xtremehorticulture – Page 18 – Xtremehorticulture

Landscapes Have Too Many Plants and they are Big!

Use Fewer Plants Using fewer plants makes the remaining plants more visually important and saves water. A landscape full of plants is enamoring. It’s a jungle of plants. The temptation in our Western Hemisphere to fill “voids,” open spaces, with plants. Western floral arrangements are full of plants. However, each plant uses water. If we cluster them together, they are easier to water, easier to manage, and collectively use less. However, the more area not covered by plants, the lower a landscapes’ water bill. Western floral design fills all the spaces with flowers. We treat our landscapes the same way. Small Plants Use smaller plants. Smaller plants do the same job as larger plants and use less water. A decrease in plant size decreases their need for water. This leads to less total landscape water demand. If you already have large trees and shrubs, prune them smaller. Making plants smaller decreases their need for water. Remember, decreasing plant numbers and size only works if the amount of water they are given is also decreased. Manage the water they get. Eastern floral design stresses using negative spaces in interesting ways. Xeric Plants Use Less Water Use xeric plants. Xeric plants are watered less often, but with the same amount of water. Plants watered less often but still look good leads to a decrease in total landscape water use during the year. To do that, these plants need to be on a separate valve or station. Place xeric plants on separate valves or “water lines” (hydrozone) from plants that need water more often. Anytime plants are watered less often, even if you give a plant the same amount of water, a landscape saves water. Palo Verde is xeric in its water use because it comes from the Sonoran Desert Water Use is Set When it is Designed Once landscapes are designed and installed, future landscape water use, and how often they need water, is carved in stone. Watering plants less often does not always lead to better looking landscapes. Some plants, like mesic plants, need water more often. Plants demand for water is not negotiable. Once a landscape design has been selected, the landscape water use is set. When plants are watered less, changes in appearance occur; growth slows, leaves or needles begin to scorch and the canopy thins, leaves or needles drop, branches die, and finally the plant or tree may die. Use this as a signal to water more often. But water deep. When water is returned, many plants spring back to life. There is a tradeoff in perceived beauty vs. water use. Landscapes do not just have to be for plants. Conserving water is a reason homeowners are encouraged to use art forms in their landscapes that do not need water. Homeowners can become familiar with creating beautiful negative spaces without the use of plants. Our job in the desert is to create landscapes that conserve water while enjoying it at the same time.

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Apricot Poor Leaf Color Could be Fertilizer or…..

Leave a Comment / fertilizer, growth, iron, leaf color, nutrients / xtremehorticulture

Q. I have an apricot tree and the leaves are a lighter green during the past couple of months. Are the leaves lacking nutrients? Apricot leaves should be dark green when it is growing and in the summer. This color is a problem or late in the fall or winter just before leaf drop. Correct yellowing apricot leaves with an iron chelate applied in the spring or compost applied to the soil surface or both. A. Perhaps. Look at this year’s growth in several places as well as its leaf color. New growth should average about 18 inches for productive trees. Leaf color should be dark green. If leaf color is a light green and new growth is well under 18 inches, then consider applying a fertilizer or rich compost. Not all new growth of apricot is red. Some stays green. This is excessive new growth on a mature apricot and should be cut back. Prune it back with a hand pruner anytime you see it. You don’t have to wait until winter or leaf drop. Look at Growth and Leaf Color Fruit tree fertilizer is applied in the early spring, usually once a year. Unless the soil is very, very, sandy, once a year application of a fruit tree fertilizer is usually often enough. Use the rate on the fertilizer bag as the maximum rate to apply. If applying twice a year, divide the rate on the bag in half. Apricots when young should get an average growth of 18 inches in a year. When it is mature maybe 8 to 12 inches of new growth each year. Apricot leaves showing inter veinal necrosis…or leaf yellowing. Defintely needs some iron chelate applied in early spring. But what about the leaf cupping? Weed killers can cause the leaves to cup. So can excessive heat in the summer. Soil Improvement Soil improvement may be needed also. Use rich compost instead of a fertilizer. Never apply a fertilizer or rich compost closer than 12 to 18 inches from the trunk. Both fertilizers and rich compost can damage plants if applied too close. To be on the safe side, water the soil immediately after the application of a fertilizer. Water “dilutes” fertilizer and rich compost. Never apply compost or fertilizer near the trunk or main stem of a plant. When applying a rich compost, rake rock or bark mulch away three feet from the trunk in all directions. Apply a thin layer (1/4 inch) of rich compost, water it in and rerake the surface mulch back into place. Do this once every year. If it is a nutrient issue from a lack of fertilizer, you will see a change in the leaf color in about two weeks. This color change will last months. Apricot tree near a lawn but the roots can choose where to grow. Growth might not be enough. Check fruit production last year, fertilizer applications and soil improvement. Inspect Irrigation Light green leaves can also be from either drought or watering daily. First correct daily irrigations during the summer. That’s a big no-no except for lawns, flower beds and areas for growing vegetables. Big trees and shrubs can’t handle that. When watering, apply water deeply to tall plants. If it calls for more continuous watering, increase the size of the irrigated area under the tree. Apply water to at least half the area under a plant. If the leaf color is light green, it may be a sign the tree is watered too often. Give the roots at least one day between irrigations during the summer otherwise the roots may “drown”. This gives the soil a chance to drain water and the roots to “breathe.”

