Xtremehorticulture

Xtremehorticulture of the Desert

Using Ficus as a Hedge/Screen Around a Pool in Phoenix

Leave a Comment / cold damage, definition horticulture desert, ficus nitida, freeze damage, heat, pool screen, privacy, screening /

You scared me for a minute. I’m in Las Vegas so when I saw your Ficus mentioned I was concerned. I am less concerned with it in the Phoenix area but the pool area puts it in a different twist and you still have to worry about freezing damage.             But I am going to copy this to my good friend Terry Mikel who was your Extension Specialist in Maricopa County with the main office in Phoenix. He is better at answering this one and I will post his answer. He is in retirement but I am SURE he will come out of hiding on this one! Q. I live in Glendale Arizona. I have a 45ft section of 6 foot brick wall that I would like to plant Ficus nitida along. There is a 4 foot width between the wall and a plaster underground swimming pool. No problem watering the hedge?  But will this plant seek the pool water and cause a problem. I am not worried about frost. I want a 10 foot hedge when done. A. Your thoughts about having a hedge sound good.  Ficus microcarpa sub species/or cultivar ‘Nitida’ can fit the situation; its clean (no real messes). evergreen and makes a dense wall of foliage.             I have to use the term ‘can’ with a couple caveats.  1. This plant can grow to a very large size.  Frosts every few years help keep them in check.  And pruning can, to a certain degree keep them in check.  But, frosts and pruning will be a continuous battle against their genetics: it wants to be a 60′ tall and 80′ wide tree. 2. This species of Ficus will after time develop huge surface roots that will lift, push or barge anything in their path.  It’s their genetics and watering will have little, if any affect so the wall to the one side and any pool decking on the other side will be vulnerable to the large lifting roots.             Your one concern about them ‘seeking’ water is a commonly misunderstood trait of any plant. . . Plants do not search out water, period.  Plants send out roots randomly in all directions and roots that run into a water source will proliferate.             Pool sides, if sound will be the same a rock in nature, the roots will try to grow up, under, or around any solid object.             If, and this is a big if there is the slightest oozing leak from the pool’s wall  and a root meanders there then it will grow and proliferate in response.  That’s where the issue of roots and pools becomes a problem.             Personally, the Ficus is overused and most people who grow them quickly tire of all the problems with them.  If anyone who knew much about them would warn folks against using them except for large evergreen tree.             Your setting is a little bit of a challenge. You might think about something much less vigorous with fewer potential problems and some have blooms (a potential ‘mess’ issue). Look at: citrus, Hop Seed Bush (Dodonea), Xylosma (both common and botanical name), Arizona Rosewood (or any in that genus of Vauquelinia), one of the many different blooming colors of Arizona Yellow Bells (Tecoma and various species and varieties), Petite Oleanders have been used in that setting for generations.             Every person’s ‘likes’ and ‘dislikes’ vary. Check with your water department and pick up some of the nice booklets about planning and plants for the landscape. These were produced by the Arizona Municipal Water Users’ Association, more lovingly called AMWUA to be distributed in the different communities.             Another resource might be going to the Mountain States Wholesale Nursery (MSWN.com) site for a truly complete list of plants that are well adapted in the lower Sonoran desert. They also produce some for the higher deserts but their main goal is for lower deserts. . Respectfully, Terry H. Mikel

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Growing Saffron in the Desert

12 Comments / desert production, herbs, spices /

Q. I live in Summerlin and I want to grow saffron crocus. Is our area suitable for the successful propagation of this plant? If so, can you tell me the best source for the sativus corms? I would like to plant in the early spring if possible. Saffron crocus growing at the orchard A. Yes, saffron will grow here and does quite well. Saffron, a type of crocus is in the iris family, is one of the most expensive spices in the world. It takes about 60,000 crocus flowers to make one pound of saffron. One of our volunteers began growing it successfully at the orchard a couple of years ago.             There is no seed so propagation is by planting the bulb which is actually a corm much like a tulip bulb. Your best source for corms for planting will be online. Saffron crocus loves our alkaline desert soils, hot dry climate and mild winters. It does well in climates and soils that can grow pistachios.             The bulbs of saffron should be planted in full sun in heavily composted desert soil with additions of your favorite phosphorus fertilizer. Planting should be about 4 inches deep and about 4 inches apart. They should be irrigated and mulched with light mulch such as straw. Lightly fertilize continuously through the season to increase bulb size so it can be further propagated.             There are different levels of quality in saffron usually based on its color and taste. You can affect the quality of saffron by manipulating how it is grown. Grow it so it is “happy” and it will produce a good quality product. Saffron production manual

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Can Myers Lemon Do Well in Rock Mulch?

Leave a Comment / desert landscape, fruit trees, rock /

Q. I live in the far western area of the Las Vegas valley.  I have a good sized area covered with rock mulch. A flowering plum tree (soon to be removed) is struggling in this area. Can a Myer’s lemon tree do well in a rock mulch setting? Loquat in rock mulch A. I would not recommend it. It might do okay for a few years, maybe 3 to 5, and then it will start to take a dive. You will have much better luck if you can pull the rock away from fruit trees, including your flowering plum, perhaps 6 feet or so from the trunk and putting down wood mulch instead of rock.             If you decide to plant some citrus, I would highly recommend adding a lot of compost to our desert soil at the time of planting. It is much more effective to mix it in the soil then it would be to try to add it to the soil after it has been planted.

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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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