Rolly pollies, Pillbugs, Sowbugs Potential Big Problem with Strawberries

Q. We are growing the most beautiful strawberries, the problem is that the rollie pollies are eating them before we get a chance to pick them. We have applied dicotomes earth but it has barely slowed them down. What else can we try.

A. I feel your pain. This is a tough problem. The roly pollies, sometimes we call them pillbugs or sowbugs, can be a very common pest of soft fruits and vegetables. These crustaceans (they are not insects but are more closely classified closer to lobsters) usually feed and abound in rotting or decaying plant matter which we usually call organic matter. Stuff from plants which collects on the surface of the soil where it is wet will begin to decay.

Technical information on sowbugs in the Southwest

This decaying organic matter is a usual source of food for these common pests. They can be good guys since they feed on decaying plant matter and convert it to something that can be recycled and benefit the plants. Once they get established they can get a little overzealous and start to consume other plants or plant parts which are soft and succulent.

If strawberries come in contact with the soil surface where these creatures are feeding they don't distinguish between soft decaying organic matter or soft succulent strawberries. So the control measures usually focus on keeping the strawberries from touching surface of the soil or decaying plant matter and picking when they are ripe and not letting them get soft.

This would require that the fruit be kept elevated off of the soil surface. I wish that I had a good answer for you on how to do this. I don't. Other people may recommend using diatomaceous earth but I am not convinced that this will work with your roly pollies. It is better suited for very soft bodied pests which crawl along the surface of the soil. These very sharp diatoms, at least this is the thought process, cuts or lacerates the pest and they succumb to the lacerations.

You can also use traps in the beds and remove them from the traps as they accumulate. This does not exterminate them but it does help to reduce their numbers and hopefully the damage from their numbers. These traps can be something that lies on top of the soil surface such as strips of carpet, cardboard or wood.

Removing these pests from these traps is simple. Since they like their social gatherings in darkness they tend to gather in these shady spots. Remove the shade and remove them by hand. You can also put out semi rotten tomatoes or other vegetables which will act like magnets and attract these varmints.  Then you can scoop up these rotting fruits and vegetables along with the pillbugs and dispose of them.  That won't get rid of them but it will take the numbers down. 

Sluggo Plus contains iron phosphide and spinosad and is labeled for sowbugs, pillbugs, and cutworms and is registered as an organic pest control product for gardens and available at Home Depot. The original sluggo is for controlling slugs and snails.

Harvest Garlic Different Timing in Desert Environment

Q. When do I know to harvest garlic, Walla Walla sweet onions, green onions and garlic?
 

A. Garlic should be harvested in our hot, dry climate when the tops have browned down by about 1/3. In other locations where it is not so hot they usually will harvest when the ½ of the tops have turned brown or when they fall over. We cannot wait that long in the hot desert.

A common mistake is to wait too long to harvest garlic in the desert. This is elephant garlic in the foreground, not one
of my favorites (but it is big and impresses nongardeners), but this is close to ready for harvesting. You can note the change in color of the foliage and dieback. Garlic that was in front of it was already harvested as it was an earlier garlic variety. The irrigation is drip tape with emitters spaced every four inches with the tape spaced one foot apart.

            There is a thin, tight “wrapping” around the cloves when you harvest garlic correctly. For appearance purposes and storage it is important that this wrap be continuous and tight around the cloves. If you wait too long before the final harvest, this covering starts to rot away, leaving the cloves exposed.

            Sweet onions like Walla Walla are harvested when the tops have fallen over. Do not step on the necks to ready them for harvesting unless you plan to eat them fresh and not planning them for storage.

This is Contessa sweet onion. The top of the plant in the center has fallen over signalling the bulb is ready to harvest.
The others are close but not ready yet. When the bulb is ready for harvest the neck will collapse near the bulb and
the weight from the top will cause it to fall. This closes off the bulb and will not allow diseases to enter the interior of
the bulb and helps for long term storage. The other thing to do for storage is cure the harvested bulbs. Leave the collapsed
tops on the plants and put them off the ground and in the shade to cure for a few days.
After the tops dry down, cut them off leaving an inch of the dried top remaining.

            The drying down of the tops and tops falling over is a natural “sealing” process of the bulb. Stepping on the tops can allow disease organisms to enter the bulb because the neck has not dried down properly and may prevent any storage of the bulb.

            Scallions are really nothing more than green or immature onions that have not yet begun to bulb, just barely started bulbing or cannot bulb. In the case of the Welsh onion, which is traditionally grown as a scallion, it cannot bulb up. White Lisbon onion is also grown as a scallion but this onion will bulb up if left in the ground too long. Harvest it before it starts to bulb.

 

Should I Add Vinegar or Citric Acid to My Water?

