Xtremehorticulture

Xtremehorticulture of the Desert

Growing Fruit Trees in Containers and Transplanting Into the Ground

1 Comment / apricot, citrus, container, container trees, pluot, pomegranate /

Q. I would like to plant some trees in containers until I can plant them in my yard in a few years. Can they stay in containers if I’m careful with them?  I’m thinking about apricot, pluot, orange and maybe a pomegranate. A. If you have purchased these in containers you will probably not want to keep them in the same container more than perhaps that single growing season if you plan to plant them in the yard. Generally speaking, if you plan to replant them then they should be moved into progressively larger containers or the roots will be permanently damaged. Eventually, the containers you’ll need will have to be large, whiskey barrel-sized or larger. 15 year old Gold Kist apricot at the orchard with minor pruning for size control             Once these trees start to get bigger they will transplant into the yard with more and more difficulty. This just means they are more likely to suffer from transplant shock and recover from this shock more slowly when moved. I would recommend that if you want fruit trees in containers then keep them in the container permanently. When you are ready to plant in the yard then purchase trees specifically for the yard.              Of the group you mention, citrus is probably the best choice for a container. Try to locate a citrus on a dwarfing type of trifoliate orange rootstock. Trifoliate orange rootstock is very cold tolerant which you will need in our climate unless you can protect the plant from freezing temperatures. There are a few selections of trifoliate orange rootstock that are more dwarfing than others. Focus on these if you can find them.             My next choice for a container might be one of the smaller pomegranates like the variety ‘Sweet’ which would be a better choice for containers as opposed to ‘Wonderful’. The fruit is excellent, as good as or better than ‘Wonderful’. Read about Sweet pomegranate at Dave Wilson Nursery             If you select an apricot then I would pick one of the miniatures like ‘Pixie-Cot’ or a standard sized tree like ‘Gold Kist’ which tends to stay smaller when on Nemaguard rootstock at least. Read about Pixie cot and Gold Kist at Dave Wilson Nursery             Among the pluots for a container I would probably pick ‘Flavor King’ which stays naturally smaller than some of the other pluots but it will need a pollenizer tree such as ‘Santa Rosa’ plum. Read about Flavor King pluot at Dave Wilson Nursery             Don’t expect these trees to be long-lived if you keep them in containers. I hope this helps.

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One of Several Pine Trees Sparse and Scrawny

Leave a Comment / brown needles, circling roots, disease, drought /

Q. Why does my one pine tree seem so sparse and inadequate?  I purchased four Mondale pines and treat them all equally. But one of them looks so scrawny.  The other one shown looks healthy and appears to be robust.  Any thoughts on that?  A. The usual reason for a pine tree being sparse and not full is that it is not receiving the same treatment as the others. Pine trees generally maintain needles on their branches until the wood gets to be three to five years old and then the needles are dropped from the older wood. This older branch is needle-less except for small branches growing from it less than five years old.             The reason for canopy thinning is the loss of needles at a higher rate than they are being replaced. So bottom line for a pine tree becoming sparse is that the tree is not putting on enough new growth. Reasons for this include a lack of water, fertilizer, damage to the tree, or less likely, diseases or insects. Pine needle brown dieback due to lack of water             By far the most common reason is that the amount of applied water is not enough. So when you say you treat them the same it does not necessarily mean these treatments are all reaching the trees equally. But if there is inadequate water two things will happen; the tree will put on less growth and the needles will begin dying back from the tips.             The first thing to do is to check and make sure that whatever is delivering water to the tree is not plugged. Secondly, make sure that water is not running off the surface to some other location. Just because water is applied to a tree does not mean it is getting to the roots. Circling roots of semi mature tree due to circling roots in the containers             Remember, that as trees get bigger their demand for water increases. The increase is not simply a few gallons per year but is much greater because trees are three dimensional in their water use unlike a lawn. Unlike a lawn, when a tree doubles in size its need for water more than doubles.             The next most common reason is that the roots of the tree never fully established into the surrounding soil after planting. This can be because the tree was too old for the container and the roots started circling and never established into the landscape successfully.             It can also be because the tree was not firmly staked at the time of planting. Correctly staking a tree will immobilize the roots and help them to establish successfully into the surrounding soil. You should be able to push on the trunk and NOT see any movement of soil at the base of the trunk.               The next most common reason is damage to the roots or trunk. This will be far less likely than a watering problem but much easier to identify. This can be physical damage like construction, damage from chemicals like salts or weed killers, insect or diseases like collar rot.             If the tree is being shaded by other plants and not receiving enough light (at least six hours a day) then these branches in the shade can drop their needles. If this is the case then some pruning to allow more light will help. If they are planted too close together then consider removing trees so the remaining trees will thrive.

