SIBERIAN ELMS
by Curtis Smith, Ph.D.
Q. I have a question regarding what we call "Chinese elm trees" here in Albuquerque, although I'm not sure that is their real name. How can I rid my property of these trees?
Albuquerque
A. The elms to which you refer are probably Siberian Elm (Ulmus pumila) instead of the true Chinese Elm (Ulmus parvifolia). Siberian elm is very common in Albuquerque and has become a nuisance. They are useful trees in areas where trees are desired but care is unavailable. Unfortunately, their profuse production of viable seeds results in elms growing where they are unwanted.
If you cut the tree, there is a good chance it will sprout from the base. Unlike the cottonwoods, it is less likely to produce sprouts from the roots over a large area. Some people have had good success with drilling holes in the stump immediately following cutting the tree. These holes are filled with any of several chemicals labeled for killing tree stumps. A more effective method is to apply the chemical in "frills" or notches made by downward cuts that go just below the bark of the tree. This region of the tree contains the phloem that carries material from the top of the tree to the roots. Chemicals applied in this zone translocate to the roots to kill the roots. There are several products available in nurseries and garden centers labeled for "frill application." The chemical is usually applied full strength in this manner of application. (Read and follow the directions on the label for best results with the chosen product.) After a few weeks, the tree may be removed. It is important not to leave a dead tree standing near homes, cars, playgrounds, traffic ways, or any other place where injury or damage could occur if the tree fell.
If some sprouts develop following application of the product to the trunk frills, foliar spray of a labeled herbicide on the newly developing sprouts should be effective in completing the elimination of the tree.
Q. My tree that I recently bought is looking sick. The leaves on the tree look burned and eaten up. What should I do?
A. A newly planted tree will often look as you have described because it does not have a large enough root system to provide adequate water to the new tree. As a result, the leaves dry around the edges and begin to rip and tear. As the tree establishes and develops a larger root system, this should become less of a problem. In a really windy location, the problem may remain in later years.
For now, just be sure the tree is watered about once a week. Water slowly so the water can soak in deeply and moisten the whole root ball. Don't water too often or the roots will begin to rot. The surface of the soil will dry a lot faster than the soil several inches down.
If you think it is insects eating the leaves rather than wind tattering, take some leaves to your local Cooperative Extension Service office and perhaps the Extension Service Agent can help. However, in most cases it is difficult to identify the culprit from only the leaves.
Q. I have several large areas in my back yard where a white/grayish fungus is on the grass blades. A couple of years ago a nursery suggested Daconil. When I used it the past two years, I don't think it spread very much but the Daconil, about the same color as the fungus itself, made that part of the lawn gray and did not clear up the problem. Recently I noticed the same spots re-occurring plus some other areas. This time the nursery recommends Sulfur Hydroxide. What is really best? Either of these, a combination of both, or something else? The grass is well established, probably about 35+ years old and is mainly a fescue. At least that is my estimation since the lawn was sowed by the previous owner as Albuquerque Mix.
Larry L.
AlbuquerqueA. I wonder if this is really a fungus. Powdery mildew makes a thin whitish coating on the leaves. Powdery mildew can be a significant problem, but can often be managed by reduced night humidity - irrigate early in the morning every third day or so. Some fungicides (labeled for treatment of powdery mildew) can also be used if irrigation scheduling changes can't eliminate the problem. Even so, irrigate in the morning and infrequently to keep the fungus from reappearing.
If it is a thicker grayish coating on leaves of grass over an area less than a foot in diameter, it may be slime mold which is not a real problem and can be washed off with a strong stream of water. Slime mold should not damage the grass (except to exclude light from the coated leaf blades).
The best way to know for sure is to take a sample of the affected grass to the County Extension office and have the agent determine what specific problem is present.
Q. I have three Weeping Willows in my yard that are about four years old. One of them has red & black ants on it. Are they a problem?
Don M.
via internetA. The ants are probably not a major problem, but an indication of other problems. While it is possible that the ants are carpenter ants which can mine dead wood in the tree, it is more likely that the ants are present because there are aphids in the tree. Aphids feed on the sap of the tree and can spread plant diseases. They are likely to be the real problem. Do you see a silvery sheen on some of the leaves? This is the honey dew excreted by the aphids. This is also the sugary substance which is attractive to the ants.
Aphids can often be washed from small trees and shrubs with a strong jet of water from the garden hose. Of course, they will climb back into the tree or shrub, but while climbing they will not be harming the tree. However, even while they are climbing into the tree after being washed out, they are prey for many types of predatory insects. You can use a pesticide, but this will harm the beneficial insects that prey on the aphids. This is a good time to avoid the chemicals if possible.