Q. Have you ever heard of adding vinegar or citric acid when fertilizing indoor plants in our area? We collect the rain water and use it for our indoor plants.



Diagrammatic representation of pH scale
as found at
https://en.wikipedia.org/wiki/PH
Numbers are logarithmic so each unit
change represents a factor of 10 (e.g.
6 to 7 = 10; 6 to 8 = 100; 6 to 9 = 1000)
similar to the same scale used for
measuring earthquake intensity. 

A. Quite a few people do this to lower our water’s alkalinity but the effect is short-lived. Our tap water carries a lot of calcium and magnesium salts. The acids are neutralized by these and other salts.

You could determine how much acid to add fairly simply by using some pH litmus paper, like they use for swimming pools. You would add small amounts of acid until you see a shift in the pH of your water into the acid range.

The perfect pH is 6.8 which is the pH of the plant sap of many plants. Let this water/acid mixture sit for 30 minutes or so and check it again. Keep adding small amounts until you see the pH stay steady in that 6.8 pH range then you can use it for watering.

As long as you stay with the same water source, you would add the same amount of acid each time to arrive at basically the same pH. If you change water sources, then you would have to do it all over again.

However, as soon as you pour this mixture on our soils it will shoot back up again to the alkaline range because of the massive amounts of alkaline types of minerals that reside in our soils. In short, I wouldn’t waste my time doing this unless it helps you sleep better at night.

Just adding a big scoop of good compost to your water instead of vinegar will probably do more good. Let the compost steep for a few hours through a porous sock like old pantyhose. Use it immediately for watering. Put the spent compost around some outdoor plants or in your garden. Good compost is likely to still have gnats so don’t apply the spent compost to the soils of indoor plants.

Eliminating Lawn Can Lead to Problems for Established Trees

Q. I have a beautiful Loquat tree where the leaves have suddenly started to turn yellow and fell off.   Most of the fruit has also fallen off. The tree was located in the middle of grass. I had the landscape converted to desert rock in September. At the same time watering schedule was changed. I suspect it is being under watered. But before I increase it I want to ask if the cold winter we had here could have caused this yellowing.

A. Thanks for the pictures. It is probably not the cold. In a lawn situation the roots go everywhere and anywhere and usually spread to about 1½ to 2 times its height away from the trunk.

Loquat with rock mulch applied after growing in a lawn for a few years. In many cases the drip emitters do not
apply the water in the same places as lawn irrigation and the plant roots of established trees and shrubs die back.
This results in leaf drop and eventual die back of the limbs of established trees and shrubs.

            In drip irrigation we usually place the emitters a foot or so from the trunk. This bypasses about 80% of the root system it created when growing under a lawn.

            So, yes, it probably is drought but perhaps not because you are not delivering enough water. It is more likely that most of the tree roots are not receiving water. You can place emitters over a greater area under the canopy of the tree. But I would also reduce the size of the root system.

            Try root pruning the tree to reduce the size of the root system so it is closer to the emitters. Keep tree roots contained in the area directly under the canopy. Wet the soil thoroughly under the canopy and vertically slice the roots in a circle all around the tree at the edge of the canopy. This can be done with a sharpened spade.

Leaf drop of established loquat due to replacement of lawn with rock mulch and drip irrigation.

            At the same time, thin the canopy by removing wood. This reduces the tree’s demand for water. A tree that size will probably require 20 to 30 gallons each time you water. With the lawn now gone, the tree will actually use more water since the cooling capacity of the lawn has been removed.

How to Keep Harvested Garlic a Long Time

Q. I know garlic will keep 4 to 6 months in cooler climates. Since I don’t have a root cellar, what are my options for storing garlic?

Tom at the Orchard tying garlic in onion netting for storage and sale. You can use pantyhose
and cut the bulbs loose from the netting when one is needed.

A. After harvesting garlic from the field or garden, we will tie the garlic together in bunches and let them hang outside to dry in the shade for a week or two. This helps “cure” the garlic bulb and readies it for storage. Some people want fresh garlic and in this case it is not “cured” but should be consumed soon.

            Ideal storage environment is cool and dry, away from other food items that might absorb the flavor of garlic. Garlic under home conditions will store for about 2 to 3 months in a kitchen environment.

Garlic hanging under shade cloth, tied in bunches, for curing for a couple of weeks.

            An option is to dry the garlic and it will store indefinitely. If you still have garlic left after two to three months of storage, you can peel it, slice it thin by hand or in a food processor, dry it outside in the shade and low humidity of our Las Vegas environment. Always dry food in the shade, not in direct sunlight here. Keep drying temperatures below 140F if using a commercial drier or oven.

You Missed the Planting Dates for Onions if its April

Q. I need to get the bulbs of onions (yellow and red) and garlic planted now that it is April.  I was thinking of planting them in the semi shade of my Texas ranger shrub. The ranger grows along a wall that faces West so this area doesn’t get full sun until 1-ish.

