixture remain effective for two seasons.

Barriers of dry ashes or other abrasives heaped in a band 1 inch high and 3 inches wide around the garden also can be effective. However, these barriers lose their effectiveness after becoming damp, making them difficult to maintain and not very useful in most garden situations.

Natural Enemies

Snails and slugs have many natural enemies including ground beetles, pathogens, snakes, toads, turtles, and birds, but most are rarely effective enough to provide satisfactory control in the garden. One predator found in some California gardens is a large Staphylinid beetle called the devil’s coach horse, Ocypus olens. However, this beetle, which is more than 1-inch long, also will feed on ripening or decaying fruits and vegetables.

Domesticated fowl—such as ducks, geese, or chickens—kept penned in infested areas can be effective snail predators that significantly reduce problems. Be careful, though, as these birds also can eat seedlings.

The predatory decollate snail, Rumina decollata, has been released in Southern California citrus orchards to control young brown garden snails and is providing very effective biological control. It feeds only on small snails, not full-sized ones. Because of the potential impact of the decollate snail on certain endangered mollusk species, it can’t be released in California outside of Fresno, Imperial, Kern, Los Angeles, Madera, Orange, Riverside, Santa Barbara, San Bernardino, San Diego, Ventura, and Tulare counties. Decollate snails can feed on seedlings, small plants, and flowers and can be a nuisance when they cover the back patio on a misty day. Because snail baits will kill decollate snails, you shouldn’t use them where these predators are active.

Baits

Snail and slug baits can be effective when used properly in conjunction with a cultural program incorporating the other methods discussed above. However, baits alone won’t effectively control snails or slugs. Baits are toxic to all snails and slugs, including the predatory decollate snail and native species.

Several types of snail and slug bait products are available. Baits containing the active ingredient metaldehyde are most common; however, metaldehyde baits are particularly poisonous to dogs and cats, and the pelleted form is especially attractive to dogs. Don’t use metaldehyde snail baits where children and pets could encounter them. Metaldehyde baits containing 4% active ingredient are more effective than those containing only 2%; however, they also are more toxic to dogs and wildlife. Avoid getting metaldehyde bait on plants, especially vegetables.

Some metaldehyde products are formulated with carbaryl, partly to increase the spectrum of pests controlled such as soil- and debris-dwelling insects, spiders, and sowbugs. However, carbaryl is toxic to earthworms and soil-inhabiting beneficial insects such as ground beetles, so it is better to avoid using snail baits containing carbaryl.

Baits containing only metaldehyde are most reliable when temperatures are warm or during periods of lower humidity. When it is sunny or hot, these baits cause snails and slugs to die from desiccation or dehydration. The pests usually die with one day of ingesting the chemical or getting it on their foot. If cool, wet weather follows the baiting, they can recover if they ingest a sublethal dose. Don’t water heavily for at least 3 or 4 days after bait placement, since watering will reduce effectiveness. Most metaldehyde baits break down rapidly when exposed to sunlight and high irrigation; however, some paste or bullet formulations (e.g. Deadline) hold up somewhat longer in these conditions.

Iron phosphate baits—available under many trade names including Sluggo and Escar-Go—have the advantage of being safe for use around children, domestic animals, birds, fish, and other wildlife, making them a good choice for an integrated pest management program in your garden. Ingesting even small amounts of the bait will cause snails and slugs to stop feeding, although it can take several days for the snails to die. You can scatter the bait on lawns or on the soil around any vegetable, ornamental, or fruit tree that needs protection. Iron phosphate baits can be more effective against snails than slugs overall and more effective than metaldehyde during periods of higher humidity. Snails and slugs tend to hide before they die, so you won’t see scattered empty shells or dead snails and slugs as you would if treating them with metaldehyde.

Sprinkle baits in areas that snails and slugs regularly frequent such as around sprinkler heads. Placing baits repeatedly in the same areas maximizes control, because mollusks tend to return to food source sites. Never pile bait in mounds or clumps, especially those products that are more hazardous, because piling makes bait attractive to pets and children and is not as effective as sprinkling. Thick, liquid baits might persist better when it is rainy or in areas that receive sprinkler irrigation.

