Bee Magnets for Desert Environments

Q. Any suggestions as to plants most attractive to bees which flower for the longest periods? 

A. Annual flowers will give you the longest flowering period during the summer. There are some perennial herbs like rosemary, mint, oregano, burnet, coriander and borage that, once flowering and continue to flower, make great bee attractors. It’s an annual but bees love basil.

            Don’t forget ornamental grasses. Bees collect a lot of pollen from grasses that are left to flower. Warm season ornamental grasses might include Japanese Silver Grass, Fountain Grass, Switch Grass and Prairie Cord Grass.

            Flowering annuals to use include cosmos, calendula, asters, cornflower, small sunflowers, alyssum and clovers to get you started. Plants in the rose and legume families are usually great bee magnets.

            Always plant annuals in the spring, two to four weeks before temperatures begin warming up. If they are perennials, then you can plant in the fall or spring. If you want to do a little planting yourself from seed then buy some Ligularia, Valeriana and Phacelia.

Please Help Me Save My Plumbago!

Q. Please tell me how I can save my potted plumbago from our Las Vegas winters.

A. So you have a plumbago. People like them because of their blue flowers which fade to a bluish white in our intense direct sunlight. It likes our summer heat if it gets a little relief from the afternoon sun so Eastern exposure is best or filtered sunlight.

            There are a couple of different kinds of plumbago so I'm guessing yours is sometimes called Cape plumbago. It hails from South Africa hence its name. so it likes the heat, can handle an occasional drought and moderately poor soils.

Do you want to see a plumbago? 

            It does well in our desert heat but does not like our soils, unless they are amended with compost, or our winter cold. This plant does well in a Mediterranean type climate which might get light frost. We normally see it growing in South Florida and along the coast in Texas. It used to be grown in the warmer parts of Arizona and along the Colorado River until desert landscaping pushed it out of our landscapes.

            You are worried about losing it to our winter freezing temperatures. If the plant has been established for at least one growing season it can freeze to the ground and come back again much like Bougainvillea.

            You have it growing in a pot so move it into the garage if the temperatures appear to go below freezing during the night. Other than that, treat it like any other winter tender, potted plant. If there is a light freeze, throw a crop cover over the top of it and make sure the cover is all the way to the ground. During a heavy freeze this won't be enough protection.

            Make sure you repot this plant every 3 to 4 years. Fertilize it every other month with a rose or azalea type fertilizer and iron chelate applied to the soil and watered in. Make sure the soil drains easily and keep it slightly on the dry side between waterings. 

Eliminating Bermudagrass from Lawns

Q. Can you help me and suggest how to eliminate Bermudagrass in my grass lawn please? It spreads like crazy. I’ve tried Round-up weed killer but no success. The roots are so deep.

Bermudagrass has stolons that creep or run along the top of the ground. They also have underground stolons that grow in a similar way.

A. Roundup will kill Bermudagrass but apply it at the highest rate allowed on the label. Roundup is systemic which means it kills the plant further from where it is applied, perhaps as much as 12 inches.

            You’re right. Plants with an extensive root system will only be “burned back”. They are burned back about 12 inches from the point of application. It needs to be applied several times as new growth pops up in new locations.

            Bermudagrass doesn’t like shade. It won’t grow in the shade of trees for instance. It is prevented from growing in a lawn because of the shade made by the lawn grass on the soil surface. As long as shade remains on the soil, the lawn grass does a pretty good job controlling it without chemicals.

Bermudagrass invasion because of line trimmer damage from edging badly

            Bermuda grass grows as a weed in a lawn when shade is gone. Shade disappears when the lawn dies or is damaged. Lawns die because of irrigation, disease or insect problems. When these dead spots appear in the middle of summer and the dead grass is removed, dormant Bermudagrass will grow. When lawns die in the middle of summer, do not remove the dead grass until it is time to reseed or sod these dead spots.

This is a weird shaped lawn to try and irrigate. You can't irrigate it well. Lots of wasted water. This lawn is during winter. The bermudagrass is brown because it is dormant. The fescue is green because it can handle cold. Bermudagrass invaded the weaker part of the lawn due to irrigation problems.

            Check the irrigation system. This is the most common reason lawns die or are damaged during our summer heat. Fescue remains in shady, wet spots. Bermudagrass invades dry areas in full sun.

Bermudagrass invading fescue lawn because it was mowed too short and the irrigation was not installed with even distribution of water

            Lawns are damaged when they are mowed too short. Lawns mowed below one and a half inches are too short and encourage Bermudagrass invasion. Line trimmers that cut the grass around sprinkler heads because the heads are too short damage the lawn and encourage Bermuda to grow in these locations.