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Pyracantha Has No Berries

Leave a Comment / firethorn /

Q. Would you happen to know why my eight pyracantha bushes did not produce red berries this year?  I did not see birds helping themselves. A. On your pyracantha the only thing I can come up with is either that they did not flower (you did not tell me if they flowered or not) or that a late freeze eliminated the fruit crop. We did have a late freeze in the spring which eliminated many plums and apricots this past growing season.          Another possibility could be how they were pruned. If they were pruned in such a way that the flowering wood was removed, then it is possible the fruit would be removed as well. If your pyracantha bloomed this past year and did not fruit then this means it was most likely a late frost. I hope this helps.

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Small Dark Green Circles on Lawn

Leave a Comment / dog damage, dog urine, green circles, lawn, turfgrass /

Q. I have nice green circles on my lawn. Yes, I have three dogs!  The lawn was put in about nine months ago as sod.  It suffered from minor fungus last summer and those areas were resodded about three months ago which you can see in my photo.  About a week ago I added a nitrogen only fertilizer.  Do I need to add something else to the lawn?  I would like the lawn to look green like the circles which I assume are a result of my dogs!  Or is this some other issue? A. Thanks for telling me you have the dogs. You must read my column. Green spots or small circles can be from dogs. If it is from dogs, the spots are usually 6 to 10 inches in diameter with a smaller circle of dead grass in the center. Dog urine damage to lawn. If the lawn had been fertilized with a high nitrogen fertilizer at Thanksgiving the circles would not be as notieable             The concentrated dog urine kills the grass in the center of the green spot due to its concentration but acts like a high nitrogen fertilizer as it becomes more dilute further from the dead grass. The diluted dog urine causes the grass to become greener and grow more rapidly. So the dark green grass surrounding the brown dead center is frequently taller than the surrounding grass.             If it is warm outside, an application of high nitrogen fertilizer plus one or two mowings to remove the brown dead tips of grass should even the color out through your lawn. Nitrogen is the primary fertilizer responsible for having a green lawn. The other is iron. You cannot substitute one for the other. Nitrogen also stimulates growth. Adding more nitrogen means mowing more often.             Your lawn is very dense in the picture. This might also contribute to disease problems. You might try reducing your fertilizer applications to about half of what you are applying now to decrease its density and help improve air movement through the grass. This might help reducing disease potential when it is hot outside.             You could also try mowing your lawn a bit shorter in the summer months, no shorter than 1 1/2 inches. This might also help reduce disease potential. Make sure you are irrigating your lawn in the early morning hours, not at night where the water can sit on the lawn for several hours before it evaporates.             I have a class coming up on lawn care management on Sunday, February 26 at noon at Plant World Nursery.

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Controlling Bermudagrass in a Fescue Lawn

Leave a Comment / bermudagrass, devil grass, eliminate, invasion, kill /

Q. I spoke to you about my patch of Bermudagrass at one of your classes. You said that Bermudagrass could be controlled just by letting a fescue lawn shade the soil. Can I really get my Bermudagrass under control simply by mowing higher? Winter fescue lawn with dormant bermudagrass now obvious. Invasion of bermudagrass is because sprinklers cannot irrigate a triangular patch of grass efficiently. Under irrigation = bermudagrass in the hot desert. A. No, you cannot control existing Bermudagrass in a lawn just by letting the fescue grow taller. I think I was misunderstood. Once you have a fescue lawn established, by keeping the soil shaded you will reduce and possibly eliminate Bermudagrass from getting started. This is what I intended to be heard.             Bermudagrass cannot survive in shade. By keeping the soil surface shaded by a healthy lawn, Bermudagrass will be discouraged. Bermudagrass invades a home lawn where lawns are mowed too short or damaged, thus eliminating shade on the soil surface. Typical places where it invades include around sprinkler heads and the edges of the lawn near concrete. Both of these places are where line trimmers are frequently used to keep grass shorter.             It also invades damaged areas due to under irrigation, disease or insects. Once established in the lawn, Bermudagrass is nearly impossible to eliminate without renovating the entire lawn. This would mean fertilizing, watering and mowing the lawn to get it as healthy as possible and then killing it with Roundup.             This is best done in the fall around mid-September to mid-October. About 10 days after the Roundup application or applications, the lawn can be mowed extremely short, power raked until you see bare soil and reseeded directly into the dying or dead lawn.             The key to eliminating the Bermudagrass will be getting a thorough kill with the Roundup before replanting. Spray once, mow in two days and spray again going 90 degrees to the first spray to get good coverage and a better kill.