The timing of any baiting is critical; baiting is less effective during very hot, very dry, or cold times of the year, because snails and slugs are less active during these periods. Irrigate before applying a bait to promote snail activity, and apply the bait in the late afternoon or evening. Sprinkle bait around sprinklers, close to walls and fences, or in other moist and protected locations, or scatter it along areas that snails and slugs cross to get from sheltered areas to the garden.

Drip Emitters Can Plug Easily If You Are Not Careful

Pvc glue plugging an irrigation bubbler
after a repair

Q. A few years ago I had a bubbler system installed to water my trees for my desert landscaping. They did not do a good great job. It has gotten plugged a few times and the trees do not get enough water. I have gone through four trees and maybe another. Would you give me some names of trees that are truly drought resistant?

A. I hesitate giving you suggestions on plants because that is a highly subjective decision and secondly without a reliable irrigation system nothing will work in our desert except maybe Joshua trees. Besides, in our desert there are no ornamental and shade trees that will survive or look good without a good irrigation system.

Y filter for drip irrigation



Salt accumulation on a drip emitter



Make sure your irrigation system has a 150 to 200 mesh filter installed somewhere before the water reaches the emitters. This will reduce plugging. Make sure that when you or anyone repairs a drip system that they DO NOT use a pipe cutting device that rips the piping. So do not use a hacksaw or other pipe cutter that uses teeth to rip at the pipe. This will leave pipe debris in the lines that will (guaranteed) plug your emitters.

PVC cutter that does not leave debris in the pipes

Use only a cutting device that has an unserrated knife edge that cuts the piping. Use pipe cutters instead. They are more expensive but will actually work quite well. I don’t care how careful you think you are, don’t use devices that rip or shred on any part of a drip system. Once you have a reliable irrigation system then you can plant some good stuff.

Lawns Brown Spots Can Be Dogs and Poor Sprinkler Coverage

Dog urine damage leaves a dark green edge
around the damaged brown spot caused by the urine

Most likely there is a popup sprinkler in the center of that
green patch surrounded by bare soil. It is most likely
a two inch popup when a four inch is needed in tall fescue

Q. My lawn was sodded with tall fescue lawn grass a few years back and this past fall noticed I still have two problems. The pictures attached. The first are five to ten inch circles which are brown in the center with very dark green grass around it. The second are areas around the edge where there is a patch of dark green grass and then 10-15 inches of bare ground around it. I am really hoping you can provide an explanation and solution to resolve these.


A. The third picture, brown ten inch circles with dark green on the outside, looks like damage from a urinating dog. Urine results in a small round brown area where the grass is darker green around the dead spot. Readers can see these pictures by following my blog at http://www.xtremehorticulture.blogspot.com/

Popup sprinklers need clearance over the grass
if they are going to cover the lawn area evenly

The urine is too high in salts (urea, a salt high in nitrogen) and burns the immediate area around where it is applied. As the urea moves into the surrounding soil it becomes more dilute, reducing the burning, and then acts like a fertilizer high in nitrogen. Nitrogen fertilizers turn grass a dark green.

The other picture with 10 to 15 inches of bare ground around a green area, looks like the sprinkler head is in the center of that small green area next to the curb. If that is the case, I am guessing the popup is not “popping” high enough. Make sure it pops up all the way and is not getting blocked. Make sure your irrigation sprinklers are 4 inch and not 2 inch popups. Two inch popups do not pop up high enough to spray evenly above the top of a grass mowed at two inches in height. The grass height interferes with the water spray.

Pressure regulator

Also check your water pressure. It should be in the 40 to 50 psi range for most popups. If it is a lot higher than this, then your sprinklers are probably “fogging” and not delivering the right sized droplets to get even coverage over the lawn. Install a pressure regulator to drop the water pressure in the appropriate range recommended by the irrigation manufacturer for the sprinklers and nozzles.

Your tall fescue does not look very luxurious in general. It would improve from some good lawn management practices. Tall fescue is best if mowed no shorter than 1½ inch, and 2 inches is even better. Use a mulching mower and return the clippings to the lawn; don’t bag them and leave them for the garbage.

