Xtremehorticulture

Xtremehorticulture of the Desert

Starting Texas Mountain Laurel from Seed

Leave a Comment / hard seed coat, legume, seed germination /

Q. I harvested some Texas Mountain Laura. Can I expect them to grow if I plant them in garden soil? Should I remove the outer shell first? Texas mountain Laurel dried seed pods A. Texas mountain Laurel can be started or propagated from seed but there is at least one major hurdle you must overcome. This hurdle is the very hard coat around the seed, not the pod. The seed is best harvested from pods that have not fully matured. If possible harvest the seed from pods that have not yet turned brown but give you a clear indication that there is a seed which has fully formed. Texas mountain Laurel For seeds to germinate they must absorb water, be at the right stage of development, have warm temperatures and air. This very hard seed coat does not permit water to enter the seed and begin the germination process.  To my knowledge, this seed does not have to be stored in cold temperatures prior to starting them from seed. Some seeds from temperate climates have to go through a simulated winter in the refrigerator before you plant them or they will not germinate.  This seed does not seem to need this. However, to be on the safe side take half of your seed and give them an 8 week cold treatment in the fridge and take the other half with no cold treatment and see what happens. Give them a cold treatment before you damage the seed coat. Damaging the seed coat without damaging the seed permits water to enter and start the germination process. If the damage to the seed coat is too deep, the seed may die.            The easiest way to damage the seed coat safely is to use a file or sandpaper and scratch or nick the seed coat deep enough so this barrier is breached but not deep enough to damage the seed itself.            There will be some variation in these plants because they are propagated sexually, that is by seed. When these seedlings first come out and reach about 1 foot in height you can begin to discard plants that don’t have the size or shape that you desire. This is called “roguing” out the seedlings. Here is a good website to look at. http://uts.cc.utexas.edu/~harms/MtL-seed.html This website seems to say it needs a cold treatment http://homeguides.sfgate.com/grow-mountain-laurels-seed-25353.html

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When to Plant Tomatoes, Peppers and Eggplant?

Leave a Comment / Uncategorized /

Traditionally, by the middle of March at around the 2000 foot elevation in southern Nevada, we will have a 90% chance that there will be no more frost. This is normally the date we use for planting warm season vegetables. Strong and vigorous tomato transplant You can usually sneak them in a little earlier if you watch the weather forecasts or give them some protection. Tomatoes are warm season crops and they can suffer from chilling injury. This is damage to the plants if temperatures drop close to the same temperature in your refrigerator. Even a bit higher than this. Hot microclimates in the yard can support please vegetables earlier than the middle of March. So if they are going in a spot that is West or South facing, you can put them in earlier. Watch for temperatures below 50° F. If temperatures are going to drop this low, there is a potential for chilling injury. You can use some hot caps and cover them at night when the sun goes down. White woven crop cover rolled back showing the differencein plant growth a crop cover can make in spring You can use a crop cover and lay it over the top of them. These crop covers will give you an extra 5° F over the lowest temperature during the night. You can throw a light blanket over them if you push in some short stakes to keep the blanket from crushing plants. Or you can buy the plants and leave them in their containers. Put them outside during the day and move them indoors at night. This way you can delay planting them if you think there might be some low temperatures coming.

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Strawberry Tree Needs Extra Care in the Desert

Leave a Comment / leaf drop in strawberry tree, Strawberry tree leaves Brown, Why are my leaves turning Brown /

Q. I have a strawberry tree that is probably getting too much sun. The tips of the leaves are very discolored. Is there anything I can do to help it? A. Strawberry tree is native to Western Europe and the Mediterranean region.  Its leaves tend to yellow because of micronutrient fertilizer problems, cold temperatures and intense sunlight. Leaves also tend to scorch on the tips in very hot locations with intense sunlight. They do not perform well in rock mulch in south or western exposures. Getting this plant closer to optimum health helps it tolerate stresses caused by extreme soil and environmental conditions. Soil improvement and wood surface mulch will help this plant a lot. This plant should not be in rock mulch. Rock mulches radiate a lot of heat during the summer and add nothing back to the soil. If this plant is in rock mulch, I would pull the rock back a couple of feet and apply an inch or two of compost. After lightly incorporating the compost into the upper soil surface, I would cover the exposed area with about 3 to 4 inches of wood chips. The combination of compost and decomposing wood chips will help to rebuild the soil around the roots. Rebuilding the soil around the roots improves the biological activity of the soil and overall plant health. From your picture, the foliage otherwise looks healthy except for its scorched leaf tips. I would guess it is getting adequate amounts of fertilizer. Applying fertilizers regularly to desert soils is frequently not enough to provide a plant with optimum health. Be sure to add an iron chelate such as EDDHA in a spring application of fertilizer once a year. The combination of the right kind of fertilizer, soil improvement and wood surface mulch will bring this plant closer to optimum health and better tolerance for hot locations.

