Q.  All my roses face north, and some are against a cinder block wall. They get no shade and they really struggle with our summer heat. Most will have to be replaced. I am already looking at roses to plant for next summer. Do you know any varieties that can withstand our summers? Also, how does Crepe Myrtle handle our summer heat? A. If your roses are on the north side of a building then they may get direct sunlight late in the afternoon because of where the sun sets in the summertime. That late afternoon direct sun can be very damaging if they have been going on the shady north side all day. Healthy plants handle heat better. Plant both in soil amended with good compost. Roses growing in the desert should not be planted surrounded by rock.             Somewhat tender plants to our desert climate, like roses and crape myrtle, handle the intense desert heat and sunlight if they are growing in soil amended with organics and the soil is covered with mulch that rots or decomposes. Roses and Crepe Myrtle will struggle after a few years when planted in soils covered by rock. If you want them to look good in years to come, roses and Crape Myrtle should never be surrounded by rock mulch. Ever.             Always plant in soils that are amended with a decent soil amendment like compost. After planting, always cover the soil with mulch that rots or decomposes such as woodchips. The woodchips on top of wet soil will decompose. Fertilizing these plants appropriately keeps them healthy, the leaves green and vibrant.             It might be a good idea to provide some shade from that intense sunlight late in the afternoon. Plant a medium-sized shrub or build a pony wall in this location to provide a less intense microclimate for their growth.             A list of roses that perform best in desert climates can be found on the Weeks Roses website located at www.weeksroses.com in the column titled, “Roses by Climate”.

Q. I have several fruit trees planted around my fire pit near a waterfall and pond.  I bought a Murcott tangerine which has not grown an inch in 2 ½ years and the tiny fruit it produces falls off by summer. All the other fruit trees are doing fine except for this tangerine. Murcott mandarin orange from reader A. This citrus produces fruit ready to harvest from January through March. It originated from central and southern Florida and does best in locations where freezing is rare. Any freezing temperatures during the winter and early spring may cause the fruit to be inedible. I hope it’s planted in a warm microclimate. Same Murcott Mandarin orange.              Problems like these, when similar plants are growing together and one does poorly, is usually a problem with the soil or how it was planted. Possibly irrigation. During the winter carefully lift the tree from the ground by severing the roots with a sharp shovel and lifting the rootball with two shovels on opposing sides. Gently wash the soil from the roots and put the tree in a clean bucket of water, covering all the roots with fresh water. Citrus Harvest Dates University of Arizona             Re-dig the hole so that it’s five times wider than the tree roots taken from the ground. If water drainage was a problem, the tree should be planted about a foot higher than the surrounding soil. Do not use the same soil but replace it with a soil mix amended for planting. Murcott Orange Info UCR             When planting the tree in this hole, the roots should be less than ½ inch below the finished soil surface surrounding the tree. As soil is added around the roots, add water from a hose to remove any air pockets. Do not step on the soil with your feet but use water to settle it around the roots. Remove about one third of the canopy of the tree after planting. Stake the tree so the lower trunk doesn’t move for one growing season.             If the soil mix was made with a rich compost, no fertilizer is needed for one or two growing seasons. Otherwise, apply a fertilizer to the soil high in phosphorus when planting. Next spring place fertilizer 4 inches below the soil and about 12 inches from the trunk with a shovel and water it in.

Q. A second crop of mini-melons I planted split before it was ready to harvest. I think it was the heat because the first crop using same seeds ripened on the vine. These have a mild taste but not very sweet. Is there a “sow by” date so they will ripen before it gets so hot? A. Melons split before they are fully mature because the soil becomes dry and then watering or rain occurs. The result is burst or split fruit because the fruit swells. This happens with many kinds of fruit, not just melons. The seed inside the fruit may be mature but the fruit hasn’t yet finished ripening before it splits. Blood orange fruit split             When a plant is not getting enough water, but the soil begins to dry, the fruit will either abort early or the plant will try to finish as much ripening as possible before the water runs out. This early ripening due to a lack of water can affect the sugar content or its sweetness, the quality of the fruit, the size of the fruit or all three! Kara Gul pomegranate split and interior rotted             When the plant is not getting enough water and begins ripening the fruit, but the soil gets extremely wet again, water is pumped from the roots into the fruit and it splits. The fruit might not be fully ripe, but the seeds are oftentimes mature enough to grow. Applying a thin surface mulch to the soil or growing a variety that shades the soil better and retains soil moisture may reduce fruit splitting during the heat. Also, using a plastic mulch when growing vegetables helps retain water in the soil and reduces splitting. Myers lemon fruit split             The sweetness or quality of the fruit depends on many things, but weather and climate are major factors. In fruit and wine culture, this is called the “terroir” of the crop. Therefore, some varieties of fruit produce better quality fruit than others in the hot desert versus coastal California. Try a different variety of mini-melon next time, particularly one that has parents which performed well in hot climates. Nubiana plum fruit split             Most of the seed packets tell the days to harvest. If the soil is kept moist, the days to harvest should be accurate. However, add five days to this number if harvesting a fall crop that is normally grown during the spring and summer months. 