Roots of turfgrass grow easily into holes punched in
the lawn by an aerifier

Try aerating the lawn any time of the year and follow this with an application of a good quality lawn fertilizer. If you are returning the clippings to the lawn then fertilize Labor Day, Memorial Day and 4th of July. Be sure you also make an application around Thanksgiving to keep your lawn dark green through the winter months.

Lack of Cucumbers Leaves Gardener in a Pickle



Armenian Cucumber

 Q. I live in Las Vegas and want to grow baby cucumbers for pickling. I tried to grow some last Spring but was not successful. I didn't realize until the plants were about 1ft tall that I was supposed to thin them out. I did thin them but it may have been too late. The plants looked good and grew well but when they began to flower, the little tiny cucumbers got very dry and hard and shriveled up.


The pot was getting full sun most of the afternoon so my husband built an open lattice over the top for some light shade. As the later part of June approached the plants were not looking good and I gave them up, with the intention of trying again, maybe in the fall when it's cooler? I was so looking forward to growing and pickling my own.

A. Cucumbers have a fairly narrow time for production here as it gets too hot, from about late March or early April to about June. They can suffer from chilling damage if temperatures get below about 50F.

You can plant again in September since they have a fairly short production time, about 60 days. Soils should be well composted and fertilized before planting. No lack of water for these plants or you will have problems. Soils must be kept moist so cover the soil with straw mulch or other mulch you can till or spade in afterwards.

You will have less waste if you trellis them rather than letting them lay on the soil. In the warm times you will pick three times a week. The easiest to grow is Armenian cucumber but will not make very good pickles. Others to try for pickles might be Eureka and Valispik. Other vegetables and even fruit make great pickles as well.

Italian Cypress Browning Not a Good Sign

Q. Help! My Italian cypress are drying out and dying mostly from the top down and they have their own bubblers for water.

Italian cypress with foliage browning

A. Major reasons for Italian cypress dieback: Too much water. Water deeply once 3 - 4 weeks in winter and no more than about once a week in summer. Too little water. Sometimes people put these trees on just a few minutes of water from their drip irrigation system. Water should be applied so that it wets the soil down 24 inches to an area at least four feet in diameter around the tree. Depending on how quickly enough water from your drip system is applied this might take up to several hours of applied water.

Spider mites. Starts in hot weather because that’s what they like. Usually a problem on trees that were underwatered. Spider mites like dirty foliage. Wash trees with a high pressure hose nozzle after dust storms or a couple of times a year just to keep them clean. Periodic soap and water sprays are not a bad idea either.

Webbing in italian cypress may or may
not be due to the bad guys

Borers. Several people have reported borers in Italian cypress but this has never been a common occurrence in the past. I could not find it reported anywhere else either. Usually a soil-applied insecticide for borer control applied around the roots would be recommended if this were the case. Get your irrigation under control and that should solve most of the problems.

Yellowing in Palms Can Be Lots of Different Things

This is California fan palm with cold damage from
temperatures in the low 20's or high teens F

Q. We have a fan palm where the palms are turning yellow and I'm assuming dying. One or two would be acceptable but we are have 5 and 6 that are going bad.

A. Let's cover some ideas about why your palms could have yellow fronds. These are the main reasons: older fronds are dying from natural causes and should be removed; fronds were damaged during winter freezes; too much water applied too often or too little water; palms planted too deeply; palms planted in heavy soil that doesn't drain well; palms planted with pure sand around the rootball; fertilizer problems such as iron, manganese or zinc.

Not totally sure on this one but it was probably
light cold damage on this date palm during the
 winter in low 20's

Palms should be planted with the soil taken from the hole plus 50% compost and a starter fertilizer high in phosphorus added. Palms should NOT be planted with their root ball surrounded by pure sand in the planting hole which is commonly done in Las Vegas. The idea of doing that is absolutely crazy.

Palms are high water users even though they tolerate high temperatures and our desert climate. Different types of palms require different amounts of water. The larger the palm, the more water it will require. Some of the highest water users will be date palm with their huge canopy spread. The amount of water will vary but most fan palms would be happy receiving about 20 gallons every time they are irrigated.