            Spraying any present day weed killer in lawns that kills bermudagrass will either turn the lawn grass yellow or kill it. There is no magic bullet yet.

Keep bermudagrass from invading your lawn by:

• mowing it tall to produce as much shade on the soil as possible
• prevent damage like diseases or insects from killing the lawn in large patches so sunlight can trigger bermudagrass invasion 
• Avoid edging a lawn with a "bevel" cut with a line trimmer. Use a steel edger or line trim without the bevel cut
• When grass dies in the summer leave the dead grass in place to shade the soil surface until fall when bermudagrass grows poorly then fix the lawn

Boxelder Bugs Without Boxelder Trees?

Q. I found 50 to 100 of red and black beetles running around the rocks in my yard while I was pulling weeds. If these numbers are representative, I must have thousands. A friend thinks they may be Boxelder Bugs but I don’t have any Boxelder trees in my yard. The pictures of Boxelder Bugs online are similar but do not look exactly like these. So what are they and should I declare war on them and begin spraying?

Western boxelder bug

A. I was confused at first when I first saw these same bugs because I also thought they were Boxelder Bugs. But they acted differently from those back East. In fact, they are Boxelder Bugs. There are Eastern and Western Boxelder bugs. They look similar but are slightly different from each other.

            In the East these critters prefer trees like Boxelder, Maple and Ash. There they are more of a nuisance to homeowners than a problem. In the Western United States, they are thought of the same way; more of a nuisance than a problem. But they can pose a problem with fruit trees and in backyard orchards if their numbers are high enough.

            Here they may feed and associate with ash trees in landscapes but we see them in backyard orchards as well, particularly if mulch, either wood or rock, is used to cover the soil surface. They stay alive during the winter by finding some cozy place to congregate in the mulch when it is cold. It is here they “hibernate” until warm weather and food reappears.

            They can be a nuisance in fruit trees, and possibly damage young and older fruit, by their feeding. They feed on plants the same way as squash bugs, leaf footed plant bugs and stinkbugs. They suck plant juices out of soft tissues, leaf and fruit (the softer the better), with a long hypodermic needle-like mouthpart. Seems awkward to have but they tuck it across their belly when it's not being used.

            When they find leaves or immature fruit for feeding they pull out it out like a drilling rig and stick it in soft leaves or fruit. The feeding punctures and damages soft plant tissue. Sometimes it can be responsible for some disease problems. Expanding leaves become deformed and fruits dimpled as they grow. If the attack is severe or the attacked part very young, the leaf or fruit may drop from the plant.

            Their damage is most noticeable in pears, apples, plums, peaches and almonds. They normally don't create noticeable damage to ornamental trees or shrubs so we ignore them. Spraying chemicals is not worth the benefit or environmental trade-off unless their levels are sufficiently high and the damage is causing problems.

Mexican Bird of Paradise Fall and Winter Care

Q. My Mexican Bird of Paradise was gorgeous this year, the best ever. The flowers are now going to seed pods. Should I cut the plant back? I am wondering the proper way to care for these plants as we move in to fall and winter.

A. There is some confusion about plants we call “Bird of Paradise”. If you are from southern California or the warm subtropics you may think of the “fleshy” leaved Bird of Paradise with rainbow colored flowers. These flowers grow at right angles and look a little like the beautiful beak of a bird.

Bird of paradise flower

Don't confuse our cold tolerant bird of paradise with this one...winter tender African bird of paradise

            In the tropics, and warm, lower elevations of the desert, we may think of the Bird of Paradise as a “feathery” shrub with beautiful red, orange and yellow flowers that frequently freeze to the ground during many cold winters here.

            But in the colder parts of the desert the most reliable Bird of Paradise is similar to its feathery cousin except its flowers are all yellow. This one, the Desert Bird of Paradise, is native to Northern Mexico, Texas and New Mexico and is the most cold tolerant of the bunch.

Bird of paradise can grow in some nasty places. It looks much much better if the soil is improved, irrigated when it needs it and pruned correctly.

            Like most other landscape plants, fertilize the feathery Bird of Paradise once in late winter. Watch the watering of these plants they both tolerate poor soils but not watering them too often. They don’t like “wet feet”.

            There are a variety of ways to prune this plant. It is extremely resilient. The only thing I have seen done wrong to it in years past by landscapers has been pruning it into a “gumball”. You definitely don’t want to do that.