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Ferilizing Photinia, Iris, Hollies and Italian Cypress

3 Comments / shrub fertilizer /

Q. I want to know when and how to fertilize most of my shrubs.  I have a lot of Photinia, iris, Japanese hollies and Italian cypresses. Iron chlorosis on photinia in rock mulch A. Flowering plants should be fertilized a few weeks just prior to flowering and the development of new growth. If flowering and new growth coincide with each other, then one application of fertilizer just prior to that combined event is all that is necessary.             If new growth starts and then flowering occurs later, then you should probably fertilize a second or even third time during, or slightly after, flowering. Usually if we grow plants specifically for their flowers (roses are a good example) then regular applications of fertilizer through their flowering season might be considered. A slow release fertilizer could be substituted for multiple fertilizer applications.             Once they stop growing in late summer and fall, they send food reserves into storage. So they should have nutrients available to them during fall as well. We sometimes call this late fall fertilization. This can be advantageous for woody trees, shrubs and even lawns.             Generally speaking we can fertilize most plants once in the spring, now, and be done with it for the remainder of the year. Flowering plants that we appreciate for their flowers need to be fertilized a bit more often; once prior to new growth and then again after blooming to help build up reserves. So your iris probably fit into the second category. The others, into the first category. Apply the fertilizer close to the source of water that is irrigating the plants and let the irrigations take the fertilizer into the root zone.

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Crocus and Tulips Coming Up Early and Protection from Freeze

Leave a Comment / bulbs, freezing weather, winter protection /

Q. My crocuses and tulips are poking their heads out of the dirt in my garden. They’re growing. We have had great “spring weather” in January. Should I let them continue or should I put some more dirt on them? A. Don’t do anything to them. They should be fine unless we get some unusually cold weather for this time of year. If you get nervous because of some predicted cold temperatures, just lay a sheet or light blanket over them until it warms the next morning.             Next winter in December you might cover them with a layer of loose mulch such as wood chips a couple of inches thick to help keep the soil cool and reduce their response to warm weather. This will help slow them down in cases such as these where we have warm January weather.

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February Todo List for the Orchard and Fruit Trees

3 Comments / what to do to fruit trees in February /

·       Pruning should be mostly finished by February 1. You have a little bit more time for grapes, pomegranates and figs. I like to prune grapes as late in the season as possible to avoid any late freezing damage to the spurs. Thrips damage to nectarines ·        Irrigations should begin weekly as soon as new growth appears. The number of minutes depends on the irrigation system and how many gallons per minute or gallons per hour the system delivers. Drip irrigation is in gallons per hour. ·        Begin spraying nectarines for damage to the fruit by western flower thrips. Damage is heavy scarring and droplets of sap coming from the fruit. Do not spray during bloom but immediately after the petals fall from the flowers. Use Spinosad in rotation with insecticidal soap and Neem. ·        Fertilize overwintering onions and garlic with high nitrogen once a month. Garlic and onions will resume growth with warm temperatures. Lightly fertilize garlic as it begins growing again. Onion transplants are normally planted around mid-March and should be fertilized with high phosphorus when transplanted and nitrogen a few weeks later. ·         Prepare smoking wood from prunings. The Orchard has smoking and grilling fruit would available at very reasonable prices. Wood includes peach, apple, pear, fig and others. ·         Fix rabbit holes in fences particularly asparagus. Birds will damage the leaves of broccoli and cauliflower but usually not the heads. ·         Lightly fertilize winter vegetables monthly with your favorite high nitrogen fertilizer. ·       Spray emerging and growing vegetables weekly with insecticidal soap. Make sure you spray on the undersides of the leaves. ·         When you put vegetable transplants in your garden make sure you apply Bt (Dipel or Thuricide) for cutworm control. Spray or dust the soil surface around transplants after planting. Repeat it according to the label until transplants gain some size. ·         Irrigate vegetables as needed. New transplants or emerging seed will need to be irrigated daily until you see strong growth. Established vegetables can be irrigated every two or three days. ·         Be sure to apply a surface mulch after planting vegetable seeds, particularly if they are small like radish, carrots and lettuce. Persimmon response to compost applied to the soil ·         Check irrigation lines and vegetable plots for leakage. Tighten drip tape so there are no kinks in the drip tape. ·         Apply two, 5 gallon buckets of compost around the persimmons. They really liked compost. ·         Harvest asparagus about once or twice each week right now. As air temperature increases you will be cutting more often. When temperatures reach the high 80s or 90s, expect to cut daily. Cut off spears 1 inch below the soil surface. ·         Begin pruning grapes in February. Prune last year’s growth back to 18 inches and finish pruning grapes to one or two buds at the end of February. Table grapes are slower to emerge and can be pruned later than wine grapes. Grape cutting ·         Take grape cuttings to start new plants. Cuttings should include three buds and be the diameter of a good-sized pencil. When taking grape cuttings, make the bottom cut straight and the top cut angled so you know which end should be planted up. Be sure to label the cuttings. ·       Tighten grape trellis wires and refasten the cordons tightly to the cordon wire. ·       Write labels for vegetable seeds that were ordered. ·        Dig blackberries and plant them in 5 gallon containers with a bamboo stake to hold them erect. ·      Watch for tent caterpillar in apricots and plums. Apply Bt or Spinosad if you see them starting to form a nest. ·       Check irrigation bubblers for blockage. ·       Move straw bales to vegetable plots for mulching. ·         Monitor weather temperatures for freeze losses to fruit. If you see freezing temperatures, look in the Orchard to see which fruit trees have flowers which are open. These will be the most sensitive to freezes. ·         Begin weeding vegetable plots.