Join me in an explanation about the role of organics in desert soils and their impact on applied fertilizers.

Q. We planted a butterfly bush that was doing good but suddenly took a wrong turn! I’m very grateful for any help and guidance! Sorry. I dont have a picture of a butterfly bush growing in the desert. A. There are problems, sometimes, using the common names of a plant. Do me a favor and Google “butterfly bush”. If what you are calling butterfly bush is “Buddleia”, then you have a bush that struggles in hot desert climates unless you keep it out of the afternoon sun. You must improve the soil around this plant at planting time and never plant it in rock, a.k.a. desert landscapes.             This is a shrub that grows well in Chicago, Illinois. It can be planted as far south as Atlanta, Georgia, so it probably will flower this far south, but I have never heard of it planted in the hot, desert Southwest. In our climate, plant it on the east side of a building where it gets shade in the afternoons. If you planted this shrub in the wrong spot, baby it through the heat of the summer and move it to a new location in October.             Plant in soil amended with compost. Use woodchips at the base of this plant in a circle at least six feet in diameter. Water it to a depth of 12 – 18 inches and use 4 to 6 drip emitters after it becomes established. Two emitters should be enough for the first two years. Watering frequency would be the same as fruit trees and other non-desert landscape plants.             This shrub is beautiful when it flowers. It flowers on new growth so it’s best if it’s pruned to the ground during the winter of each year after it is established. Its floral display depends on the plant vigor, fertilizers applied and its overall health. Apply iron fertilizer along with a fertilizer used for roses in late fall just before leaf drop or very early spring.

Q. I was thinking of using soaker hoses around my trees instead of drip emitters. Any advice on that? Drip tubing has emitters embedded in the walls of the tubing. A. You are calling them “soaker hoses” but I prefer to call them “drip tubing”. Drip tubing is about half inch in diameter with drip emitters embedded in the tubing walls during its manufacture. Its best use is in areas that need water applied evenly to the same depth, repeatedly. Drip tubing emitters release a precise amount of water at precise distances apart.             Drip emitters are added to “blank tubing” (no emitters in the sidewalls) after it’s installed. It’s best for watering individual, smaller plants with spaces between plants that should stay dry. Drip emitters are best for watering different kinds of plants of different sizes with varying amounts of water. Drip tubing must be under a precise pressure, psi, to work properly.             Drip tubing is ideal for watering trees over 20 feet tall. A coil of drip tubing can be placed under the canopy of a tree and enlarged as the tree gets bigger. The embedded emitters in drip tubing should be 12 to 18 inches apart under the canopy of the tree. The length of tubing needed depends on how much water is applied. When water is applied under medium trees, it should penetrate 18 – 24 inches deep. When water is applied under large trees, it should penetrate 24 – 36 inches deep.

