Q. The branches of my Palo Verde are turning brown and dying. I have lost one tree and looks  like two others will die as well.  They are 25 years old. A. It is difficult to diagnose without more information. If branches are dying in Palo Verde during the heat, my mind instantly goes towards borers. The Palo Verde borer that feeds on the roots is a possibility. Flatheaded Borer in palo verde limbs due to sunburn. Pruning too much can cause severe sunburn on the branches.             It is possible it could be other borers in the tree, such as some of the flat headed borers, but individual branches dying is frequently associated with borers of some sort. If you think borers might be the problem, apply a soil drench insecticide around the base of the tree and water it in. Flatheaded borer in palo verde. Be careful when you prune.             It is also possible to be water related such as keeping the soil around roots too wet. If the irrigation has been changed recently or there was an irrigation problem, too much water might be the culprit. Desert trees like Palo Verde perform very well when there is more time between irrigations compared to landscape trees like ash or even Chitalpa.             It could be pruning related. If trees were recently pruned hard this past winter or spring, there is a possibility of sunburn damage to the limbs. The limbs would be discolored or brown on the top surface facing the sunlight. Sunburn damage frequently attracts boring insects.             Make sure the tree is watered deeply but infrequently. Water applied to the soil should wet most of the area under the tree, not just close to the trunk. This water should drain into the soil 18 inches or more.Hopefully it will heal on its own. Be careful of pruning.             Wet soil is soft. Dry soil is hard. Use a long screwdriver or 3/8-inch rebar poked in the soil to determine how deep the water has moved into the soil after the irrigation.             This tree should not require an irrigation for a week if it’s watered deeply. When the soil around the roots becomes dry, this tree will start dropping its leaves. This is your signal it’s time to water again.

Q. What lavender would be best for making a hedge? I just bought a home and heard lavender is a natural repellent for scorpions and other insects. I’m trying to tackle my pest problems and landscaping renovation at the same time.    ‘Spanish Eyes’ fernleaf lavender in a five gallon container in East exposure A. I think your selection will be restricted more by what is available locally. Stay away from English lavender in hot locations. English lavender would be better planted in the north or east sides in some light shade. Spanish and French lavender are generally more tolerant of the heat.             I am not sure what local nurseries are selling but lavender has been planted in our climate without any difficulties. It is fine in full sun but it may struggle in very hot locations such as against walls west or south facing. These plants will appreciate amending the soil at planting time. Rock mulch is never a good idea with lavender. Amend the soil with compost at planting time and cover the surface of the soil with woodchip mulch. You might look for Rosemary and neem oils as a spray deterrent for bugs as well.

Why Twitter? Twitter gives you real time information about what is happening NOW.  Learn what people are asking now or what pests they are seeing. Stay on top of what is happening. https://support.twitter.com/articles/162981 Isn’t following Xtremehorticulture blog enough? Yes, if you don’t need to know what’s going on in real time. By signing up to receive my tweets you will get alerts when I post something new. Your email address is not shared with ANYONE! I post on two twitter accounts;  @Xtremehort for real time gardening information and @Viragrow, for a focus on compost, soils, soil mixes, mulch and fertilizers. Tweets include: real time alerts of local pests news about the organic movement and local food questions sent to me with pictures How to get these tweets? In your browser type in @Xtremehort and follow the directions! Same with @Viragrow

Q. I’ve a small collection of Cymbidiums, Cattleyas, Phalaenopsis orchids and staghorn fern plants. I am moving from California to Henderson. Will I have any luck in continuing to grow them after I move? What kind of different care will I need?   Orchids at our farm in the Philippines A. I have grown easy to grow orchids like Phalaenopsis and Cymbidium without any problems in the open air here in the Mojave Desert. We have them on or farm in the Philippines but that’s cheating. I have even kept them in an open atrium without extra humidity in Las Vegas during the winter without problems. I just keep an eye on the temperature and the sunlight. It is surprising the temperature and humidity extremes they can handle. Orchids in the Philippines kind of suffer through the dry season until rains come beginning in July. Tiger orchid             Staghorn fern is going to be different. Unlike orchids, they don’t require a lot of light. But they will begin to look ragged if you don’t provide them with extra humidity. Staghorn, as well as birdsnest ferns, will be difficult to keep looking good without some control over humidity. You might consider a humidifier in the room where you keep plants more sensitive to humidity. Angel orchid             Use distilled water spiked with a small amount of fertilizer when you water. Check the salinity of your irrigation water and keep the salinity below an EC of 2.0 mmhos/cm (dS/m) when you water any houseplants.             Our tapwater coming from the Colorado River has high salt levels that could damage sensitive plants if they are watered with it regularly. Never mist them with it. Likewise, it’s not good to water plants with straight distilled or RO water.             There is a local group of orchid growers that you could reach out to called the Greater Las Vegas Area Orchid Society. They can be found on the Internet at http://www.glvos.org/

