Xtremehorticulture

Xtremehorticulture of the Desert

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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Should We Keep Politics Out Of Gardening?

1 Comment / how can you reduce the temperature on a cinderblock wall, reducing the heat from block walls, Tomatoes and heat /

I’m not so much asking a question as telling one of my solutions. My garden is along an East facing concrete block wall and though shaded in the afternoon there is still considerable heat coming off it during the summer.   Add caption Two years ago I stopped someone picking up election signs and asked if I could have some.  They said yes and I got enough to do most of my garden.  Through procrastination and adult life I didn’t manage to get them onto the wall until late June.  My tomatoes were growing OK but they were leaning away from the wall and you could really feel the heat when close to the wall.  I mounted the signs on the wall to kinda insulate it from the sun in the hopes of reducing that reflected heat.  It worked really well as within two weeks the difference was noticeable.  The plants had started growing more upright and appeared to take on a new life.  This year I got some more and expanded the coverage to the entire garden.  Took less than two hours and I’m hoping it helps to grow a bumper crop of tomatoes. Pictures attached hopefully.  You can use all of this if desired but please, no name or e-mail address.  Thanks. Now if I could just figure out what’s wrong with my peach tree I’d be set.

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Prune Grapes to Improve Production

3 Comments / How to prune grapes, how to prune table grapes, how to prune wine grapes /

Our climate in the Mojave desert can damage grapes during the cold winter months. This winter was warmer than usual and the two times it dropped into freezing weather this winter was when plants were deeply in their winter slumber. That’s good. Freezing weather occurring early in the fall or late spring is typically more damaging than the same freezing weather in midwinter. For small-scale producers and backyard gardeners I like to tell them to prune their grapes last. Wait until the most brutal part of the winter is over and then prune. The reason for this is simple. When we prune grapes we typically remove everything on the plant that is not necessary. When we are finished pruning we leave behind very short Spurs or longer canes depending on the variety of grape. Regardless, for good production we need everything that we have left after pruning to be alive. Temperatures in the Mojave desert can drop to temperatures that can damage grapes. If we prune grapes too early and this is followed by very cold temperatures, we can lose some and possibly most of our production because of the death of these spurs or canes due to cold. Here are some tips on pruning table and wine grapes: 1. When you prune grapes and the temperatures are warm, grapes will bleed. That is, you will see water coming from the cuts. This is normal. This is water being pumped up the vine by its roots in preparation for spring growth. They may continue to weep like this until growth starts and the leaves suck this water away from the cuts and the cuts have a chance to heal. 2. Identify all of the growth that occurred last year. This will be a different color than the older growth or it just will not look as old. Once you have identified last year’s growth, you can cut all of them back so that the new growth is about 18 to 24 inches long. These long canes are where your grapes are going to be produced. 3. Space these long canes which will produce grapes about 12 inches apart. You want to do this for table grapes because this will encourage the berries to become larger. You want to do this two wine grapes because you want to concentrate the flavors developed by the plant into fewer berries. Choose healthy and vigorous canes to be your producing canes. Identify any canes that are between your producing canes. You can either remove these or them back and remove all of last year’s growth. If you remove a cane, you will remove the fruit. Grape pruning progression for spur pruned grapes. Cane pruned grapes are justlonger spurs. 4. The remaining canes will be cut back to about an inch long (spur pruned) or about 12 inches long (cane pruned). If you want to get technical, identify the buds on the canes. When spur pruning, leave only one to two buds remaining. When cane pruning there should be 10 to 12 buds remaining. 5. If you have Thompson seedless grapes, or Black Monnuka do not spur prune them. These should be cane pruned. Make sure you have 8 to 10 buds present on the cane when you’re finished cutting.Most other table grapes are spur pruned. Most wine grapes for our climate are also spur pruned. Here are some previous posts on my blog concerning pruning grapes. http://xtremehorticulture.blogspot.com/2012/12/how-to-prune-table-grapes.html http://xtremehorticulture.blogspot.com/2013/03/spur-or-cane-prune-my-grapes.html http://xtremehorticulture.blogspot.com/2011/10/maxwell-norton-gives-table-grape.html

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How to Control Whiteflies on Tomato This Summer