This is Queen palm, not a good palm for the hot desert
and probably lack of soil preparation or watering too often
or both

One of the common problems is irrigating palm trees with small amounts of water, like ten or fifteen minutes of drip irrigation, daily or even twice a day. Watering like this can fill the soil with water and suffocate the roots causing them to rot, diseased or both. So if you are irrigating your palms daily, don't do that anymore!

During the heat of the summer they can be irrigated two or three times a week, using 20 gallons each time you irrigate but the soil must freely drain the water away from the tree. In the wintertime you might be dropping your irrigation to 20 gallons every 10 days or perhaps even as long as two weeks.

Sometimes the soil lacks certain types of minerals that palm trees need. Deficiencies like iron and manganese usually appears as a discoloration in the fronds at the center the canopy, the most recent growth. This can range from light green to nearly yellow. If these inner fronds are yellowing then we can usually narrow this to watering too often, poor drainage or a lack of minor elements such as iron.

Center fronds, youngest, demonstrating yellow growth
which could be due to watering issues, soil issues
or possibly disease

Next February when you make your annual application of fertilizer use a complete fertilizer such as a Miracle Gro, Rapid Gro, or Peters. You can also use fertilizer stakes. Make sure it is well balanced and try to select a fertilizer with the three numbers the same or close to the same value like a 16-16-16 or 10-10-10. Add an iron chelate that contains the EDDHA chelate in the ingredients. Let's see if that works along with irrigating with a large volume of water but doing it less often.

Cold damage on palms usually results in the older fronds turning a bronze color first and then browning later as they die. General rule of thumb is if more than half of the frond has turned brown, remove it. The new fronds at the center of the palm should be healthy and green when they emerge in mid-spring.

If your soil is heavy and holds water a long time then plant on a mound 2 to 3 feet high and 6 to 8 feet across so the water drains away from the roots.

Moorpark Apricot a Good One for Las Vegas

Apricots on short shoots called spurs

Q. We have a beautiful 5-year old Moorpark apricot tree. It has grown well and looks quite healthy. However, it seems to put out a sparse array of blossoms in spring and has a very light crop of fruit every year. The fruit is delicious. I read that the chill factor for this cultivar may be higher than our climate provides. Can I increase the chill factor by watering the branches in winter on cool days to lower the tree's temperature and thus increase the chill factor? If successful I could get a larger crop?

A. Moorpark is a wonderful apricot variety and is used extensively in the canning and fresh fruit industry in California. It is best if it receives about 600 chill hours during the winter. This means that the temperature should drop below 45F for at least 600 hours for the best fruit set.

Apricot branch in the winter
with spurs clearly visible

However, don't worry about the chill factor in this case. We have Moorpark and it has good fruit set here even after 18 years at our chill hours. The problem is more likely the fruiting spurs or lack of them. These will be the short branches along the major branches.



If these were pruned off, damaged or never developed then the crop will be light due to a lack of flowers. This year was a bad year for apricots. We had good weather and then it turned very cold in March. That freeze reduced our orchard apricot production from about two tons down to about 200 pounds.

We have had no problem with Moorpark and irregular production and it has been a wonderful producer in most years. Perhaps the location of your tree in a particular microclimate of your landscape or how it has been pruned may have more to do with it than the variety itself. But a lack of chilling is not the problem.



Zimbabwe and the Baobob Tree




Hosted at the Bradshaw's house in Harare. Geoffrey
was a fantastic guide in helping me work with local farmers

 I went to Zimabwe in August of 2011 to work with some local farmers on some irrigation schemes. They call them irrigation schemes if a group of farmers all use the same source for watering their fields. So for instance if the source of water is a river and there is a diversion from the river (can be a canal or a pump) then everyone getting water from that diversion would be on the same scheme.


Sometimes this is a very large main canal and if this main canal is split into two canals and the water can be diverted (forced to go into one or the other but not both at the same time) then each of these would be an irrigation scheme.

 

Using siphon eight siphon tubes to bring water from the
lined canal to flood their onions

So I worked with about 17 of these schemes with an average number of farmers of about 200 or so. I primarily worked with issues of "governance" surrounding these schemes (how is the water going to be managed and shared so that they all get an equal share?). But if you have never been to this part of the world then it is a treat.

The fields are irrigated on a rotational basis determined by when water is released to them by the government agency that controls water deliveries from surface sources such as rivers.