Q. I planted two Mandarin oranges from different nurseries this past spring.  One did very well in full sun from the git-go. The other had leaves that were turning yellow.  I applied iron and nitrogen fertilizers, but it didn’t do much after a week. So, I constructed some shade over at and it started looking green again. Sometimes plants need to “acclimate” to their new desert climate.   A. It sounds like you’ve got your answer; intense desert sunlight caused leaf yellowing. But it begs the question, “why only one of the trees if they were both mandarin orange?” You said the trees came from different nurseries. That might be part of the answer.             But first, eliminate other potential problems before I get to the nursery explanation. Make sure your trees share the same microclimate, the soil in both locations was similar with similar drainage, the soil mix used to plant both trees was the same, that the roots were kept moist and planted no more than half inch below the soil surface, that they were staked and watered thoroughly after planting. Sometimes yellowing on citrus can be for other reasons.             You may be observing differences in how and where your trees were grown versus our harsh, desert climate. A local nursery used to bring in citrus trees for sale in containers and put them in an area that had partial shade. They could put them in full sun and sell them from there, but they didn’t. Too risky. Sometimes yellowing can be from high light intensity.             Plants grown in a greenhouse, under partial shade or in a cool, coastal climate produce leaves that are different from leaves grown during our harsh desert sunlight and low humidity. When tender plants are plunged directly into our strong sunlight and low humidity, the leaves may scorch, yellow or drop from the plant. The plant is not dead but quickly produces a new set of leaves very different from its old ones. The newer leaves are smaller, thicker, tougher and better capable of handling desert sunlight and humidity. The plant has become “acclimated”. Yellowing from an iron problem happens on new growth and lowers the health of the plant making it more susceptible to heat problems.             Observe where nurseries are selling plants. Plants sold from shady areas may struggle when planted in full sun. Plants grown in a greenhouse need two or three weeks of “acclamation” before they are plunged into an intense desert landscape. This is true of vegetable transplants as well.             If you suspect you have a plant which may be acclimating to its new environment, sometimes it’s easier to strip off the leaves or prune the plant so its new growth is better acclimated to its new desert environment. In your case, wait until fall and remove the shade. Let the mandarin orange “acclimate” to its new home during the cooler fall weather.

Q.  We have lots of aphids in our good-sized oak trees that are dropping sap on our cars and the sidewalk. Short of cutting the trees down, do you have any suggestions on how to get rid of the aphids? Not from the reader but aphid sticky exudate on oak. A. Blame their high population number s this year on our wet and humid spring weather. The fastest and probably cheapest way to get rid of them is to drench the soil beneath the tree with a systemic insecticide diluted in a bucket of water. This dilution will help you spread it more evenly everywhere under the tree. aphids on pomegranate             The pesticide I’m telling you to use has the active ingredient imidacloprid in it. This insecticide is systemic so when you pour this around the base of the tree, diluted in water, the roots will take it up and transport it to the leaves. Since the aphids are sucking juices out of the leaves, they ingest this toxin and die. Leaf curl on plum from early feeding and leaf expansion             There are several trade names of this pesticide that contain imidacloprid. The most popular with homeowners is the Bayer product with the trade name “Tree and Shrub Insect Control”. Any product that you use must contain imidacloprid in the ingredients. The easiest and probably safest way to apply it is a “soil drench” but it can be sprayed on the leaves as well. One of the many products that contain imidacloprid. It is now the most used insecticide in the world.              The label will tell you how much of this pesticide is applied to one tree. Follow the directions on the label for a soil drench application. When you are finished with the application, rinse the bucket three times with fresh water and apply these “rinsates” under the tree as well. Wear unlined plastic gloves and eye protection when mixing and applying this product and rinse, or dispose of them, afterwards. Chitalpa black aphid             Consider spraying these trees during the wintertime, from top to bottom, with a dormant oil. Apply an extra dose to the base of the tree where aphids might be hiding. Dormant oil sprays applied during the winter are very effective in reducing the populations of aphids, scale insects and spider mites for the next growing season. Entrance to an ant colony on the orchard floor.             Ants love aphids. They “milk” ants of this sugary sap for their own use. If you look at the tree trunks carefully, you will see a steady stream of ants going up and down the trunk. They are also part of the aphid problem and should be controlled. Follow the stream of ants back to the opening of the underground nest. Sprinkle 10 or 15 “crystals” of ant bait directly at the opening of the nest. I use a product called “Amdro”. The nest will be empty the next day.

Join me in this episode of Desert Horticulture. I discuss the grasshopper invasion, those giant wasps that have been flying around and the fruit salad tree. Is it any good?

I received this recipe for pear tomato jam I thought might interest some of you.  For many years I helped my mother canning, storing, and making jams and jellies for a family of six. I finally quit making jellies about 4 years ago. I liked making jellies from strawberries and crushed pineapple; Apricot and pineapple; and Yellow Pear tomato with pineapple.   My own recipe: 4 cups tomatoes crushed ( I have a 30+ year old Oster chopper 1 8 oz can crushed pineapple Combine to make 5 cups of fruit (you may need a small amount of water 1-2 teaspoons lemon juice which keeps the jelly from turning dark 7 cups sugar 1 package pectin Follow the Pectin instructions. Keep up the good information Loretta