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Growing Pineapples in the Desert

Leave a Comment / exotics, rule / xtremehorticulture

Q. I have seven robust pineapple plants; two which are very large. I plan to move them to my small greenhouse over the winter. One plant now has three pups, and a very large plant only has one pup. What would be the ideal management of the pups? Leave alone or cut down? Not a pineapple in the desert but one on our farm in the Philippines A. When we grow some pineapples for fresh eating at our farm in the Philippines, we use the tops from discarded pineapples. Commercial growers use side shoots or “pups” from known varieties. Using the tops takes a few months longer than using the “pups” or side shoots but is more economical. Pineapples are Tropical Pineapples barely survive freezing temperatures. They are tropical. Since the production time for pineapples grown in Las Vegas is closer to two years. Part of its time growing must be in a greenhouse or at least a protected area. Greenhouse grown pineapples produce fruit in less time than without a greenhouse. Heated greenhouses are like the tropics. Unheated greenhouses extend the time for planting because of the protection they provide. Use a soil thermometer for planting in unheated greenhouses. Commercial pineapples are planted 18 inches to two feet apart Even though planting without a greenhouse can be as late as mid-March you can start looking at favorable air temperatures for planting outside after mid-February. Start pineapple outside after the last possible frost and plant them in an area with very bright indirect or morning sunlight. East sides are better than west or south sides. Total time from start to finish is 16 to 24 months after planting depending on variety you choose, weather, and soil type. Mound and Warm the Soil Pineapples need warm, moist, mounded soil. Before planting them outside mound and cover a 3 x 3 area for one week with clear plastic to warm it. Plant cut tops or side shoots (pups) that have had a chance to heal for a few hours. Experienced gardeners plant tops or sides shoots from a variety they like. Space them in rows about two feet apart. They can be closer but crowding and poorly drained soil can be a problem. Water them with drip tape or tubing. Tops will produce fruit in the longest time while 4-inch-long pups or side shoots produce fruit a couple months faster. Pineapples Produce Fruit in the Desert after Nearly Two Years After about 10-15 months of growth, they should initiate flowering. If first planted in February or early March, the plant should be old enough to start flowering by the following summer. Fruiting takes about 4 to 5 months after that.

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HOA Restrictions of Wood Mulch

Leave a Comment / barrier spray, increase soil organics / xtremehorticulture

Q. I know of two HOAs that do not permit wood chips near the residences due to bark scorpions. What do you tell people? A. There are other alternatives to using woodchips in home landscapes. We need to get the organic content of our soils higher in many cases. I just thought using wood chips would be easier. Caulk Very Tiny Openings and Use a Barrier Spray Caulk openings in the foundation of your home wider than a credit card. If you choose to use pesticides, apply them to exterior walls around the foundation of the house from the ground up to 1 foot. Make applications around doors, window eaves, and other potential points of entry. This is called a “barrier spray” and applied at least once in the spring and once in the fall when temperatures begin changing. Temperature changes are the usual time bark scorpions follow their prey inside houses. Young scorpions are very susceptible to the same pesticides used for controlling spiders. Older bark scorpions are more difficult. Apply a barrier spray any time a load of wood chips is delivered and spread. They last only about one or two weeks depending on the weather.