A. You have missed the planting season for onion transplants. This would have been in mid-March in our climate.



Onion transplant on either side of drip tape

            Onions can be started from seed but onion seed is planted normally in late September to mid-October. Onion seed will germinate in the fall and overwinter with periodic waterings. I normally plant onion seed close together by broadcasting the seed in a small area and putting about ¼ inch of topdressing and mulch over the top.



            In mid-March I “lift” the young onion plants (transplants) with a spading fork for planting in rows that are about 12 inches apart and four inches between transplants. Onions are planted in full sun. They will not do well when planted in competition with other landscape plants like your Texas ranger.

            Garlic “seed” are not seed at all but the cloves inside the garlic bulb. These “seed” are separated from the bulb and left in the shade to heal over for a few days. They are then planted in a permanent location in the fall, the same time as onion seed. Garlic is harvested from May through June depending on the variety.

            Get ready to start onion and garlic in the fall and plant transplants of onions in mid Spring.

I would not mix onions with your Texas ranger. The competition from the Texas ranger will not be good for the onion. They will compete with each other for space, nutrients and water. This will result in not developing good size for the onion (unless you don't care about size). If you do want to add onions to your landscape I would do them in planting blocks of their own away from shrubs or trees. Just make sure you give them appropriate soil preparation and enough emitters to get good water distribution for their growth.

Fertilize Garden Plants When They are Growing



Blood meal is one form of organic nitrogen
that can be used to side dress

            Earlier in the season, around mid-March, I was encouraging you to plant your own onion transplants and grow your own onions. They are so much better tasting and I gave the readers here and on my blog some varieties to choose from. Many are available from seed and started from seed in about mid-October, the same time as you would plant garlic.

            Most people forget a very important concept in their home gardens – regular fertilizing. As plants get bigger or start producing they are taking all of these “goodies” from the soil to get bigger or start producing. I will get back to onions in a minute.

            What would happen to you if you were always giving and receiving nothing in return? Plants can’t continue to “give” without getting something in return if you expect them to be healthy and productive. So all plants as they get bigger and you harvest require fertilizer.

 

Plant health depends on regular fertilizer applications if you are always "taking".

 

"As expectations for plants increase....more inputs (water, fertilizer, time, energy)are needed."

            Fertilize your garden plants monthly when they are producing. Think about what they are taking from the soil. Was the soil enriched at the time of planting so they have plenty to “pick from” or is the soil’s nutrient reserve running low?



Ammonium sulfate granular fertilizer also known as
21-0-0 since it is all nitrogen (21%) and no phosphorus or
potassium

            The first nutrient to disappear from the soil, for a number of reasons, is nitrogen. It is very important to supplement your vegetables with some extra nitrogen monthly.

            If the plants are up and growing it is not wise to just broadcast the fertilizer (throw it out over the garden willy-nilly) or the fertilizer “salts” may burn foliage. Deposit the dry fertilizer next to each plant or dribble it along the row. This is called “side-dressing” with nitrogen.

            Why did I mention onions earlier? Because they need to be side-dressed as well and are frequently forgotten. One more side-dressing on onion and garlic and then stop as you will be harvesting in two months.



Ammonium sulfate is a crystalline source of nitrogen that
dissolves easily in water and can be applied as a granualr
or liquid by dissolving it in water. Dissolve about one tbs
in three gallons of water or apply it dry by sprinkling on
the soil lightly and watering it in

            Use your favorite source of nitrogen. If you are an organic gardener, select an organic form that you like. If you are not that fussy, then use a traditional ag-type nitrogen fertilizer like ammonium sulfate. When you side-dress, it is normally just nitrogen as it moves into the soil freely with an irrigation.

            If these are annual plants, all the other nutrient “goodies” we normally put in the soil at the time of planting.

            What makes big onions? The variety you select, improved garden soil, spacing them 4 to 6 inches apart, regular and frequent watering, weed control and side-dressing with nitrogen as they are growing and expanding. Pull or lift them when the tops fall over naturally. If you are pulling them, make sure the soil is wet when you are pulling or you will pull the tops off.

            Remember, my blog, Xtremehorticulture of the Desert, has a lot of pictures that supplement my discussions here.

Watering With Distilled or RO Water a Problem?

Q. In a past posting on your blog you mentioned that using 100% distilled water for container plant irrigation might mess with the potting soil.  What did you mean by that?

A. Distilled water has no minerals in it. This can pose problems for soils and cause the soils to “deflocculate” which means the soils can start to seal and begin to slow the water movement through it by taking minerals from the soil particles.