            If the plant looks good and you like it, leave it alone. The red one, Mexican, will freeze to the ground occasionally and grow back fuller than it was before IF it is watered and fertilized correctly.

            If these feathery plants are getting too tall, next early February cut the offending stems back to a foot or less and let them regrow. Pruning them back like this forces them to act just like they froze back to the ground. Each cut will make two or three new stems that will be shorter than the original and the plant will be denser with more flowers.

            Fertilize it with a rose type fertilizer, to favor flowering, in February and lightly water the fertilizer into the soil. Don’t put it too close the stems or the fertilizer “salt” might damage them.

            If you don't like the seed pods. remove them. Energy going into growing the seed pods will end up favoring some other plant growth like more flowers, longer stems or bigger roots.

            Right now just remove the seed pods if you don't like them. Let it go until January or February. At that time, prune it if you don't like its size, shape or density. Don't prune it if you love everything about it.

Peach Leaves Dropping Mid-Summer

Q. I planted a Mid-Pride variety of peach in late spring. Didn't really start showing signs of stress until late summer. I believe it was getting sunburned and it had messed up bark. I cut it away after one branch died. Shortly after this, even though the bark appeared to heal up fine, the leaves started turning yellow and red and dropping from the tree and its getting worse.

A. Mid Pride peach is excellent for our climate and has terrific flavor. The development of red and yellow leaves in peach during hot summer months, and then dropping from the branches, might be the variety of peach, it's tolerance to summer heat or irrigation, particularly if it misses an irrigation.  

This peach went through drought in mid summer just as the reader talked about. Some of the leaves turned red before they dropped.

            Some varieties develop only yellow leaves that drop from the tree while other varieties may develop red and yellow. Think of various fall colors in shade trees. The peach variety called Earlitreat for instance commonly drops its leaves after harvest in May but comes back again and produces the following year.

            Missing an irrigation on peach, short term drought, can also favor a disease called shot hole fungus. In our hot, dry climate this disease seldom becomes a serious problem. It attacks the leaves here but seldom attacks the fruit, unlike in more humid climates like peach-growing regions of California.

Shot hole or shothole fungus disease on peach leaves.

           

Another picture of shothole fungus or Coryneum blight.

When leaves drop it is usually followed by a flush of new growth. This flush of growth is a normal response of any tree when dropping its leaves unexpectedly. However, after dropping the leaves it is important to water normally and not water more often. Watering more often, thinking the soil is too dry, can cause some serious problems to the tree if the roots cannot “breathe”.

            Trees can have a shortage of water for other reasons than not enough water in the soil. Anything blocking the flow of water from roots to the leaves can cause the tree to act like there is not enough water in the soil. It does not necessarily mean that you are not giving the tree enough water.

            If there is severe damage to the trunk and limbs preventing water from reaching the leaves can also result in drought. Damage from borers feeding just under the bark of limbs can cause this limb of the tree to act like it is not getting enough water.

            Drought caused by the feeding of borers inside limbs will cause one or two limbs to die during the heat of summer. Before they die, leaves may turn yellow or red. Trees affected by short term drought usually put on new growth after the leaves drop and water is restored.

            Unless you are seeing some actual limb death I would not pay too much attention to it. Assume it may be a temporary problem with your peach growing in our climate. Let's see what happens to it over the next couple of years. If the fruit was not good I would tell you to pull it out and replant with a different variety. But I know this is a good peach variety.

Palm Fronds Do Not Fall From Tree Normally

Q. I am chairman of building and grounds at a church where we have palm trees which are about 40 feet tall. These trees have skirts of dead fronds below the green tops. Somebody told me if we wait long enough these dead fronds will simply fall off and we won't have to trim them. Is this true?

A. No, it is not true unless a very strong wind blows them off and you are prepared to have them look “ratty” until the rest of them blow off. Normally they hang from the palm trees in a “skirt” that can be very attractive if left fully intact but can harbor birds and rodents. It can also be a fire hazard.

Most palms hold on to their fronds unless they are physically removed, strong winds blow them off or they burn. When they remain, these dead fronds are called a "skirt".

            At the best, your church has the expense of removing dead and dying fronds every couple of years if they can tolerate some dead fronds in the canopy. Otherwise, pruning must be done annually if they are to look their best.

The base of the palm frond remains attached to the palm tree trunk unless removed by pruning, strong winds or rotting.

            Another problem of many palms are the seeds they throw everywhere each year. Have palms pruned the same time they flower and the flowering spikes that produce seed can be removed at the same time. This eliminates the problem of palm seedlings growing everywhere.