Q. What is the proper care for Canna lilies. Since they are a dominant plant in my landscaping here in Palm Springs, I’d like to know what to fertilize them with, when to fertilize, when to cut back, when to water, how much and in which season, etc. I read your information on deadheading and that was useful. Take a look at Canna lilies on Pinterest https://www.pinterest.com/pin/14144186308774982/ A. I like Canna Lily as well. There are many types to pick from; different heights, flower color, leaf color, leaf variegation. One thing is for sure; these plants love lots of organics in the soil and plenty of water. They grow even in fish ponds!             Plant them in a high, water use areas of the landscape together with other plants that like lots of water. They can take full sun as long as they get plenty of water and great soil. Make sure their soil is amended with lots of compost at planting time. They love the surface of the soil surrounding them covered with woodchip mulch, not rock mulch.             If they are growing well and robustly, they need to be dug up and divided every 3 to 4 years. Do this at the same time as you would iris; when it cools off in the fall or very early spring. Fall is best. Divide them at this time, wait a few days to heal and replant them.             Deadheading is always important for looks and continual blooming. Fertilize them 3 or 4 times during the year with a rose type fertilizer; very early spring when new growth is pushing, lightly during the summer months at about half rate, late summer when it begins to cool and once more around Halloween.             To help you remember it think of Labor Day, Fourth of July (half rate), Memorial Day and Halloween. To get vibrant Cannas, substitute compost instead of fertilizer for the first or last application of the year.             Cut them back to the ground after they freeze in December or just before new growth if they don’t freeze.

What’s happening to my Spring Bouquet (Viburnum Tinus)?  It bloomed beautifully in the Spring for several years (including this past Spring), but many of the leaves are turning brown, and appear to be burnt.  I didn’t see any evidence of spider mites or other pests.  I checked the drippers and it is getting sufficient water.  Is this damage caused by Fire Blight, Spider Mites, or something else?  I was planning to spray it with Bayer 3 in 1 Insect, Disease, & Mite Control (which contains Imidacloprid, Tau-fuvalinate &Tebuconazole). . Any assistance would be appreciated. A. You are correct to inspector for spider mites this time of year. We usually see them when weather has been hot and dry. Spider mites can be a problem even if we don’t see webbing. Webbing isn’t always present. Spider mites love dusty leaves so washing the leaves off with water after windy weather is a good idea.   Two spotted spider mite. Actutally the size of this period…… That being said, I don’t see spider mites as a problem in the pictures you sent to me. Spider mites don’t live very long so their dead bodies leave behind kind of a dusty appearance to the leaves. I also use a hand lens and look for their tiny eggs which are round translucent balls. Finally I take a branch and slap it against a white piece of paper. I look for tiny crawly things about the size of the period at the end of the sentence.   This is spider mite webbing but doesn’t always happen I don’t think you have them. I think this problem is water related. Either the plants are watered too often, they are not given enough water when they are watered or they are given too much water. You didn’t tell me how often you water but I think you are may be watering too often. That’s my guess. Root suffocation or rot is relatively common on viburnum unfortunately. Water less often.  When you water, give them a lot Of water at one time and then hold off until they need it again. Never water these every day. At the very least you should be able to water them every other day. Maybe even every 3rd day. Increase the number and size of the emitters. The easiest way to Give them more water is to increase the number of emitters and the size of these emitters to this plant. For example, if this plant has 2 emitters Watering it, increase it to 4 emitters. If this plant has 2 gallon per hour emitters, change them to 4 gallon per hour emitters. it is better to give them too much water all at once and then wait than it is to water them every day. Improve drainage. Soils that have little amendment in them to improve the drainage get worse over time. This is because the organics in the soil decomposes and disappears. This causes the soil’s to collapse and drain poorly. This causes poor drainage and leaves water around the roots and suffocates them. Get a 1 inch diameter or larger auger that can attach to a drill. Make sure this auger is at least 18 inches long. Drill 8 to 10 of these holes within 12 inches of this plant without hitting your irrigation lines. Leave these holes open and drill more of them when they collapse or fill them with compost to help keep them open. You are creating a French drain or a sump, sometimes called vertical mulching. This helps move water away from the roots that might be suffocating them. Replace the rock mulch with wood chips. Wood chip mulch on the surface of the soil decomposes and improves the surface layer of the soil. Rock mulch doesn’t. It actually makes the soil worse for drainage.