Baobob tree reaching estimated ages of 3,000 years old
or more

In southern Africa there is a tree that is quite remarkable called the Baobab or Baobob. I prefer to call it Baobob because it reminds me of me. Locals use it for as a food source by opeing the fruit (kind of dry on the inside) and sucking on the seeds. Kind of a citrusy flavor if you suck on the semi-dry pulp surrounding the seed.



It is normally found in the drier regions of the country, regions such as IV and V. The outer bark can be removed multiple times from the trees without apparent damge to them and this is then woven into mats and used in the homes or the mats are sold along the roads to people passing by, usually tourists.

Fruits of the baobob which has a pretty dry pulp on
the inside but sucking on the seeds and the surrounding
pulp of the seeds reveals kind of a pleasand citrusy taste

The outer bark is removed from baobob, woven and used for
making mats for flooring and sold along the roads

The Problem With Pruning Pine Trees So They Don't Blow Over

A fairly recent trend in pruning in Las Vegas has been pruning pine trees so they don't blow over. We have some wind gusts that periodically get pretty nasty when they reach speeds of up around 70 mph (112 kph) or more. The trend was to remove some of the canopy so that there is not so much leverage on the root systems. This leverage, or sail effect, by the wind can pop the trees over when gusts come up quickly and our trees can be pretty shallow rooted which does not help to anchor them.

This Mondale pine was pruned probably
 in an attempt o reduce with wind load (sail effect)
 on its canopyand help reduce the potential
for blowing over

You can see that removing the inner small
branches concentrates the weight of the new
growth all on the ends of the branches causing
 them to bend and in some cases to break
 

I have some concerns about thinning pine trees to allow more wind to blow through their canopies. Not that it is done but really more about HOW it is done. Take a look at this picture of a pruned pine tree just for that purpose.

Most pine trees will not regenerate new growth on older branches once this growth is removed. Once the wood is older than about three years old most pines will not cause new growth to come from this older wood. Once this young wood is totally removed, it is gone for good.

By removing these small limbs in the interior it prevents pines like Mondale from renewing the removed growth. The juvenile part of the limb is now concentrated
only in the growing tips which are all at the ends of the branches.

This might be good in theory (the tree trimmers don't have to come back as often). But this can create a problem.Think of a fishing pole. Why is the pole diameter tapered and not all the same diameter along its length?

Poles or branches which are tapered help spread the stresses of bending along its length. If a pole or branch has no taper, then the stress of bending is concentrated in a very small area of the pole or branch which will increase its chances of snapping or breaking. By removing this small wood deep on the inside it also causes these "thinned" older limbs to no longer increase in girth (caliper or diameter).They bend more and more as the weight of the new growth is added to the ends of the branches.

Pine tree with a canopy thinned a bit better so
that limbs are less likely to bend and split

A better approach would be to selectively leave some juvenile wood on the interior of these larger diameter branches so that these branches will increase in caliper and taper. So instead of removing ALL the small juvenile from branches deep in the inside, remove some but leave some as well. This still results in thinning and allows for wind to move throught the canopy easier and also results in distributing this increased load along the branches rather than concentrating the load in a small area of the branch which increases its likelihood of failure (snapping or bending).

Just a thought.

Sap Oozing from Plum Tree Trunk

Sap oozing from the trunk of plum

Q. Last week I noticed sap bubbles 6 to 8 inches off the ground on the trunk of my year old Santa Rosa plum. I removed the bubbles and reapplied the whitewash. I checked again today and they are back. I've had plums before and the boars always win. I had hoped the Santa Rosa would do better. What can I do to save this tree?

Roses in the Hot Desert Do Well But Different From Growing in New Jersey

Garden rose not doing well in our
desert soils. They can do VERY well
if you just follow some simple advice

Q. This past spring I cleared a large "L" shaped area in my yard and planted 8 various rosebushes. They have sun from about 9 a.m. to about 5 p.m. They are watered in the evening and fed regularly. They are well planted with planting medium in large holes, and then mulched. All flowered during the spring and early summer.

