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.

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.

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.

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..

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.

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 …: 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!

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

Q. It has gotten down to 30 degrees overnight here in Boulder City, NV. I’m worried about my little 6-foot lemon tree (in a 5-gallon pot on the porch). So I placed a queen-sized bed sheet over the tree, and hung a 100 watt incandescent lamp from a branch last night. I’m hoping that small amount of heat will raise the temps above freezing. Is this necessary? A. There are some different reasons and different temperatures that will affect citrus in different ways. Remember that low or freezing temperatures have two components; the low temperature you reported of 30F and its duration or how long that freezing temperature lasts. The longer a damaging temperature lasts the more damage it will do. Meyers Lemon is more tolerant of freezing temperatures than other lemons. Hanging a light bulb that gives off heat will help a tree if there is no wind or the wind is blocked. If there is wind present then heat from the bulb helping is questionable. Covering a tree with a sheet or burlap helps keep the wind off of the tree and may trap some warm air under it for a short time. If the cold lasts a long time, then eventually the air under the sheet will get to the same temperature. Again, it’s a matter of duration. The more insulating properties this cover has, the better it will be at keeping that temperature from dropping. Open flowers, young fruit and new growth are the most sensitive parts of any fruit tree. Open flowers of any fruit tree, whether the fruit tree itself can withstand -20F or 32F will always be damaged if not outright killed when temperatures hit 32F for very short periods of time. If your tree had flowers that were open AND the temperature around those flowers hit 31F for 30 minutes, the flower and any fruit it could have produced are dead and gone.  Unopened flowers and young fruit are slightly more tolerant of freezing temperatures but not much. If the temperature dropped to 28F for 30 minutes, very young fruit will be killed and these will drop from the tree. Larger fruit require lower temperatures but still can be damaged depending on the “antifreeze” (sugar content) of the fruit.  New growth will be damaged just below freezing as well. This is why I tell people NOT to fertilize winter tender plants during the second half of the summer. Established trees are a bit different. Each type of fruit tree has its own special tolerance to freezing weather. All citrus is generally tender to winter freezing temperatures. They are considered “semi-tropical”. This is why growing citrus in the Las Vegas Valley is generally considered risky. Young citrus are damaged more extensively at the same freezing temperatures than mature citrus. Mature citrus has more “mass” and so it can withstand the same freezing temperatures that might kill a young tree of the same kind. Instead, larger trees will get some damage but they will grow back from that damage. So to answer your question, yes, the light bulb helps. Keep the bulb from burning leaves and stems. But ultimately it will depend on how windy it is, the duration of the freeze and how insulated the cover is. It is best if the cover reaches the ground so that as much warm surfaces can radiate heat back to the tree as possible.

Q. I have vegetable garden. Do I have to cover with a sheet if it freezes?   A. It depends on the vegetables and the site. Vegetable gardens located in warm areas of the yard with reflected heat and very little wind are much warmer. They may not need to be covered or covered less often than those that are exposed. Vegetables growing in these locations are not as likely to freeze during the winter. Freeze damage to tomato plant Freeze damage to tomato fruit      Of course any of the warm season vegetables like tomatoes, peppers, eggplant, squash, etc. are going to freeze as soon as temperatures drop below freezing. In fact, they can suffer some damage when temperatures drop to the temperature of your refrigerator.             Some warm season vegetables like beans may freeze to the ground at the hint of a freeze while others like peas, spinach and radishes may sail through the winter with no problems. Sorry that I can’t give you a definite answer on that because there are so many variables. Bush bean collar rot due to cold soils             To be on the safe side get yourself a 1 ounce or more frost blanket and cover your growing area when temperatures are predicted to drop below freezing. Depending on the frost blanket, it can allow 50% or more of the light to reach the vegetables and it also breathes while it can raise the temperature under the blanket five or 6° F. It also keeps the wind off of the vegetables. Crop cover (frost blanket) on raised bed for improved germination during cold weather             Follow the direction and tack it down tightly so the wind doesn’t get under it. Or put some weighted objects along the perimeter of the blanket. Don’t use burlap or plastic sheeting. Spend the money, buy the 1 ounce or heavier frost blankets and they will last for three or four seasons or more. De Witt makes a good one. So does Agfabric.