I received this link regarding a vertical “greenhouse” constructed in Jackson, Wyoming and growing vegetables hydroponically. I thought this might interest some.The business was begun with some public economic assistance. Its goal was to replace food being transported to the Jackson Wyoming area and sold in local stores. Its aim was not to compete with local farmers. The reality is that competition is inevitable. That is the nature of our free market system. https://www.verticalharvestjackson.com/

It isn’t often I post other people’s work on my blog. Several people have contacted me they have grown bananas here in our hot and cold desert but I thought the information here should be posted for comments and discussion. Harrison sent it to me in 2015. Yes, I’m slow.  – Xtremehort A successful strategy for growing edible fruiting bananas in Las Vegas has not yet been found; it is a challenge to match our environment with the banana’s requirements. That said, it is marvelous to watch the huge purple flower emerge and slowly expose tiny green bananas, even if they are not able to mature into sizable yellow fruits. Edible bananas, Musa acuminata, are herbacious perennials that grow with a large pseudostem through which leaf stalks emerge at its tip until the growth cycle nears completion, about 2 years under favorable conditions. Then, instead of a leaf stalk growing from the pseudostem, a single flower stalk emerges, enlarges, the petals peel back from the “bud” and in between at the base of the petals are the fruits in bunches called hands. [See pictures, changes over 7 days.] After fruiting, the pseudostem dies back. Banana plants are usually not available in local nurseries so mail order is customarily required. Common cultivars are a good choice, and note that not all banana plants are edible fruiting. Search the Internet for their current availability. Order from resources that provide safe packingand shipping, and the shorter the travel time the better (the expense of air or two day shipping is sometimes worth it.) The plants will be shocked from travel in any case. Best time of year to order is spring. Fall ordering leaves short time for the plants to acclimate before winter protection must be placed. Location. Daylight and sun light are two considerations. When the days get short, say less than 12 hours, their growing slows. That is why overwintering them in a dark garage is not a good idea. They may never recover, and it can get dangerously cold there in winter. In our climate, bananas can tolerate heat but do not tolerate direct sun; broken shade is probably a best location. They should be planted in the warmest microclimate on your property. In my opinion, the growth of the plant is best if it is continuous and not interrupted by cold, wind, or heat. Banana plants tolerate wind, but not a hot, dry desiccating one, so limiting exposure to wind is also a consideration. In-ground (not in greenhouses) bananas require serious winter protection, strategies for which are available in nursery catalogues. Container planting may seem a reasonable option, especially when considering seasonable portability in anticipation of hostile weather. In warmer weather, relocating the plant should maintain its orientation to sunlight. An urn of at least 20 inches is desirable, with a radius of about 5 feet around it to allow proper leaf spread. I prefer clay to plastic or pottery. Since the duration of the plant’s life is about 36 months, accumulation of salts from hard water should not be a problem. Emerging plants in the same urn, however, should be transplanted to replacement soil. Hand watering may be necessary, and moving the watered urn is a challenge. It is a good idea to “double pot” the urn so that, in the heat of summer, roots are not “cooked.” Soil. Planting either in the ground or container, native soil is alkaline and bereft of nutrients. Various formulations have been given to improve the soil, for example, perlite, peat moss, potting soil, 33% each. The ultimate pH should be on the acid side, between 5.5 and 6.5. Well draining medium is preferred, and a generous bottom layer of cactus mix will enhance drainage. Fertilizing. A well-balanced product, either 6-6-6 or 12-12-12 should be satisfactory. I recommend applying fertilizer first when the weather warms up and once in early fall. Some recommend more frequent fertilizing and special fertilizer combinations of nutrients. Watering. For container plants, mulching and using a “water stick” is a useful guide to determine plant watering needs. In-ground plants, also mulched, are regularly watered, once per week for 15 minutes in Winter, increasing to twice per week in Spring, and perhaps once more per week at the height of Summer. Observation of the leaves, drooping when dry and discoloring when too wet, is also helpful in modifying watering schedules. Fruiting. Between 9 and 12 leaves suggest the plant is potentially able to fruit. If you count the leaves on pictures of fruiting plants in nursery catalogues you will note they almost all have at least 10 leaves. Preventing leaf loss is critical to successful fruiting. After fruiting, it will take 2-4 additional months for fruit to ripen. I have not found measuring the girth of the pseudostem helpful in predicting flowering. Pests. I have not noted any specific pests, but focused observation on plant growth should detect harmful conditions. Propagation. Bananas are easily propagated, once you are able to grow them, even if they don’t grow edible fruit. From the base of the mother plant, little plants surface, and can grow to be mature plants. These offshoots are called “pups,” and are the same cultivar as the mother plant. Following the suggestions above, I have found complete success, i.e., growing edible fruit, elusive. I have been able to get fruiting but the fruits do not grow or ripen; they are small and inedible. There are still adjustments to try, for example, timing the cultivation of “pups,” the root offshoots from the mother plant, to allow for a longer uninterrupted season may be one strategy.   For me, growing edible bananas in Las Vegas is a work in progress. Resources Francko, David A. Palms Won’t Grow Here and Other Myths. S.l.: Timber, 2011. Print. Kepler, Angela Kay, and Francis G. Rust. World of Bananas in Hawai’i: Then and Now: Traditional Pacific & Global Varieties, Cultures, Ornamentals, Health & Recipes. Haiku, HI: Pali-o-waipi’o, 2011. Print. Lessard, William O. The Complete