Now, however, they are very spindly looking. The leaves left on them are brown and the stems are turning brown. There are no bugs that I can see. I tugged on them and they are still firm in the ground. Have they died and should I replace them, or wait until spring and see what comes back? Should I cut them back, and if so, how much? I do not want to cut too much off.

Palo Verde Dont Like Butch Hair Cuts

Q. Attached are pics of a Palo Verde which has some unusual black growths on the upper sides of the limbs. I'm wondering if it has something to do with pruning, since it appears to be only in areas that have been pruned, although other pruned areas are unaffected.

Damage to upper surface of palo verde limbs from reader

Palo verde pruned too high, in my opinio, allowing for
potential sunburn on upper surface of limbs

Palo verde with sunburn damage, borer damage and
limb and trunk damage

A. My first reaction to the pictures was sunburn damage. But I would have to see if this damage was sunken like a canker.
Next I would take a sterilized knife and cut around the edge of the damage and through the damage to see if the wood below the damage was dead or not. If it was dead below the damage and the damage was sunken then it is most likely sunburn damage to the limbs.

The pics you sent had damage all on the upper side of the limbs which is consistent with sunburn damage. You wondered if it might be associated with pruning which it is. The big mistake people make on Palo Verde with the photosynthetic green bark like is pruning so much that too much light gets inside the canopy and burns these photosynthetic limbs. Even though the are designed to absorb light there is such a thing as too much light.

These trees don’t make a lot of shade and when we remove too much canopy we will get sunburn on the limbs. Once we get these limbs sunburned then we have to look for possible borer damage. They go hand in hand and several borers are general feeders and are not really particular what they lay their eggs on.

The adults focus on damaged trees for egg laying. So cut into the damage and look for football shaped exit holes about 3/8 to ½ inch long and ¼ inch wide under the damaged, sunburned bark. If this is the case, don’t prune so heavily next time and leave enough cover to prevent sunburn.

Ornamental or flowering plum leaves
with wind damage

Q. I put in a desert landscape with 2" of rock in the front yard with various bushes and 2 flowering plum trees. This probably was a mistake, as I read one of your articles which said that this type of tree is not suited for rock mulch. Anyway, my question is about watering the trees. I have a 28" diameter by 5" deep watering reservoir around each tree. There is a layer of bark mulch in the reservoir. Right now I water the trees twice a week filling the reservoir up twice at each watering.

This is purple leaf plum in a desert or rock landscape.
It will look good for about five years without much
attention. But after about five years it usually starts
with leaf scorch and may begin getting iron chlorosis

So far every summer around August some of the leaves partially dry out and turn brown. Is this caused by too much water or not enough? I water the bushes 3 times a week by drip system for 30 min per watering. They are all healthy and green. Also the bark on the trees are splitting in places and falling off. Do you think I will loose the trees at some point? Any advice will be greatly appreciated. I read all your colums in the RJ that you write. Lots of excellent advice there.

A. Flowering plums can handle the rock better because you aren’t really worried about a crop of fruit to eat. But the rock on top of the soil will aid in the depletion of organic matter and over time it will most likely turn the pinkish color that accompanies iron chlorosis in red leaved trees like the purple leaf plum. If not corrected that can lead to more of a decline in the tree opening it for dieback and insect/disease problems.

This is the purple leaf flowering plum when it has iron
chlorosis. Plants with green leaves will have their
leaves yellowing with green veins. In plants with purple
leaves the leaves will turn pink instead of yellow but
the veins will still be a darker color than the leaf blade

Bark mulch is not nearly as effective as plain old ugly mulch made from chipped landscape trees. Not many nutrients in bark, it decomposes slowly, and is all just about the same size so it doesn’t decompose as effectively as chipped wood mulch. Plus 28 inch diameter irrigation basin is not very big. As these trees get bigger they will need more water. Increase the basin to about six feet in diameter (three feet from the trunk) all the way around the tree and fill this basin which should be about three to four inches deep. Fill it twice with each irrigation.

Hard to say why the bark is splitting and falling off but I would pull the loose bark off and look for damage to the trunk such as holes for borers. The bark should be removed anyway of the trunk is dead under the bark and it is pulling away from the trunk. Often this type of situation turns into a long lingering death spiral for the tree over the next few years when it will decline more.