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Non Pesticide Borer Control in Fruit Trees

Leave a Comment / natural borer control, non pesticide borer control / xtremehorticulture

Q. I did not want to use a pesticide to control borers in my fruit trees. Any other options you can think of? I have had some luck controlling borers in fruit trees using a knife. They are inspected frequently during “borer season”. A. I understand your concerns about using pesticides in fruit trees. In the desert it is more difficult when borer numbers in older neighborhoods are a problem. These beetles can be in pyracantha, cotoneasters, flowering plum, and other trees and shrubs in the rose family. Control Sun Damage Borer damage can be minimized by controlling sun damage to fruit trees, lowering the numbers of borers in a community and cutting out damage when it is seen using a clean knife. First is sun damage. Protect exposed parts of a susceptible fruit trees with shade. Shade the trunk and exposed limbs with either water diluted paint, its own growth, or anything to decrease the sun damage. Next is a high population of borers can lead to lots of borer damage. Borers are the “worms” or larvae of the adults which are beetles. Some communities, particularly older ones, have no control of borer infested trees and shrubs. This leads to an extremely high population of borers that fly about looking for places to lay eggs in these communities. Borer control with a knife When they become adults, borers exit the tree as the adult beetle. The adult beetle flies, mates, and the female lays eggs again, usually on sunburned wood of susceptible trees. No one knows exactly when these borers fly but they can be anytime from March until warm weather stops in the fall. Borer control using a sharp knife on small branches Watch for borer damage to occur. If you are paying attention, damage can be seen in early March, but its outward appearance isn’t visible to most until July and August. Then the leaves turn brown and hang from one or two dead branches. If the damage is seen early enough, dig out the living “worms” just under the bark of fruit trees using a sharp, clean knife.

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Arizona Rosewood Dying

Leave a Comment / desert native tree, disease, insect / xtremehorticulture

Q. I live in Oracle, Arizona, and my 15-year-old Arizona rosewood has some dying branches in it. Not the Arizona Rosewood mentioned in the question but it is used in Las Vegas landscapes. A. Dying branches usually indicate a water transport problem, mechanical damage, diseases, chemicals or borers. Arizona rosewood is a 12- to 20-foot-tall xeric tree native to the Sonoran deserts. It is considered a lower water use alternative to oleanders. Arizona rosewood is so new to the landscape industry (less than 30 years old) that not much is known about it. This may require some detective work on your part. It should start to flower and produce small fruit between 6 to 8 years of age so your tree should have started flowering nearly ten years ago. It is in the rose family so check for damage from borers and fireblight. Other disease possibilities that may include single branch dieback include verticillium wilt. Even though this is a xeric plant and can handle less frequent applications of water, make sure water is applied deeply and occasionally during the summer particularly during dry periods. Water applications should be about four times each year, particularly during the hot summer months, and to a depth of about 18 inches. The water should be applied to at least half the area under the trees canopy. There is some discussion about its potential sensitivity to landscape weed killers. Make sure nothing was used close to this plant.

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Pruning Lantana

Leave a Comment / summer pruning / xtremehorticulture

Q. My lantana is about to eat my house! They are 15 to over 20 feet wide each. My neighbors’ lantana are only about 4 feet across. Mine are much too large for the space given to them. Should I cut them back now? Not the lantana written about but to give you a look if you don’t know it. A. You can cut them back now to about an inch. It will leave the area bare and twiggy. There is time for them to grow and fill out again. If you have the time, selectively cut back the bigger diameter stems and leave the smaller ones closer to center. This will leave the newer flowers but reduce its size. If it does not freeze it will grow from its terminal or side buds and get big. Next year cut it all back to an inch of the soil in early January regardless of whether it freezes or not. This will contain its size. Your neighbors’ plants were probably cut back during the winter.

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Borer Prevention

Leave a Comment / borers, fruit trees, prevention / xtremehorticulture

Q. I have lots of borers in my trees. What can I do to prevent it from happening? When borers are a problem it starts about mid summer. Often it begins in parts of the tree frequented by our intense sunlight like the upper sides of limbs that are not shaded. A. First, prevent sunburn to all trees, particularly young fruit trees. Sun damage is a problem immediately after planting in our desert climate. Damage from the sun can lead to borer problems later down the road. If I were buying a fruit tree, I would buy a small tree and let it grow as a bush. This way the lower limbs will shade the trunk. Let the Tree Grow Bushy As soon as it starts to produce fruit, that next winter, I would remove the lower limbs only so the fruit does not touch the ground. Leave as many of the lower limbs as possible to shade the trunk. In fact, let it grow into a shrub. The biggest mistake homeowners make with fruit trees is to buy large fruit trees with limbs high off of the ground. If lower limbs are present, they are removed to make a tree. Buy smaller trees and let them grow to the next size. Shade the Trunk It may be the right thing to do in other climates but not the desert. Desert fruit trees need tender trunk protection from the sun to about five or six years old. If you have a fruit tree and it is “limbed up”, then protect the trunk with diluted latex paint, tree wrap or protective collar that shades it. A sign for a borer problem is limb death in the middle of summer; brown dried leaves clinging to one or more branches on the south or west side of the tree starting when it is hot. Use a borer soil drench with an approved pesticide for borers. You are not permitted to eat the fruit until 12 months have passed. This particular pesticide is best applied after flowering. Use a Pesticide as the Last Resort There are pesticides that can be used that will kill borers still in the tree. Be careful. Treat trees after they finish flowering to protect honeybees. Don’t eat fruit from that tree for one season of production after you apply a pesticide.