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When Should I Prune My Vitex Tree?

Leave a Comment / chaste tree, flowering in vitex, how to prune vitex, monks pepper, when does vitex produce flowers /

Q. When should Vitex tree be trimmed and how much should be cut? Vitex in its winter form A. Vitex blooms in early summer through late June or July. If this plant is pruned with a hedge shears you will likely affect how it blooms this summer. Larger vitex in late June Vitex with flowers in June Any pruning done now should selectively remove entire branches back to a crotch. This is a pruning technique called “drop-crotching”. This technique reduces the size of a plant while still retaining its natural form. Drop-crotching avoids plant injuries due to “topping”. Vitex in bloom in May Limbs that add height or size are removed at the juncture with a branch of smaller size. This type of limb removal maintains terminal buds at a lower height, retains flowers and maintains the architecture of the plant. The opposite of drop-crotching is topping, or shearing the plant at a desired height or size. We do not want to do that to most trees. After reducing the size of Vitex we would remove any crossed branches or broken branches and shape the tree to maintain its symmetry.

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Can I Save My Wind Damaged Tree?

Leave a Comment / how to repair wind damage to large trees, repairing split crotch /

A. yes, both branches can be saved or you can remove one of the larger branches but I know removing a large part of the canopy will make it look ugly. Repairing this type of damage is best left for professional arborists.  If you want to tackle this yourself or hire someone to do it under your supervision, then this would be the procedure you would follow. Pay particular attention in getting the right supplies for this type of job.  Any permanent steel that enters and stays inside the tree should be stainless. Any steel outside of the tree that would be resistant to the environment would either be stainless or galvanized. But it is very important to use stainless on anything in contact with wet tissue inside the tree. It is also important to make sure that the supplies you use are strong enough. Use American or Western manufactured steel products. Avoid Chinese made steel products. I have been very disappointed in the quality of some of these materials from outside the United States. I realize why they are available but these supplies have to be able to accommodate the bearing load of that tree in future years. This type of repair to a very large tree is usually beyond the abilities of most homeowners. There is also the possibility of future liability if this work is not done correctly. Having said all that, these are the basic steps that should be taken. Supplies you will need: stainless steel eye screws with a length long enough to penetrate 1/3 the diameter of the limbs galvanized, stranded wire cable with a working load limit capable of supporting the canopy (for large canopies cabling may need to be done in multiple locations) stainless steel partially threaded rod, washers and nuts Equipment you will need: chainsaw or arborists handsaw large enough for drop-crotching limbs power drill or manually operated brace wood bit long enough to drill a continuous hole through the split to accommodate the partially threaded rod 1. Reduce the load (weight) on both sides of the split by removing some of the top growth. Use a technique called drop-crotchng to remove top growth. Drop-crotching is selective removal of branches. The removal of these branches is at the “V” where the tallest branches come together with a side branch. Removal of these limbs should be just outside the “collar” of the limb to promote faster healing. Sanitize and disinfect all blades or bits used for entering the tree prior to its use. 2. Drill pilot holes for the eye screws into major limbs for securing the stranded cable. Secure eye screws into the major limbs a distance into the tree of one third the diameter of those limbs. Eye screws should be stainless steel, not galvanized or zinc plated. Large canopies may need two or more locations where eye screws are inserted and cabling is secured. 3. Secure stranded galvanized cable through eye screws and use a block and tackle, come-a-long or winch to pull these major limbs together enough so that the split visually disappears. Treat the top of the split with grafting wax to keep water from penetrating to the inside of the tree. The grafting wax is not permanent but helps keep water out of the crack until compartmentalization of the damaged area can occur. You can also use water-based asphalt sealer. 4. Drill a continuous hole through the trunk at the split. The hole should be continuous to accommodate a steel rod large enough in diameter to assist in bearing the load of the canopy. 5. Insert the stainless steel rod and secure both ends with stainless steel washers and nuts. Tighten the nuts to assist in bearing the load of the canopy. The tree will eventually engulf the steel rod, washers and nuts. You should remember to notify anyone who might remove the tree that there is a steel rod in the interior at the split. You can read more information on this and see some pictures of how this is done at: http://essmextension.tamu.edu/treecarekit/index.php/after-the-storm/tree-damage-and-hazard-assessment/repairing-storm-damaged-trees/ http://www.kbs.msu.edu/information-resources/repairing-storm-damaged-trees http://gearycountyextension.com/Hort/Stormdamagetotrees.pdf