Fall Lawn Replacement in the Hot Desert



Upper surfaces of grass blades can help identify
which type of grass it is: L to R, Kentucky bluegrass,
perennial ryegrass and tall fescue

 Q. I need advice. We planted about 100 square feet of sod a couple of years ago. It had been doing quite well. I believe it was over fertilized 5-6 weeks back.. It is now very brown and not responding to watering. I plan on replacing it with new sod once it cools down. My question is, can I put the new sod over the old or pull out the old and re-prep the sub base? Any advice would be appreciated.

Sod removal using a sod cutter

A. You didn’t say what kind of sod it is but I am assuming it is tall fescue. Tall fescue represents about 98% of all lawn grasses in the Las Vegas area due to its tolerance, for a cool season grass, to our high summer temperatures. Before you do anything make sure it is dead. Tall fescue can appear dead but if you see any green at all at the base of the dead grass then it may just have died back.

Tall fescue is very drought resistant even though it uses a lot of water. It can dieback when water is not available and sit there for quite awhile appearing dead and then re-emerge from grass that looks dead and start growing again. This might take a couple of weeks of applying water after it turned brown. It might then be a bit sparse and you may have to seed into the grass again to get it to fill in those bare areas that didn’t make it.

Power rake, aka dethatcher aka verical mower used for
removing thatch, slicing stolons and improving
water penetration to turfgrass or lawn.

However, if it did turn brown due to a heavy fertilizer application then that is salt damage and tall fescue is not all that good in its tolerance to salt and then it is very probable you are right. You have two alternatives in replacing the sod. One is to rent a sod cutter and cut the old sod out leaving behind a ready made surface for resodding. Or you can try digging it out by hand and leveling the surface in preparation for the new sod. A lot of work. You will not be able to put new sod on top of the old sod. The old sod will leave an “interface” that will cause all sorts of problems for the new sod.

There is still yet another alternative worth considering. The dead grass is a perfect seedbed for seeding a new lawn. In about late September to mid October mow your dead lawn as short as you can and use your bag on the mower. Don’t mulch the dead grass back into the dead lawn. Next rent a power rake, sometimes called a dethatcher, and dethatch the dead lawn deep enough (you can adjust it) so that when you make a pass or two you can see soil between the dead grass blades. It is important to see bare soil throughout the dead lawn.

Patchy look to a lawn when a coarse textured grass is seeded
into a finer textured grass. An example would be seeding
K31 or Kentucky 31 tall fescue (a pasture grass) into bluegrass or
even a turf-type tall fescure with a finer texture

Purchase good quality tall fescue grass seed, 100% tall improved tall fescue and not Kentucky or K31 tall fescue, the cheap stuff. Apply a starter fertilizer such as 16-20-0 or any fertilizer high in the middle number(in this case 20) but having some of the first number (in this case 16). Seed at about 10 to 12 lbs of seed per 1000 square feet and topdress it with topdressing or steer manure with NO MORE than about 1/8 inch of topdressing. It is best to do this with a roller for applying this stuff. You can rent one from most rental places. Irrigate about three times a day for a few minutes each cycle. Irrigate long enough to wet the topdressing but not long enough to cause it to run off of slopes or puddle. Do this about 8 am, 1 pm and 6 pm. Your biggest challenge will be keeping the pigeons and other birds off of your seeding. Reduce your watering to once a day when you see grass emerging usually in 7 days or less.

A wild idea would be to not use tall fescue but a different grass seed that has high tolerance to heat in our area and a much softer feel to it. These are the heat tolerant perennial ryegrasses. They are superior to tall fescue in feel and water use but you have to get the right kind of perennial ryegrass. Some perennial ryegrasses are very heat tolerant and others are not at all and will burn up when it gets hot in the summer.

One of the best of the perennial ryegrasses is a combination of Palmer and Prelude perennial ryegrasses. It has been used on golf courses for nearly 30 years now here and does very well in the heat. You can mow it short as close as ½ inch or less (if you seed at the right rate for this kind of cut) or even up to two inches. It is soft to the touch, unlike tall fescue which has tiny hooks on the edges of the leaf blades that can cause “itchiness” some people think is an allergy which it is not. The problem is that it is only available in 50lb bags. This seed blend is available in Las Vegas from Helena Chemical Company but it will be pricey in that quantity. I could not find it on the internet in smaller quantities.