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Joshua Tree Survival After Transplanting

Leave a Comment / joshua tree, landscape, yucca brevifolia / xtremehorticulture

Q. We have a few Joshua trees on our property. We planted three more that were relocated from Arizona and had the proper permits. They didn’t do well so we dug them up and saw root rot. Does it make sense to cut away any damaged rot? Or perhaps you have a better suggestion all together. Joshua trees taken from the desert should be small or established in the container before planting. A. My experience with native Joshua tree survival after transplanting is that the larger the tree, the poorer the survival. The biggest reasons for lack of success were watering too often and poor soil-water drainage. Smaller plants in the desert are capable of surviving relocation better than larger well-established ones. Survival “tricks” were used sometimes when relocating plants such as orientation and soil additives. Some “tricks” made “sense” such as removal of a portion of the plants top to compensate for root loss and improve transplant success. Outside of orientation and soil additives, how are size reduction “tricks” done to Yuccas? Super Thrive is a well known additive that makes claims for improving transplant success. Some people swear by it, others swear at it. The Smaller the Plant the More Success Native plants have a very wide and established root system. Big native plants look beautiful but are exceedingly difficult to move from the wild primarily because of their established root system. The same is true of established landscape plants; smaller ones are easier to relocate than larger ones. Larger native plants like this Joshua tree has had limited success reestablishing in a landscape unless it is well rooted in the nursery. The best luck planting is with plant Joshua trees less than three feet tall that were established first. The best survival was with those under three feet in height. Dip the roots and lower stem in a Bordeaux paste and let it dry before planting. This gives cacti some protection from watering too often. Amend the soil at the time of planting and stake them if needed. Water at first planting and then every three weeks until they have rooted.

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Pruning Navel Orange Tree

Leave a Comment / citrus, Satsuma / xtremehorticulture

Q. Do you have any recommendations for pruning our poorly maintained ‘Navel’ orange tree? The main trunk has grown to about 34” from the ground and leafed and branched out. Last season a “sucker” shoot sprouted from the side of the truck and wasn’t pruned out. Now it exceeds 8’ but seems extremely happy. Get rid of that sucker from the rootstock! A. That sucker is part of the rootstock and not part of the tree. You don’t want it to stay. It should be removed when you first saw it. See how the leaves growing on it are different looking from the Mother plant? Not only that, the growth from it was so rapid the crotch makes a narrow letter “V”. It will not support the weight of itself, plus its fruit, as the tree gets bigger. Narrow crotches can support much weight. They make the letter “V” and good crotches make the letter “U”. This type of branch will split from the tree. Not only that, this unwanted growth “robs” the rest of the tree from “food” that it makes as it gets larger and denser. What wasted growth! Remove this sucker now and don’t leave a stub attached to the trunk when you do. It should have been removed when it was first seen. Remember, if growth is a size that hand pruners can remove, then do it anytime! Early Freezing Weather Makes Fruit Drop Early The most likely reason your fruit has fallen from the tree was because of early winter and spring freezes. The flowers froze, unpollinated, the fruit then died and fell off. This result can change from year to year depending on early spring freezing temperatures. Citrus in General Not a Good Choice for Freezing Climates Keep in mind this is a ‘Navel’ orange and not the best choice for our Las Vegas climate. A better choice would be a ‘Satsuma’ orange (tangerine) because of our cold winters. The tree can still lose fruit due to early spring freezing temperatures but at least you won’t lose the whole tree! However, placement in the right microclimate for either orange type, ‘Navel’ or ‘Satsuma’, may make a difference. For ‘Navel’ orange place it in the warmer microclimate of your landscape such as a south or west side. It needs protection from winter cold to survive. The more cold tolerant ‘Satsuma’ would be placed in a colder microclimate, such as the north or east side, of the landscape. This placement delays the flowering of this tree as long as possible. Your choice with which you want to keep but my vote is for changing to a Satsuma.

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