            So it is best to add just a small amount of fertilizer…very little… so that you replace the minerals that are no longer there. Think of it similar to drinking distilled water as opposed to water that has some “good” minerals in it and the effect on our bodies.

            So good salts to use for replacing the salts taken out would be fertilizer salts from a good quality fertilizer or a light compost tea. How much to add? How much salt remains after water evaporates from irrigation water? Very little. A pinch or two of a fertilizer salt in a gallon is enough.

Fertilizer for Cactus Is Limited by the Quality of the Soil

Q. I was wondering whether you could help and point me in the right direction. I had been using a great liquid fertilizer which I was able to obtain from the 99 cents store in Henderson. They have discontinued the product and I can't seem to find it anywhere.  I have succulent plants and cacti on my patio and the liquid fertilizer really seemed to help. Could you suggest where I might obtain the liquid fertilizer or suggest some other product for my plants?
 

A. I know you probably got a pretty good deal with that fertilizer and that may not happen again for a while but there are some good liquid fertilizers out there. Sounds like you are into the bargain bins when you buy things so you may not like my suggestions.

Good fertilizers are nearly never inexpensive. One of the best ones you could use would be to make your own compost tea using high quality compost. I can’t compare all the products out there available in Las Vegas but one that I know about is called Happy Frog compost. Be careful when using it because it has had fungus gnats in it still working the compost so don’t use it inside the house. It is fine for making tea or using outside (our desert heat will kill the gnats).



Happy Frog products are good quality organic products to use. There are others but this is one.

You take about two handfuls of this compost and put it in about a gallon of warm water and let it soak overnight. No longer than this because you want the water to have air in it or the process will go anaerobic and kill all the microorganisms. Or bubble air through it to keep the microorganisms alive.

The soaking will leach out a lot of the nutrients and microorganisms (goodies). Happy Frog still has a lot of microorganisms in it. Many do not. Use this gallon of water to water your flowering cacti.

If you want a mineral fertilizer then any fertilizer made for tomatoes or roses will do well. Just use very small quantities. Products to look at include Peters, Miracid, Miracle Gro, Jobes, and others.

Peters makes excellent fertilizers but they are expensive.
In many cases, you get what you pay for in
fertilizers

Most importantly for cacti, make sure you amend the soil when you plant them with organic material such as compost or some manure based amendment. Cacti do much better in an amended soil than pure sand or our unamended native soils. If the soil was not amended, lift them during the warm months and replant using soil that drains freely and incorporating compost into it.

Milky Spore Product Probably Not Best Choice for Southern Nevada

Q. In my attempt to plant seedlings this year in my 4x8 raised bed, I noticed the day after I planted some pepper plants they were decimated by some kind of insect. When I was amending the soil a few weeks before, I noticed some small worm-like critters in the soil. I sprayed a bit of Bt on the soil but it evidently didn't do anything to help the situation. I was told to use a powder called "milky spore disease” to kill any grubs or grub-like insects. Have you ever heard of this product? They said it works and I only have to apply it one time. Sounds too good to be true. This store said they used to carry the product but not any more for reasons unknown. I went to the Home Depot and Lowe's, but neither store had the product.

Can you advise me on this product and where I might find it or some other solution?  I removed the damaged plant and I'm trying to revive it.

A. The milky spore product only works on some types of insects such as Japanese beetle which we do not have in southern Nevada, and a few closely related insects. “Milky spore” is a bacterium and works rather slowly, if it will work at all, on pests in southern Nevada.



Cutworm larva

Bt works on those insect larvae that mature or pupate into either moths or butterflies. So if the larva turns into a beetle, for instance, it will not work. So without knowing which insect larva you have it is hard to know what will work unless you use a conventional pesticide approved for use on vegetables and has insect grubs or larvae on the label.

This time of year Bt is a good product to use in home gardens because of the presence of cutworms. I am sending you a picture of what the cutworm larva looks like and its adult form (posted also on my blog), a moth. Bt can be sprayed on the soil and left undisturbed (no hoeing or irrigating) for a few days.

Dipel in this form is a dry flowable product. Dry flowable pesticides
are the same as what we call "water dispersable granules". These can
be mixed with water and they disperse in water easily and quickly BUT
the spray mix MUST be constantly mixed or shook while applying or
the pesticide with settle out and you will not be applying it anymore
but will collect at the bottom of the sprayer

This is the time of year that this moth is flying and laying eggs. Their larvae “hatch” from the eggs and are out looking for food right now. Usual cutworm damage is at the soil surface, not on the leaves. Other products to try to protect your plants are those that leave a poisonous residue for insects on the leaves. You can also use insect netting covering the rows in a low tunnel.