Has fruit been blown off your plum or pluot tree? Just too much wind for a vegetable garden? Put up a windbreak. Large-scale windbreaks affect the wind on the Windward side from 5 to 8 times its height Wind damage to purple leaf Plum This is a fact sheet on windbreaks I did years ago when I worked for the University.It was aimed more at those living on larger properties and had water to spare. Download my fact sheet on windbreaks for large areas in the desert Windbreaks do not need to be big or even use much, if any, water. All it has to do is slow down the wind to make it manageable for plants. Once this is done, you will see plums and pluots staying on the trees and not blown off. Water use will go down because there is less wind. Vegetables will be more succulent with less tearing of the leaves and they will be more soft and succulent.. Why put up a windbreak in your backyard? Fruit stay on your plum or citrus Vegetables more delectable and eye appealing Use less water More pleasurable to work in the garden or backyard A series of windbreaks can be used close to the growing area Some “do not do” facts about windbreaks in the desert Do not make them solid Do not put them on the edge of your property Do not make them out of plants Do not make them out of wood Do not put water near them Do not use plants if you need a 12 month windbreak Chain-link fence with PVC slats gives almost the perfect 80:20 spacing for slowing wind Some “do” facts about windbreaks in the desert Windbreaks should be 80% solid with 20% open space Put them close to where they are needed Use steel or cement whenever possible Construct windbreak height in a 1:5 ratio with the protected area Consider using several smaller windbreaks instead of one big windbreak Try using chain-link fence combined with PVC slats within a couple feet of the area that needs protection. The steel is very durable in the desert provided it stays dry. Diverting the wind with a solid wall causes wind turbulence in other areas. Having open spaces between solid spaces slows the wind rather than only diverting it. Reed fencing also works well for slowing the wind but needs replacement every other year. Windscreens will also work as long as they allow some wind through it to slow it down.

Q. You mentioned that citrus trees are often grafted. Are full size trees grafted like dwarf trees? Do I need to remove anything from these grafts? The only tree that really produced was a grapefruit while my orange and tangerine, produced very little over a span of 9 years. They flowered in the spring and work protected from wind and freezing temperatures. Will I have more success in getting fruit from full size trees? suckers coming from the rootstock A. All citrus bought from commercial nurseries are grafted with another tree. This grafting gives it a different set of roots. This new set of roots is called the rootstock. Most fruit trees are not intentionally grafted to rootstocks to dwarf the tree. But some dwarfing can result from rootstocks that are not terribly fast growers. If the rootstock dwarfs the tree, it should be mentioned on the label.             There are five major citrus rootstocks, each with different characteristics that benefit the tree. A citrus rootstock may be added because of soil problems, disease issues, dry soils or survival during freezing temperatures. Knowing the type of rootstock can be extremely important to commercial growers with a certain set of growing problems.             Nurseries that buy citrus to sell in the Las Vegas market usually focus on rootstocks that survive freezing temperatures. A little of this tolerance to cold temperatures is passed on to the tree itself. bud union on fruit tree making a dogleg             Look at the base of your citrus tree trunk. You will see a “dogleg” or bend (or noticeably swollen) where the two trees were grafted together at a very young age. Any shoots growing at or below this “dogleg”, called suckers, must be removed since this growth will not give you desirable fruit or benefit the tree in any way.             Remove suckers now and continue to remove them as soon as you see them. If you remove them when they are very young, they will break away easily from the tree. Don’t wait or let them get older or they will be more difficult to remove.             Older trees stop producing suckers from the rootstock if you start removing them early, when the tree is young. But if the top is killed from freezing temperatures, the rootstock will start suckering, even from older trees, and produce a vigorous new tree from or below the dogleg. It looks pretty but this “new” tree will have very poor quality fruit.              Many citrus flower and begin fruiting at the same time we have freezing temperatures. If your citrus is in a warm, protected spot you have a better chance of getting fruit. You can protect them with lights, blankets, burlap, etc. but if the temperature and wind are bad enough, protection will not guarantee fruit and a lack of damage. The tree may require temperatures of 20 – 25° F for damage to occur. However, all flowers and fruit are killed at 30 – 32° F regardless of the temperatures required for tree damage to occur.             Citrus is “iffy” in this climate. Some years you may have fruit, other years you may not. Some years they may freeze to the ground and other years sail through the winter without damage. This is the nature of our climate and growing citrus here.