Newly Planted Apple Tree Dead

Q. I've attached a picture of what was once a beautiful, thriving Golden Delicious apple tree. Within one week it turned brown and died. It’s a young tree. I didn't plant it myself I purchased my home last July and it had just recently been planted.

Figs Grow Great in the Mojave Desert

Q. A friend of a friend has two fig trees that produce just the best figs I have ever tasted. So I am planning on taking cuttings and eventually planting them in my big back yard with full southern exposure. However we do not know what variety they are, so is there an easy way of identifying them and knowing whether they are self-pollinating, i.e. whether I need to plant two of these trees?

A. All of the figs I have tested here in our climate do well with very few problems. It is just a matter of your preference in taste. Normally, the darker colored figs such as black mission or brown Turkey have a stronger flavor. The yellow or white figs are milder in flavor. The biggest mistake when growing figs here in our climate is not watering them with enough water during each irrigation. They are oasis plants, not desert plants.

One of our "white" figs, perhaps 'Desert King'

Nearly all figs are self-fertile so there’s no need to have more than one. There are so many different varieties of figs it would be very difficult to identify which fig it might be. However, if you send me a picture of the fresh fruit so that I can see outside fruit color and color inside the fruit (cut open) I might be able to narrow it down for you.

Also, let me know if it was purchased through a local nursery since they typically carry the more common varieties. This also helps narrow it down. Follow my blog and I will give you some step by step instructions on how to propagate figs and grapes as well in the near future.

Lowering the Height of a Large Tree

Q. I have a view of the valley for a few months of the year when the leaves of many trees behind my property are gone. The partial view is still manageable the rest of the year except for a tree that is very, very full and you can see nothing beyond or through it. I know I can't ask for that tree to be topped. But what would happen if I asked for some branches to be removed in the middle of the tree so that it wouldn't be obvious to anyone? Before I go before a Board and ask such a question, I would appreciate your views on doing this and what the consequences might be down the line.

My Lawn Is Watered Enough It Has To Be Bugs!

Q. Do I have a bug problem? Spots in various areas of the lawn. I water enough.


Lawn suffering from a lack of water. Brown areas are

undefined and kind of run into each other. Pattern
of damage is related to the irrigation pattern.

A. So if you believe you water enough let’s go ahead and eliminate the possibility that you underwatering, overwatering, and getting even water coverage over the entire lawn through a properly designed and installed irrigation system.

That system should have what is called head-to-head coverage (water from one sprinkler should be throwing water all the way to the neighboring sprinkler) and a pressure regulator should be on the system so that water pressure at the sprinklers is not excessive. This helps prevent misting due to excessive water pressure.

This is the lawn disease called "summer patch". It has a
definite pattern to it. Kind of horseshoe-shaped

or the brown damage has a green patch in the center.

 Can you see the pattern?

Brown spots from watering problems usually occur in the same spots year after years and do not “move around” in the lawn. These spots are usually either next to the irrigation heads, halfway between heads or along the edges of an irregularly shaped lawn.



 So now that we have eliminated those problems since you water enough let’s move on to “bugs”. “Bugs” will usually include either insects or diseases. In tall fescue, the most commonly planted lawn grass for homeowners here in our valley, this is the time of year for disease problems. The most common lawn disease right now is summer patch and often accompanies our “summer monsoon” season.

Here is "summer patch" when you look
at a bunch of the running together.
We say the pattern has
"coalesced" resulting in tufts of green
grass growing in among the damage.

The spots start out as brown patches about 8 to 12 inches in diameter and frequently shaped like a partial circle or horseshoe. As this disease advances these brown spots blend together, if there are enough of them, into a wiggly or “snake” pattern of brown, dead grass. If you look at the green grass in amongst the dead grass, the green grass will be in circles about six to eight inches in diameter.

Make sure you are watering a few hours before sunrise, giving the lawn a chance to dry out as the sun comes up. Mow at 2 to 2 ½ inches in height. You can apply a fungicide that includes summer patch disease on the label and follow label directions.