 

Science in Action: Controlling Borers in Landscape Trees

Options available for controlling borers have actually increased over the past few years. While the traditional approach of spraying an entire plant with a chemical such as Lindane, a chlorinated hydrocarbon, has become less available to pest control operators other types of IPM (Integrated Pest Management) control strategies have blossomed on the commercial market. The problem for most applicators is that the "security blanket" of a traditional pesticide approach is disappearing and the research to support the newer products is not available to give applicators confidence that they will work.

The IPM model for borer control includes strategies such as cultural, chemical and biological methods. The most effective long-term control strategies are usually cultural in nature and should be our first consideration. Often times they are not used by commercial operators for a variety of reasons but usually get back to either economic reasons or lack of education on how to use them effectively.

 

Flat headed borer in small limb of peach tree. Sanitation would be removal of the small limb or cutting out
borers from larger limbs with a knife

When evaluating which method to use, we have to balance the efficacy of the control measure, it's economic benefit to the customer and the operator and impact of the control measure on the environment. Lets take a look at each component in the IPM scheme.

Cultural control options in traditional agricultural IPM include sanitation, crop rotation, tillage, host plant resistance and tolerance, mechanical or physical destruction of the pest and quarantine. Do any of these apply to controlling borers in landscapes?

Sanitation refers to the removal of infested plants or plant parts which helps reduce the level of plant pest in the urban landscape. This may mean removal of entire trees heavily infested or removal of limbs to reduce the infestation level. This can be done on an individual yard basis or community wide if there is a community "epidemic" of a particular pest.

Borer infested limb removed to save the tree from removal. A form of sanitation.

We have seen communities, or entire sections of a community, devastated by certain types of borers. Clear winged borers, like the ash or lilac borer, can be serious pests in this regard since these types of borers are known to attack healthy trees and the number of these insects in a community may dictate the degree of infestation and damage. Community-wide borer control efforts need the strategy of a community forester or city arborist to make these efforts work.

Crop rotation is the substitution of a crop (plant) with low pest susceptibility (host resistance) for a plant with high pest susceptibility. As an example, if we lose a tree to borers do we put the same type of tree back in that community or do we look for a reasonable alternative? As we begin planning a community or expanding a community are we checking to see what borers are problematic to the community or are we selecting plants only because they have aesthetic appeal? An example of this is the planting of weeping willows in climates like Las Vegas where they stress and become highly susceptible to attack by borers. These trees then become a source of infestation for other susceptible trees in the community. A proactive approach toward sound horticultural growth, balanced by future maintenance, requires public education and community coordination.

Weeping willow planted in Las Vegas with borer damage from clear-winged moth. For this reason
we never see weeping willows over about ten years old.

Quarantine is a legal restriction or exclusion of infested plants being brought into a community. On a state-wide basis, inspection stations are established that control the entry of infested plant material or documentation is required by the buyer that plant materials have been inspected, and found clean of, certain pest problems. Sometimes plant materials are simply not allowed into certain communities due to the highly virulent or infectious nature of certain pests. This has happened with elm varieties, and some of its relatives, known to be susceptible to Dutch elm disease.

Some arborists combine physical or mechanical control measures with their borer protection programs. Physical control can be as simple as noting borer activity in some young trees and carefully using a small knife to remove or kill the borer. This will work with borers such as some of the flatheaded types that that can be easily tracked and that feed near the surface of the trunk. A great deal of care has to be exercised so that the tree is not further damaged with the knife but with some experience it can be learned. Mechanical control includes barriers such as wraps that may help prevent sunscald and the physical entry of borers inside the tree. Some care has to be exercised that certain wraps don’t actually contribute to the problem by providing egg-laying sites for borers.

We are all most comfortable with cover spray applications of chemicals for borer control. This strategy was either to spray the plant periodically through the entire growing season or time the spray with some sort of insect trapping device. Cover sprays applied a poisonous, pesticide barrier to susceptible plants. The traditional approach was to apply a pesticide to the trunk and major limbs of trees either infested with borers or "threatened" with borer activity. This cover spray was a prophylactic treatment aimed at preventing the entry of the borer inside the tree. Once the borer entered the tree, cover sprays were ineffective.

Emerald ash borer damage to green ash which we do not have
 in southern Nevada

Our business practices, equipment and past education focused on chemicals for borer control. The problem with traditional cover spray applications of chemicals is that the chemicals traditionally used for this purpose pose a threat to the environment and human health, both by the nature of the chemical and how it was applied. This technique is still probably the most widely used one but is becoming more restricted with time. We have already seen Lindane become more restricted in its use and availability. Admittedly, using chemicals such as Lindane, Dursban, Thiodan and Sevin as cover sprays on large trees has its community environment and health drawbacks. The effectiveness of cover sprays always depended on a narrow window of time when the spray would be effective.

Applications of chemicals such as Metasystox R as a soil injection for borer control pose similar environmental problems. Applications of pesticides into the rootzones of plants pose an immediate threat to shallow groundwater supplies, wells and public health concerns.