Roses Suffer in Summer, Thrive in Winter in Vegas

Q. My roses did not do well this summer after a spectacular spring. Now there are black spots on the plant's leaves.  I was told this is "black leaf" disease. What should I do now? They also got that white fungus when we had all that rain.  

(Pictures were not submitted)

A. Summers are our “winters” for roses here in Las Vegas. They don’t grow well during our very hot summer temperatures. They like the cooler spring and fall months and even the winter months if planted in warm, protected locations. They do wonderfully here for about 8 months of the year.

Rose plant growing in rock mulch. Sooner or later the rock mulch will ruin it.

            We don’t usually get black spot disease on roses here because we are so dry. I sent you a picture of this disease on roses and I will post it on my blog as well. This disease is more common in humid climates. 

Read about black spot disease of roses by Rosarians 

            This is a fungal disease and so watering roses with drip irrigation, not overhead spraying, usually corrects the problem as well as eliminating powdery mildew disease (that white fungus you mentioned on the leaves). It also helps if roses are grown in the sun, not shade, for 6 to 8 hours every day. Morning sun is best.

            Keeping roses healthy helps fight disease and damage from heat and sunlight. It also helps if air can move easily through their canopy which helps control leaf diseases like black spot and powdery mildew. Pruning roses lightly during summer months helps keep their canopy open.

            Roses growing in the desert like compost applied beneath them to improve the soil and wood chips applied after that as a mulch. Apply compost around the base of roses in January and cover the soil with 3 to 4 inches of wood chips instead of bare soil or rock. This makes a huge difference in the performance of roses.

This is a fruit tree but fertilizing roses are done the same way. Keep it away from the trunk when applying compost because some composts are "hot"

            Compost is also great fertilizer. This same 1-inch layer of compost applied in January will also fertilize them until about April. Use a follow up rose food in late spring and again in the fall months.

            If you are convinced this problem is black spot disease, then pick up a rose fungicide that states it controls black spot on roses and apply it according to the label. Repeat applications may be necessary to protect any new growth from getting this disease.

Powdery mildew disease on rose

            The white powdery fungus you saw was probably powdery mildew. This tells me your roses may be growing in some shade. Shade, and watering with overhead sprinklers, keeps the leaves wet, a perfect environment for powdery mildew. Splashing water from overhead irrigation sprinklers spreads the disease from leaf to leaf and plant to plant.

Read about powdery mildew on roses by Rosarians

            Prune out unhealthy growth now, getting rid of diseased plant parts, and leave 4 to 8 healthy canes for further pruning this winter.

Figs NOT Low Water Use Plants

Q. I have a couple of fig trees that are 4 to 5 years old which have some problems. They produce a lot of fruit during the year but the fruit gets about grape size, turns yellow and falls off. Both trees are watered twice a day during the summer. The soil appears to be moist every time I check.

Readers fig tree

A. Your fig trees are very nice-looking looking at the picture you sent. However, the irrigated area under the tree, about 18 to 24 inches across, does not look big enough to support four-year-old fig trees. I don’t think you can put enough water under the tree to keep this tree producing figs until they are mature.

Fig tree in the winter. Fig tree was 15 years old and kept at 7 to 8 feet tall. Very productive but need lots of water.

            I’m sure it’s quite confusing. You have a very nice-looking tree, you are watering every day, but the tree doesn’t produce any edible figs. So it can’t be a watering problem. Right?

            Wrong. Even though you water every day, if not enough water is applied then the fruit may fail to develop even though the canopy looks great! Leaf and stem growth is greatest early in the year when temperatures are cooler. Fruit develops when temperatures get hot.

            Watering daily may have nothing to do with the amount of water applied. Fig trees, or any plant for that matter, doesn’t care if it gets water every hour, every day or every week. The total amount of water applied must be enough to satisfy its needs.

If you want figs like this then you really need to pour the water on during fruit enlargement. This is FULL of water to get this big.

            Fig trees use a lot of water. The amount of water required in a week increases 500% from January to July. If you want fruit from these fig trees then they must get enough water while the fruit is developing. If they don’t, the fig fruits will be small and/or drop from the tree.

            Increase the size of the area where water is applied to at least 4 feet in diameter. 6 foot in diameter is better. Add additional drip emitters so the tree gets more water each time you irrigate. Avoid increasing the number of minutes on your irrigation timer.

This irrigation basin..well...around the tree might be big enough when it is small but NOT when the tree gets bigger.