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Work and Preemergent Herbicides for Rock Garden Weed Problem

2 Comments / rock garden, weed barrier, weed killers, weeding /

Q. I have a rock garden that is ten years old.  We have fabric under the rocks to prevent weeds, but I seem to have more weeds each year.  Could you recommend any effective pre-emergent herbicides? Weed seedlings A. This will sometimes happen for a couple of reasons. These fabrics do degrade over time and some last longer than others. Those with a tighter mesh usually last longer than those with an open or woven mesh. Landscape fabrics should be overlapped so there are no gaps when it is installed. I am assuming you did all of that.             There are some weeds they just don’t prevent such as Bermudagrass and nutsedges or nutgrass. The key to controlling these is to remove them as soon as you see them when they are young, and don’t let them get older or they just get stronger and more difficult to control.             Over time, dirt and dust accumulate in the rocks on top of the fabric and provide a place for weeds to grow. Some rock mulches, like decomposed granite or sandstone, degrade over time. Sandstone is the worst. As these break down and decompose they leave debris on top of the landscape fabric. This is a place where weed seeds can germinate.             It is always best to get rid of these weeds as early as you can and don’t let them get to the point where they flower and produce seeds. The seeds are spread all over the place. I always look at chemicals as a last resort. If you can spend a few minutes once a week just pulling weeds, 95% of the weeds that you see will pull easily. Pull them just after an irrigation and most will pull easily.             In the same way, 95% of the weeds are most likely annuals. If you can kill the tops before they flower this will reduce the weed population tremendously. There are sprays that will “burn” the tops down and thus prevent flowering and consequently seeds.             When we start talking about weed killers, we have to pair the weed killer with the weeds we want to kill. If we pair the wrong weed killer with a weed, it won’t work and we blame the weed killer. So it is very important to know which weeds you are trying to fight.  Both contain Surflan but you would not know it unless you read the ingredients on Impede             However, there are a few we killers that can kill a wide range of weeds, but again not all of them. Pre-emergent weed killers, aka pre-emergent herbicides, include a variety of products with many different marketing names. Some of the lesser known brands have the same ingredients as more expensive products but are not marketed as well.             The pre-emergent products that you can get from your local nursery or supplier are going to be general, all-purpose pre-emergent herbicides. For instance one product by Monterey is called Impede. It contains Surflan which is a very good pre-emergent herbicide.             I don’t know it by its trade name, Impede, but I do know its active ingredient which is Surflan and that is a very good broad spectrum product. Other ingredients you can look for in the labeling that control a wide range of weeds are Dacthal, Ronstar, Goal and Treflan.             Be sure to read the directions and follow them precisely. 

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Almost All Plants Like Wood Mulch – Even Desert Plants

2 Comments / benefits of mulch, desert landscape, yellow plants /

Roses don’t like rock mulch Q. I heard it is best to move rock away from my shrubs and replace it with mulch.  What is your recommendation? A. Rock can also be a “mulch” and we call it that in our desert landscapes; rock mulch. We have three categories of mulches; organic, inorganic and living. In the organic category are wood mulches. In the inorganic category we have rock mulches. All mulches are important but organic mulches, like wood mulch, give extra benefits to plants that rock mulches cannot.             Our desert creates its own rock mulch and that’s why plants that originate from desert environments can “tolerate” rock mulches. It is not that they grow better in rock mulch but rather that they survive better in it.             Nearly all plants grow better with organic mulch rather than rock mulch when grown in our desert soils. Plants like most of our fruit trees, roses, iris, lilies and those which are not true desert plants, perform better with wood mulch. Mockorange yellowing in rock mulch             Those that come from desert climates like mesquites, acacias, desert bird of paradise, agaves, cacti, etc. will tolerate rock mulch better than nondesert plants. But in most cases they still perform better surrounded by wood mulch.             Newly planted trees and shrubs should have wood mulch kept away from them a distance of about one foot the first few years of their life. After that they usually tolerate wood mulch in contact with their trunk. This is because the wood mulch keeps the soil too moist and can cause the trunk to rot when they’re young.

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