 Application methods of pesticides such as trunk injection certainly minimize some of the environmental and community health concerns. Active injection systems exist, like Mauget, which rely on a pressurized system to inject pesticides such as Bidrin and Merit, into the tree's vascular system. Once inside the tree these chemicals become mixed with the vascular fluids and thus become systemically distributed. There are passive injection systems, such as trunk implants, that have no pressurized system but rely on the vascular fluids to carry the pesticide throughout the tree. This mixture of vascular fluid and pesticide poisons the immature borer feeding on the vascular tissue.
 

 How to Use Mauget trunk injection

 

In my opinion, never use systemic insecticides or inject insecticides systemically into fruit trees or other edible crops.

 

Entomologists have been concerned that trunk injections, made late in the protected borer's life cycle, would not be effective. They reason that borer feeding activity disrupts the flow of vascular fluids and prevent the pesticide from coming in contact with the borer. In the case of borers in an advanced stage of its life cycle, this may be the case. However in the very early stages of an infestation, injection may provide some measure of control.

The injection of pesticides into trees poses other problems such as the damage created when holes are drilled into the trunk. Research many years ago in the United States and Canada has both come to the same conclusions. If holes have to be drilled into trees then the holes should be as small as possible. The other piece of research conducted with injection equipment is that on larger trees, injection should be made as low on the trunk as possible. Injection holes drilled in the root flares provides better mixing and a larger trunk circumference to absorb the damage created from drilling the holes.

Xtremehorticulture of the Desert Exceeds 20,000 Hits per Month

I am excited that my blog now consistently exceeds 20,000 hits or visitors each month. My blog is my way of paying back to southern Nevada residents for all their support over the last 30 years in my tenure with the University of Nevada. I have learned alot about horticulture over the years teaching and conducting research in southern Nevada. It is a shame to retire and have that information retire with me.

I hope you can use the information I am providing and, in the process, make you better gardeners and horticulturists.

I have returned from my assignment in Northern Afghanistan and I am excited to share some of what I learned there. I was concerned sharing much at that time due to security issues. Any pictures of individuals who worked with me there must have their faces blurred for obvious security reasons. Please bear with me when I share these experiences. Northern Afghanistan's climate is very similar to southern Nevada and their crops and planting schedules were nearly identical to ours. So stay tuned. More to come.

Saguaro Leaning and How to Correct It

Q. I have a saguaro cactus with three big arms growing from it leaning toward the west. On the east is my house and shading the cactus from the morning sun. I also have been watering on the house side of the saguaro, the up slope side, and letting the water run downhill into the roots.  I water about 3 or 4 times a year and water very slowly.

Do you have any suggestions about either stopping the continued leaning or how to straighten the cactus to upright?  Those two large saguaros have been in my yard for 17 years.

Saguaro leaning due to shade from the house most likely

A. These Sonoran desert monsters are top heavy. The root system of the saguaro is fairly shallow but expansive. This extensive but shallow root system can give this top-heavy cactus quite a bit of support under native desert conditions. But they have been known to blow over in high winds.

These cacti, like most, are opportunists and take shallow water from the soil before it evaporates or taken by neighboring plants. Most of the roots away from the trunk can be found at depths less than 12 inches. Watering deeply around these plants is probably a waste of water.

We put these plants in artificial desert landscapes and put them on drip emitters or run water close to the trunk. This can lead to a very small but dense root system close to the trunk. The roots don’t have to grow far from the trunk for water and so doesn’t help to stabilize the plant as the top gets bigger.

Saguaro normally does not need to be staked when transplanted but here is one method that protects the trunk

Your cactus could be leaning either because of the shade from the house or it might be leaning due to poor root support or both. If it is leaning and there is danger it will fall over then you will have to support it.

In the meantime, we create a more expansive root system by placing enough other desert plants close to this plant so that the irrigations from these other plants can help the saguaro extend its root system further from the trunk.

We could sprinkle irrigate the area around the saguaro, simulating desert rainfall. But sprinkler irrigation can lead to weed invasion in the landscape and weed control problems.

From the pictures you sent, obviously your watering regime has given your saguaro some good growth but it sounds like the water is concentrated close to the trunk. I will post the pictures of your saguaro on my blog for others to see.

Another possibility that could contribute to the leaning is how it was planted. If a hole was dug just large enough for the transplanted roots, and the soil was not conditioned properly, then this will encourage the plant to grow roots close to the trunk as well.

All cacti grow better in amended soils than in straight desert soils or sand. Always amend soils for cacti at planting time.

What can you do now? If the plant is leaning due to the house there is not much you can do. To give it better support put irrigation water at greater distances from the plant and use shallower irrigations.