            Trees do not like to be watered every day. Water fig trees three times a week in midsummer but each time apply about 30 gallons. That is 90 gallons a week in midsummer. The tree should have enough drip emitters around it to wet the area in a 4 to 6-foot diameter under the tree.

            The total amount of water delivered in a single application should be about 30 gallons. Put a 4-inch-deep layer of wood chips under the tree about 6 feet in diameter to help keep the soil moist between irrigations.

            Please realize you can water every day and still not give plants enough water. Watering frequency does not necessarily mean watering sufficiently for the plants needs..

Not Thrips on Grapes. Leafhoppers!

Q. Some kind of thrip-like bug has invaded my garden. My grapes leaves are brown and drying up from these bugs. There’s tiny black spots where they were. There’s so many of them I can hear them as I approach the plant. I applied Spinosad in September but it didn’t do anything. Now they’ve gotten into my peach tree.

A. The tiny black spots on grape leaves is fecal matter (poop) from leafhoppers, not thrips. Thrips are very common on grapes here that feed on plant juices from the leaves of grapes and other plants.

            Leafhoppers start building their colonies in grapes around April. Once established, they will build huge colonies in the grapes and spread to other plants.

grape leafhopper damage

            They are easy to get under control in April and May when they are young. They are extremely difficult to control without some heavy duty insecticides later in the season.

            Spinosad, a natural insecticide spray, works great if applied early in the season such as April and May. Later in the season you will need to bring out some heavy duty artillery to get them under control.

Leafhoppers greatly magnified. They are maybe 1/8 inch long

            I hate to recommend anything this late in the year because the insecticides needed are very heavy-duty. It is best if you can wait until next spring and begin treatment early with Spinosad or pyrethrin sprays.

Spinosad active ingredient

            Alternate Spinosad with insecticidal soap and neem oil. Make sure to spray the tops and bottoms of the leaves. If using Spinosad, two sprays about six weeks apart starting in late April will take care of them, the hornworms and the skeletonizers all at the same time.

Sooty Canker Disease Not Always Lethal

Picture of Chinaberry from Reader

 Q. Help me decide if I can keep my 12-year-old Chinaberry tree. I fear it has sooty canker disease because it has some branches dying. But it does not have peeling bark. It is a joy in the spring with all the flowers and I would like to keep it at least one more spring if this disease does not spread to other trees

Picture of Chinaberry from Reader

Picture of Chinaberry from reader

A. Regardless of whether you keep it or not, the tree needs to be pruned at the least to remove the dead branches. Once the dead limbs are removed and examined it will be easier to find out if it is actually sooty canker disease. If this disease is confined to limbs and does not enter the trunk, it is possible to save the tree.

            Sooty canker disease attacks many different plants but seems to favor mulberry, poplar or cottonwood, apple trees and yours. It is called sooty canker because the dead wood, just under the peeling bark, is covered with a black powder that looks exactly like a heavy layer of soot from a fireplace chimney.

Actual sooty canker on apple

Actual sooty canker on apple

            This disease enters the plant through limbs damaged by the intense sun, pruning with hand shears or chainsaw and wounds. It may be taken from tree to tree by birds but the most common means of spreading this disease is with dirty pruning equipment.

            When pruning, make sure saw blades are sanitized BETWEEN cuts with diluted bleach or Pinesol. It is possible to save the tree by carefully pruning out dead branches but making sure it is not spread by equipment through cuts.

            Sooty canker usually attacks weaker trees so make sure the tree is receiving enough water and is cared for properly with a single fertilizer application each year in early spring.

            Yes, you could prune now with no problems or in the spring. This disease does not spread quickly. But if the disease is in the trunk it is a goner. If just in the limbs, it is possible to save.

Viragrow Delivers! : Composted Chicken Manure: a Solution for Nematode ...

Viragrow Delivers! : Composted Chicken Manure: a Solution for Nematode ...: This is difficult to to read unless you have a  background in writing scientific journal articles. The reason I included this summary is ...

Viragrow Delivers!

2016 Pest Pressure on Vegetables from U of AZ

Just a warning for home and backyard gardeners. This is focused on commercial producers. Voice only and you should be somewhat familiar with the names of plant pests. He talks about whitefly populations, Bagrada bug (African Painted Bug, a relatively new pest for us), Diamondback moth, loopers, etc. Still a good inventory of plant pests in the deserts of the US Southwest.
 
https://www.youtube.com/watch?v=H64F8GINQOA&feature=em-subs_digest