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Black Spot and Rust Not Common in Vegas Roses

Leave a Comment / Black spot of rose, diseases of roses, rust of rose /

Q. Here’s the pic of what’s going on with my roses.  What do you think?  Black spot or rust? A.This was sent to me in July, 2014. I really didn’t see any black spot or rust in the picture. Black spot of roses have the typical “black spots” on the leaves and rust are pustules on the leaves that can be rubbed off with your fingers. Both are more common during the spring, periods of high humidity and too much shade. Usually full sunlight, drip irrigation (no overhead irrigations), watering during early morning hours, fertilizing regularly and our dry conditions seldom lend itself to either disease here. If you need to put on a preventive treatment on roses in the spring or fall, apply one of these treatments to the leaves: sulfur dust, Neem oil or compost tea. The damage looks more like spider mites, drought or lack of fertilizer. Make sure roses have an organic surface mulch applied to the top of the soil that decomposes (wood chips), use drip irrigation, water early in the morning and are fertilize during the spring and fall months. 

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How to Correct a Bad Haircut on Rosemary

Leave a Comment / How to prune rosemary, shaping rosemary /

Q. I have a rosemary bush in the front yard that’s very healthy but has grown quite big in the seven years since it was planted. Is there a technique to trimming? I tried once before and it looked like a really bad haircut. A. Rosemary can be quite dense in its interior if it is watered and fertilized normally. It becomes denser if it is pruned with a hedge shears. If rosemary is very dense, very little light penetrates inside the canopy. This lack of interior light causes leaf drop resulting in an interior that is only wood. Pruning with a hedge shears results in a surface layer of green foliage only an inch or two deep. This surface layer of green foliage is new growth which has been sheared. If left draped over a wall, the new growth may be several inches long. Dramatic pruning of an older plant can result in that “bad haircut” you mention that reveals its woody interior. The only portion that can be removed safely without causing a “bad haircut” is a small portion of the green surface layer. Rosemary will regrow once it has a bad haircut but it takes time and you and others are forced to look at the bad haircut until it grows back during warm weather. Any extensive pruning of rosemary that can result in a bad haircut should be delayed until warm weather. You have two options. The first is to go ahead and give it a bad haircut beginning in about April knowing full well will take time to recover. The second is to remove older plants and replace them with younger plants that you can begin to shape at an early age. Once pruning has been initiated with a hedge shears, the shape of the plant is difficult to correct. If you wanted to be an ornamental rosemary is one of the easiest plants to prune. It adheres to any shape you want to give it. At Christmas time rosemary is available in nurseries in many stores shaped into 3 to 4 foot tall Christmas trees. I’ve seen it planted around trees and the shrub is carved out around the trunk. I’ve seen it planted in a raised planter and cut off along the wall like bangs of the haircut. I prefer a more normal look which used to reach deep inside the plant and remove older wood. Every time you make a cut, it is hidden by the growth that’s remaining. If you prune like this, it will never look like you even touched it except it smaller. Look for the growth that is longest, follow the stem back inside the canopy of the plant to a place where there is side growth or side branch. Cut just above this side branch so the side branch can continue to grow but you are removing the longer stem. Usually you would do this in three or four locations. Depending on how restrained you want the rosemary to be, you might do it annually or every 2 to 3 years. Prostrate rosemary in natural form in rock landscape

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Companion Planting Successes Can Be Variable

Leave a Comment / companion planting, Companion plants, companion plants for vegetable gardens, what vegetables are friends to other vegetables /