Like I said, giving saguaro deep watering is not going to help but getting its roots to grow wider might. If the soil is not loosened, it is best to loosen the soil surrounding the plant where you are watering to encourage growth at distances that will support top growth.

Keep the Birds Out of Ornamental Grape Vines by Removing Flower Clusters

Q. I bought a house last December that has two large grape vines growing over a pergola that covers a hot tub. Last summer when the vines were producing grapes, the birds were unbearable. I know I could cover the whole thing to keep the birds out but it would ruin the aesthetic and make access to the hot tub difficult. Is there something I can to keep the beauty of the vine without it producing any grapes?

This is a grape spur that has been pruned for producing good quality grapes. The top stem is reddish brown. At
the base of the reddish growth is greyish-brown. The reddish brown growth will produce grapes because it grew
last year. The greyish brown growth is older and will ot produce grapes. If all the reddish brown growth is removed
from the vine, the vine will not produce any fruit

A. Yes you can. It is a fairly easy solution. In the winter months prune out all the new growth. You can see it because it is a different color than the greyer oldish growth. Grapes only flower on the wood that grew last year.

            Or it should be flowering now or very soon (late March). As you see these flower clusters on the vine, pull them off.

These are unopened flowers of grape. They come around late March to early April in southern Nevada. The come
from the reddish wood produced last year. Either remove all the reddish wood during the winter or early spring or
wait until these flowers come out and remove these clusters. They snap off easily so you could probably knock them
off with a broom if you don't want fruit

When and How to Prune and Fertilize a Cassia

Q. My cassia is full of beautiful yellow blooms. First year this two year old plant has done this. When do I trim it back and how far?  Type of fertilizer will it need?  

The base of cassia has several strong stems coming from the base. Choose one or two of these strong stems and remove
then at the base. Let it regrow from the base to rejuvinate it and let the leaves fill in from top to bottom from the
strong young basal growth.

A. Shrubs or other plants should be pruned soon after they flower. In spring flowering plants the flowers are produced during the late summer and fall months. Some finish maturing in the spring before they flower.

But regardless, if these spring flowering shrubs are winter pruned with a hedge shears it will remove the spring flowers. If shrubs are pruned properly and not pruned with a hedge shears they then can be winter pruned. Hedge shears should be reserved for nonflowering hedges.

Reach down inside the canopy, or from the outside, cut with a sharp and cleaned pruning shears about one inch above the
surface of the soil and make your cut. Pick stems that are the largest or too close together.

Pruning should be done with a few well-placed cuts deep inside the canopy to remove sections of the plant which are crowded, too tall or too wide. Cuts are made where two stems join together, removing the offensive stem.

This results in a general thinning of the shrub removing larger diameter wood. By removing larger diameter wood, this “renews” the shrub and helps keep it young. I hope this helps.

Center of Cassia Bush Died. What to Do?

Q. I have a cassia at the corner of my house to block the street view of my air conditioning unit.  The whole center section visible from the street has died.  I'm beginning to cut out the dead limbs. I check the cuts but am not seeing any green at the bark.  Is there a chance that partially cut back limbs might still produce new growth?  Or should I cut back to the main trunk?  With no center section it looks ugly. Can I hope the living branches will fill in eventually?  Dig it out and replant with a new one?



One of the cassias and what it should look like with proper care as it is getting at the Las Springs Preserve

A. Yes it is possible you had some winter kill but doesn’t sound like winter kill. Winter kill is most common on new growth, such as the tips of branches, if temperatures are just below their tolerance. If temperatures a considerably below their tolerance, then you will see death also in the older, larger diameter wood.



This is what a cassia will look like armed with hedge shears, improper watering and lack of
fertilizer 5 years after planting.

It is odd if it is just damaging the interior wood and leaving other parts of the plant alone. Another possibility is root rot if it is watered too often or the area is flooded. This should be fairly easy to determine by pulling the top of the plant toward you and looking at the base of the plant.

In cases of root rot, trees and shrubs the plant will not be securely anchored in the soil. When you pull on it the base will move around and not be firmly anchored in the soil.

In healthy plants that are not winter damaged you should be able to scrape the soft outer bark with your fingernail and see green beneath it. This is not easy to see in all plants. But at least the inner bark should be cream colored or white.

So I would not cut anything back at this time. If there is winter damage then the killing temperatures already “pruned” it back. If the plant or plant parts are alive they will show you where to cut after new growth emerges. When it emerges, cut a few inches below the dead part of the limb and into the strong growth, just above a bud or at a crotch (where two stems come together).

If you don’t see any new growth by mid-April, then it is dead. Whether to remove it or not is really a subjective call and not one I can direct. It is your call. With an established root system it should grow back very rapidly and will fill in the spots where there is strong sunlight.

