Question:My next door neighbor cut down large pine trees that shaded my wall of star jasmine two days ago. Is there any point trying to rig a shade cloth to get through the rest of the summer hoping they can "harden off" to full sun or should I basically pronounce them dead and start the grieving process now?
Answer:Star jasmine can handle full sun if it’s planted in good soil. But you are right, it will probably go through some shock to have it this exposed to the hot sun at this time of year.
These plants will probably have some leaf scorch and some dieback as they transition to full sun. But I think it will rebound. You may have to cut the damaged parts back, fertilize it in October and let it regrow. At this point, I would wait and see what happens.
Plant health has a lot to do with how plants handle hot weather. Plants that are not as healthy will have more difficulty during hot weather than plants which are in good health. In a contrast to this, plants that are not as healthy can grow in protected environments and still look good.
I would encourage you to buy some decent compost and spread about an inch layer at the base of these plants and water it in. This should improve their health. The best compost for this I found is at Viragrow in North Las Vegas available in bulk in bags. Soil improvement will go a long way in improving plant health and their ability to withstand adverse conditions.
Because of the high light intensity and warmer temperatures, they might begin to use more water in this location. I don't necessarily think you need to apply water daily in this spot but you may have to increase the volume of water 20 or so percent and maybe add an extra day of watering.
Try adding this water with a hose first but avoid daily watering if you can. Watering daily might create some problems for these plants if the soil doesn't drain very well.
If there is no surface mulch surrounding these plants on the soil surface then put a threeto fourinch layer down. Wood mulch is better than rock mulch for soil improvement. You can get wood mulch free from the University Orchard in North Las Vegas which is 100 yards east of the corner of Horse Drive and North Decatur in Aliante any Tuesday, Thursday or Saturday morning.
Question:I have a butterfly bush that is struggling. It looked wonderful this past spring but now the leaves and blooms are much smaller. There are many leaves turning black. The bush has full sun and gets watered regularly. Do you know what the problem might be?
Answer:Check for grubs (worms) eating the roots. This is a common problem on butterfly bush this time of year. Use a liquid insecticide as a soil drench to wash the roots and kill the grubs or use granular insecticide and watered into the soil. Look for one that is for grubs at your nursery or garden center.
Question:For several years my saguaro has been turning brown slowly but the process sped up this year. I have two others but neither of them has problems and seem to be completely healthy. I really don’t believe I am overwatering it but it is a possibility?
Answer:The last time I saw this kind of browning on the surface of a saguaro is in a landscape where they were wrapping it each winter in an attempt to protect it from winter cold damage. They used burlap.
It caused a lot of surface disease problems on the cactus because of a lack of air circulation. They finally stopped doing that but the damage was already done and the surface of the cactus had a lot of brown damaged areas.
I hope you are not wrapping it during the winter. If you are, stop it. Let it breathe and take your chances. I know they are expensive.
Make sure that water is applied to the surface of the soil surrounding out to a distance of six or eightfeet and water is not spraying the trunk. Do not water too often. Water deeply in these areas about every 2-3weeks. I would rather see it watered every three weeks rather than two weeks and actually three weeks is really too often.
These plants store water in their fat bodies and can live on this stored water for a long time. When water is present in the soil after a rain or irrigation the roots absorb it like a sponge, very quickly and that fat body swells up and expands like an accordion. That's why it's ribbed.
Don't wrap it in the winter time and water it deeply and not very often.
Question:I removed two Italian Cypress trees which is harder than I imagined, especially the stumps. When is a good time to replace this tree and what size hole does it require? Does the soil need any special preparation prior to planting?
Answer:I can imagine that was a very difficult job removing Italian cypress. Probably the easiest way to do it is to cut it off and rent a stump grinder and grind out the stumps. The stump grindings mixed with soil makes a fabulous mulch.
The best time to replant is in the fall months but the problem is plant selection. There is usually not much to pick from. The best stuff is gone and the nurseries don't want to be stuck with anything through the winter and availability of plants from wholesalers is limited to stuff that didn't sell. But you can still find things if you're willing to look around.
An alternative to Italian cypress is the Skyrocket Juniper. It is hard to find but stays narrow like Italian cypress but doesn’t grow as big. I have never seen any available in the southern states. They used to be popular 30 or 40 years ago.
You should not have a problem planting in the same holes if the Italian cypressremoved was healthy. Dig a hole 3-4times the diameter of the container it comes in. If the soil from these holes already have quite a bit of organic matter in them (the soil will be dark brown) then don’t add anything to the soil. Otherwise mix the soil you take from the hole 50/50 with compost.