Leave a Comment / Controlling white flies, how to control whiteflies /

Whiteflies on the bottom of pomegranate leaf Q. I am new to gardening in the desert and am surprised at my success thus far!  That is, until the white flies came.  They showed up on the grapes and zucchini first, maybe in May or June.  Unfortunately, I didn’t think they would become a problem. By August they had attacked everything! I pulled broccoli plants and found I needed a mask to keep from inhaling them! What can I do this season? A. Whiteflies are a very tough to control once they get established in the numbers you are talking about. They are much easier to control if you’re diligent about controlling them when you first see them. Females lay a couple hundred eggs at a time and these become adults that can lay more eggs in about six weeks. This means you can have exponential growth in their numbers if they are left undisturbed in six weeks. Whiteflies, like so many garden pests, do not show themselves but remain hidden. Unless you stoop over and turn over leaves and look at their undersides, you will not know they are there until you see their telltale signs of plant damage. Signs of damage are yellowing and scorching of older leaves, sticky residue on upper leaf surfaces of lower leaves and ants. Bottom leaves of sunflower yellowing and scorching due to past problems on the bottom side of the leaves. Photo courtesy Viragrow. Ants love the sticky residue that whiteflies and aphids produce. Ants climbing on plants in the garden or on fruit trees is a very good sign you have a developing pest problem. Backpack sprayer suitable for vegetable and Orchard spraying If you buy transplants to put the garden, spray the undersides of the leaves and the stems with insecticidal soap, neem horticultural oil. Once the transplants have been placed in the garden and they have grown a little bit, remove the bottom leaves of transplants that are within a couple inches of the soil. These bottom leaves are perfect hiding and living quarters for many of the problem insects. They are so close to the soil surface they can’t be sprayed effectively. Stay away from conventional garden insecticides unless this past really gets out of control. Whiteflies are resistant to many conventional pesticides and these traditional pesticides can knock out whitefly predators that help keep them under control. Get yourself a decent compressed air garden sprayer such as Solo or Chapin and use soap and oil sprays in rotation with each other. Early in the season when it is still cool, check the undersides of the leaves and look for critters. Weekly applications are probably enough during cool weather. When it starts to get warm, inspect the bottom sides of the leaves and spray twice a week. Make sure you spray the undersides of the leaves. That’s where these critters are! Control ants that are getting into the garden. They are buddy buddy with aphids and whiteflies. Ants come from a nest in the ground. Follow their entourage back to the hole in the ground and treat around the hole with a bait that they can carry back to the nest. These are the most effective for ant control. If you see bottom leaves that are starting to get yellow, pinch or clip them off. If they started to turn yellow they are contributing to the plant anymore. Look at the underside. There are probably critters feeding away. Removing these leaves, removes pest problems.

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Fertilize More Often For High-Quality Roses

Leave a Comment / how often should I fertilize roses, what is the best fertilizer for roses, When should I fertilize roses /

Q. I’d like to continue fertilizing my rose bushes right through the spring since the past year’s bloom was not too impressive. Is there any advantage or harm with that strategy? A. High quality roses are typically fertilized about every 6 to 8 weeks through the winter, spring and early summer in our climate. Fertilizer applications are usually stopped during the summer months when flowering is the worst and resumes about a week before good flowering resumes. SulPoMag conttains magnesium and canbe substituted for epsom salts Fertilizer applications are made to support healthy, vigorous growth and flower production. The timing of these applications varies with the type of rose and variety as well as the microclimate. Generally speaking, roses perform very well in our climate for about 8 to 9 months of the year. Microclimates that are warm and protected in the winter may support the flowering of roses through the entire winter. In these microclimates you would fertilize all winter long. In cooler microclimates you may see an interruption in flowering during the winter but have a longer flowering period in spring and fall. Fertilizer applications would support roses during their flowering periods. If you are fertilizing roses more often, then use smaller amounts of fertilizer or use fertilizers that release nitrogen more slowly. Make sure that your roses receive an annual application of iron that is applied just prior to new growth. Many rosarians like to apply Epsom salts as part of their fertilizer regime for the magnesium contained in it. Other fertilizers like SulPoMag and some palm fertilizers also contain magnesium and may be an appropriate substitute.

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Crazy Roots of Tomato Is Due to Nematodes

3 Comments / bumps on tomato roots, how to discourage nematodes, Root knot nematode, what will grow with nematodes /

Q. I was going through my garden notes and I found pictures I took a few months ago of my tomato plants.  A few of them came up with real gnarly roots, I have never seen anything like it.   A. This is definitely root knot nematode judging from your photos. There really is no way to totally rid the soil of nematodes. In the past, soil fumigants were used on a regular basis to knock these critters back. Soil fumigants are being eliminated from the pest control arsenal due to environmental concerns. Your options are to move your growing area to a new location that is not infested, grow in raised beds or containers and use resistant varieties. There are some vegetable varieties more resistant to nematodes than others. Roots of tomato plant from reader Use varieties that have a capital “N” after their name. This stands for “nematode resistant”. An example would be the tomato, Better Boy VFN which is resistant to Verticillium and Fusarium diseases as well as nematodes. Build up your organic matter content with lots of compost. Nematodes don’t like soils with high organic matter. Be very careful of transferring soils contaminated with nematodes to new beds or containers. This includes using contaminated gardening utensils. Make sure utensils are sanitized between locations. It is possible for this pest to migrate from your existing soil to a new raised bed constructed on top of contaminated soil. You might to consider laying thick plastic underneath the raised bed. Make sure the plastic is sloping slightly for drainage and make the bed at least 12 inches deep. Here are some links back to my blog where I have written about nematode in the past. http://xtremehorticulture.blogspot.com/2013/03/use-plants-resistant-to-nematodes.html http://xtremehorticulture.blogspot.com/2013/12/nematodes-permanent-garden-problem.html http://xtremehorticulture.blogspot.com/2011/07/twisted-and-distorted-tomato-roots-may.html http://www.reviewjournal.com/columns-blogs/bob-morris/nematodes-are-manageable-never-go-away

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