Pink Leaves on Purple Plum Probably Iron Problem

Iron chlorosis on purple leaf plum

Q. I have two red leaf plum trees both about two years old. They started the year beautifully. One continues to look normal but the other one has all of a sudden taken a turn that bothers me. The leaves are getting pale, pink instead of red and see through-ish. It is a nice full tree yet young. Is it as simple as not enough water or something else? It had a great year last year.


A. It is most likely iron chlorosis. If you want to see if that is the problem try making a few liquid applications of an iron chelate to some leaves using a spray bottle to see if this turns them dark purple (I am assuming you have a purple leaf plum).

            It may take four or five applications with a spray bottle to the same few leaves a couple of days apart since liquid applications to the leaves are not typically as effective as applying it to the soil. Otherwise buy some iron chelate containing the EDDHA chelate and apply it to the soil in a bucket of water and wash it in around the roots.

            You should see it turn dark purple in growth that comes out AFTER you make the application to the soil. This discoloration is also possible if the tree roots are being kept too wet by watering too often or you have poor drainage.

Asparagus Should Be Cut Below the Soil Surface

Q. I have a raised bed (5 x 10 feet) dedicated to asparagus. The yield has been magnificent. However, the plot has gotten so overgrown with old asparagus stumps that I have had to totally remove and replace all the soil because cultivation was impossible. My question is how long can an asparagus garden last without being so impacted that it must be replaced; or, is there a way to deal with spent stumps annually to prevent this problem.




Purple passion asparagus with some rabbit damage. Rabbits love the
higher sugar content of Purple Passion

A. Asparagus rhizomes are normally planted about 12 inches below the soil surface. If started from seed, the seed is planted in a trench and backfilled as the plants grow so that the developing rhizomes are still at about 12 inches deep. 

Asparagus crown for vegetative propagation. Selecting crowns that
are male will guarantee a male crop. Spears emerge from the top
where the fleshy roots come together

When this is done the spears can be harvested by cutting below the soil surface with a knife so that these "stumps" don't stay on the surface. If you harvest the spears by "snapping" them or breaking them above the soil surface then you will get these woody stumps remaining above the soil surface and they interfere with future harvesting.

So, in short, if you can harvest by slicing with your knife an inch or so below the surface I think this will stop your "stump" problem. The woody part is cut off after harvesting during food preparation. The woody part should compost fairly easily.

Snapping off spears will cause the spear to break just above the woody portion. Nice
for the kitchen but leaves a "stubble" behind in the asparagus bed

Recent research has pointed out that asparagus spears can be harvested anytime the spears are pencil diameter or larger five inches above the soil level. Smaller spears should be left to grow into fernlike growth to replenish the roots for upcoming seasons. The plant is still expanding its root storage system and excessive removal of spears weakens the plants. However, there is a market that has emerged utilizing these very thin spears.

In commercial operations all spears are harvested cleaning the entire bed and spears are allowed to grow to ferns only after the harvest period. An asparagus plant will yield an average of 8 to 12 spears per year before the roots need to be replenished by letting the spears develop into ferns.

Harvest spears by cutting or snapping. To cut a spear, run a knife into the soil at the base of the spear and carefully sever it. Because the spear cuts below the point where fiber develops, it becomes necessary to remove the fibrous base from the tender stalk. Most homeowners and some small scale growers prefer to snap the spears. This eliminates any woody growth on the harvested spears. This does however leave a "stubble" on the surface that can make harvesting more difficult.


To snap a spear, grasp it near the base and bend it toward the ground. The spear breaks at the lowest point where it is free of fiber. Stalk diameter is not a good indicator of proper maturity and associated tenderness. Hydrocooling, or plunging freshly harvested spears into cool, clean water is strongly recommended.

Commercially, asparagus is graded by class (US Number One and US Number Two which are based on straightness and head compactness) and by diameter 5 inches from the tip (see table) according to USDA standards for canning asparagus.

Stems of Beans Devoured at the Base



Beans planted in cool soils can get collar rot or get devoured by cutworms

Q. I found a couple of beans in my garden that have been devoured at the base. Could it be some sort of soil born larva or possibly a virus?  Any ideas would be helpful. I did find one small white worm about a half of a centimeter long near the root about an inch away. 

 

A. It could be a couple of things. First, with cool weather and cool soils it might be collar rot disease that rots the stem at soil level. This will happen if you plant beans too early in cold soils. Some varieties of beans are more susceptible to this than others.

Most likely cutworm damage

            The first indicator is that some plants appear stunted and grow poorly.  I usually end up removing these plants and hope the weather warms up. 

            The other problem can be cutworms.  You should be spraying or dusting the soil surface around these plants with either Dipel or Thuricide, an organic pesticide.  This is the time of year you should be doing that anyway for a variety of pests in the vegetable garden.