Q. I am looking for a spring companion list for Las Vegas. I have an easy to read chart for fall in order to know where to put different plants and which ones don’t like to be next to each other but can’t find the same resource for spring. A. The topic of companion planting is very large and has a lot of good information but unfortunately it also has a lot of folklore that is either regional in nature or lacks validation. Companion planting can focus on the inter-planting of crops, the use of understory crops, the planting of trap crops, suppression of pests by other plants, planting to increase the levels of predators, and more. For the general public, the term has evolved into the planting of crops for mutual benefit. These companion plants are sometimes referred to as “friends” to other crops without getting into much detail. There is good evidence for the planting of trap crops for aphids, whiteflies, nematodes and a few other pests. I have heard anecdotal evidence for the use of plants like garlic for repelling certain types of insects or even rabbits. Some people will swear by it and other people who have tried it may say it doesn’t work. This opens another set of problems because in some cases it may work and in other cases it may not which causes confusion. I have tried to maintain neutrality on these issues and recommend situations where I am comfortable there is solid scientific research to support it or not support it. People are free to post their suggestions on my blog and I will publish them provided they are commercial neutral. Where I am comfortable recommending companion plants are in the areas of trap cropping, inter-cropping and the planting of understory plants. There are some very good evidence that interplanting of crops can have some big benefits including a reduction of pest problems compared to large-scale monoculture where only one crop is grown. Without getting into detail, there are areas I am very uncomfortable making recommendations because there is contradictory information or the research flatly does not support it. For people like yourself who want to experiment in these areas, I strongly support it and test it for yourself. No one can dispute it if it works for you. There are publications that do support this kind of gardening activity such as http://www.gb0063551.pwp.blueyonder.co.uk/seeog/companion/ http://www.gardeningbirmingham.co.uk/herb-companion-planting/ http://www.ghorganics.com/page2.html Other sources you may be familiar with include MotherEarth News, Old Farmer’s Almanac, and many others.They are fun to read! A balanced assessment of companion planting was done by Cornell and can be found at http://www.gardening.cornell.edu/factsheets/ecogardening/complant.html 

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How to Prune Arizona Rosewood Against a Wall

Leave a Comment / desert landscaping, How to prune desert trees /

Q. I planted a 5 gallon Arizona Rosewood a year ago against a wall for visual screening. How and when should I prune it? Arizona Rosewood one year after planting A. This plant can be grown as a shrub or small tree. As a shrub, led it continue to grow as it is except for any weak stems. Any weak, floppy stems should be cut back about 1/3 to half their length to encourage them to become stronger. As a tree, it can be grown with a single trunk or multiple trunks. This initial pruning to establish its architecture or form should be done during the winter or early spring. It is not too late now. If your plan is to use this as a small tree, then I would select 3 or 5 larger diameter stems (an odd number is more pleasing to the eye) coming from the ground and eliminate all other growth coming from the base. As new growth appears from the base, eliminate it at any time of the year you see it. Next, stake these stems individually in an arrangement you would like them to grow. Staking young stems for one year will encourage them to continue growing in those directions. Finally, cut any long, floppy stems back to encourage strength. Make these cuts ¼ inch above a side branch in any direction away from the wall. Remove any strong growth growing towards the wall. Here is some excellent information with more background on Arizona Rosewood by an extension agent in Arizona. http://ag.arizona.edu/yavapai/anr/hort/byg/archive/arizonarosewood.html

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Why Are My Leaves Yellowing on Loquat?

8 Comments / leaf drop, leaf yellowing, why are my leaves turning yellow, why are the leaves falling /

Q. The leaves closest to the trunk of my two-year-old loquat have started turning yellow and falling off. New leaves have started to grow and they look fine. It was a 5 gal tree when I planted it. Last year the tree grew very well and produced a few loquats.This year the amount of fruit appears to have doubled but it has developed this leaf problem.  I did some research on loquat leaves turning yellow. They suggested overwatering might be the problem.  I give it about 24 gals of water once a week. I checked the soil with a moisture meter and it does not show being wet. A. I cannot give you any definite answers why your loquat has initiated leaf drop and yellowing of the leaves. I can tell you this; many leaves will yellow just before they drop from the tree so this type of yellowing just means that the leaves have died and will drop soon. The leaf color of loquat without chlorophyll is yellow. When the tree has initiated the dropping of its leaves, the leaves will lose their chlorophyll and hence their green color. The remaining color after the chlorophyll has disappeared will be yellow due to the presence of carotenoid pigments which are masked by the presence of green chlorophyll. Most likely this tree went through some sort of shock. This shock initiated leaf drop. The shock can be related to water, salts including salts from fertilizers, a light freeze, toxic chemicals or salts such as a high concentration of fertilizer applied to the leaves, etc. The water-related problem can be from too much or not enough. For instance, if it went through a very dry spell it will drop its leaves. If the soil is too wet for an extended period, it will drop its leaves. If fertilizer was applied to close to the trunk or the rate was too high for the plant, it will drop its leaves. There are two types of overwatering; one is related to the volume of water the plant is given while the other one relates to how frequently the water is applied. The overwatering I am talking about is applying water too often, not overwatering due to applying too much water in a single application. Once a week is not too often in my opinion unless you have a drainage problem. If you do not think the soil has been too wet or you have not fertilized the tree by either applying fertilizer to the soil or spraying leaves, then I would just wait and see what happens. If you applied fertilizer to the soil and you suspect the application was too strong, then flood the area with water and push the salts through the soils and away from the trunk and past the roots. That’s probably the best I can do without more information.

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