Question:Last year I purchased a home with fourmesquite trees, a tree that I was unfamiliar with because I’m not from the area. This year I have a million or so unsightly seed pods cluttering up my rock mulch. They are very hard to pick up and I am 89 years old so. Is there anything that can be done to reduce the amount of pods these trees produce?
Answer:Sorry, but there really isn't anything you can do about the pods. It is just a biological fact that we have to live with.
An alternative might be to use a different color rock mulch beneath it. A multicolored rock mulch rather than a solid color rock mulch hides these pods a lot better. Kind of like when you pick out a carpet and you don't want to have to keep it clean all the time. You pick a carpet with a lot of colors in it and it hides the dirt and debris better.
An alternative might be to burn them with a fire weeder fueled on propane but a lot of people don't want to go that route.
Question:I have an apricot tree that produces a large amount of sucker growth from the roots, some as far as 10' from the trunk. My guess is the tree is 15 or so years old and I'm wondering if the tree is starting to decline. Is there anything that can be done to reduce the suckering?
Answer:Suckering from the roots of any tree can indicate there may be a problem with the tree itself. Look the tree over for any kind of sap oozing from the trunk or large limbs.
In any case, try to leave lower limbs on the trunk no higher than about waist height. This helps to shade the trunk from intense sunlight. Intense sunlight in our climate can burn the trunk or limbs; sunburn.
Sunburn damage can attract boring insects that attack the trunk and large limbs. If it doesn't destroy the anesthetics of the tree, painting the trunk and lower limbs with diluted white latex paint can reduce sunburn damage if this is a problem.
It can also be because of the rootstock of the tree. Fruit trees are normally grafted or budded to a totally different tree close to the ground. This results in two separate trees fused together; the top for producing high quality fruit and the bottom tree producing a high-quality root system. Some of these trees used for rootstocks produce suckers more than others. Your tree may have one of these rootstocks.
Regardless, sharpen and clean a round nosed shovel and sever these suckers at a point beneath the top of the soil and remove them as you see them.
Question:We have twoMimosa trees that we planted 14 years ago.One produces a lot of flowers and seed pods, the other very few. Over the last five years, the trees experience a lot of dying branches at the ends - maybe the last 10-15 inches.We have been hand trimming the dead stuff off. Ten years ago we had borers in both trees and we have been treating them ever since.No borers anymore. What is causing the tips of the branches to die, and how can we fix the problem?
Answer:Mimosa is a short-lived tree. At 15 years it is getting to the end of its rope. It gets a disease called Mimosa wilt which plugs up the water conducting vessels inside the branches and the branches die. This is from a pathogen called Fusarium and commonly found in many soils.Expect to replace the trees. I would not plant another mimosa there since this disease lives in the soil and planting another mimosa tree there will lead to the same result only sooner. Enjoy it while you can. When you prune the branches thoroughly sterilize the pruners with alcohol or bleach (then oil them) between cuts. The disease will be spread from branch to branch and tree to tree by infected pruners.
Question:How does a greenhouse save water? How does plant water use compare inside a greenhouse to the same plants outside the greenhouse?
Answer: Reducing water use in greenhouses. This is arguable. In many cases the opposite is true; water use is increased in the area covered by greenhouses. This is because there are typically a higher concentration of plants grown in the greenhouse than in the field. Also, plants can be grown for many months in the greenhouse, more months than in the field. A higher concentration of plants and having plants growing longer means more water is used.
The argument for reduction of water use is because the wind and humidity. There are four principal factors that govern water use in plants; solar radiation which is the intensity of the sunlight, air movement or wind, temperature and humidity. Of course there are the plant factors as well; the size of the plant, the number of plants grown and the type of plant. Some plants of the same size use more water than others. The two principal factors that reduce water use in greenhouses is the raising of humidity and the absence of wind. The two external factors that drive water use in plants the most are solar radiation and wind. Temperature and humidity are important but they are not as important as solar radiation and wind. Reducing wind is a big factor in the reduction of plant water use.
Robert Morris is a consultant, area horticulture specialist and a professor emeritus in horticulture with the University of Nevada Cooperative Extension (UNCE). His blog is Xtremehorticulture of the Desert Blog. He can be reached on Skype at RLLMorris, cell and VOIP 702-630-5173 and on LinkedIn at Robert L Morris. Email questions tomorrisr@unce.unr.edu.