Q. I have two 2"x12" PVC pipes buried at the dripline of each tree I have planted in my yard, with holes drilled in the side of the pipes and small rocks in the pipes. I have drippers in each pipe. This is how I water my trees. May I administer properly diluted chelated iron directly into the PVC pipes rather than pouring it on the ground around the tree? Is it possible to use these PVC pipes as a way to administer fertilizer, etc. - pouring it down the PVC pipe rather than just on the ground? I’m wondering if this would get help directly to the roots rather than on the grass around the tree?
A. I have heard of this technique since I was a child. There is some logic to the technique - the water is placed below the surface and less subject to evaporation. However, there are problems with this technique as well. You have largely avoided the first problem by not using a longer pipe. However, even a pipe that is one-foot long has you watering below many of the roots. If the pipe was perforated and the drip emitters provided water fast enough to fill the pipe, it would help by allowing some water to escape at different depths.
A second problem is the number of pipes. You have used two, but many more would be better. The larger the tree, the greater the root system. Most of the roots that actively absorb water and nutrients are further from the tree than the dripline. With only two pipes at the dripline, you are providing water to a very small percentage of the root system. If the pipes have been in place since the tree was first planted, the tree may have developed its root system only where the pipes provide water. This is especially true if there is never moisture in the soil at any other location. Nevertheless, the root system is quite limited in this circumstance. At least four to six pipes equally spaced around the tree (at and beyond the dripline) would encourage development of a more extensive root system.
If the soil is sandy, the water will quickly permeate the soil downward, spreading very little laterally. Once the water has permeated the soil to a depth greater than three feet, much of the water is unavailable to the tree and is wasted. A loam or clay soil will allow more lateral movement of the water and less rapid loss of the water below the tree’s root zone. If you use this system of irrigation, the soil type will determine the number of pipes needed.
The lack of distribution will create a problem with the application of nutrients about which you asked. The nutrients will be localized, and there is a possibility of damage to the limited root system when fertilizer is applied to the roots through the pipes. (The chelated iron should not cause damage.) Properly diluted fertilizer will not damage the roots, but remember that the instructions for dilution are not designed for application in this manner. Those directions may allow for too highly concentrated nutrients. If lawn irrigation or rainfall has allowed development of roots outside the zone supplied by the pipes, then you will be providing nutrients to only a small portion of the root system and the effects will be less than desired. Be careful fertilizing your tree in this manner.
Q. I need information on recommended “turf grass”. I will use private well water from a shallow aquifer of the Rio Puerco near Cuba, NM. I heard that Blue Grass takes too much water. I want a grass that has a good appearance, low maintenance, and good ground coverage (sod). Someone told me about “Fescue”, either tall or red fescue. Please help. I am hoping for summer rains to help with seedling establishment.
A. It is important to consider the function of the grass when choosing a lawn grass. You provided some of this information, but there are other considerations. Is the purpose aesthetics? Soil stabilization? Athletic use (children and pets)? It is also important to consider the water available and to determine whether or not you have enough water to support the desired function of the lawn.
Athletic uses, play areas for children and runs for dogs will have the highest water needs. It will be important for them to grow rapidly to recover from damage which occurs during use. However, most home "athletic" uses don't require large acreage so only a small portion of the landscape should be used to grow these grasses. Outside the heavy use areas, lower water demand grasses (slower growing) may be used. If the function of the grass is only aesthetics and/or soil stabilization, you can use the lower water demand grasses.
Kentucky bluegrass does have a high water requirement. However, most people overwater bluegrass because the planting site was not properly prepared. Fescue can get by on a little less water than Kentucky bluegrass if the planting site is prepared to allow deep root development. Buffalograss and blue grama grass have even lower water needs, but again good site preparation is essential. There are some newer grasses (Texas bluegrass and Turtle turf) that are intermediate in water needs.
It is also possible to use other native grasses in the less manicured areas. They will be well adapted to low levels of irrigation and will look pretty good from a distance. They may be mowed a few times a summer to keep them shorter, or they may be allowed to grow and set seed. In all cases manicured lawn or native grass areas, good soil preparation makes a lot of difference.
The soil should be prepared by plowing or rototilling deeply to loosen the soil. Soil is compacted near homes by trucks and other building equipment which had been driven over the site. This compaction must be eliminated. Addition of organic matter in the form of compost (or manure only in the fall) helps grass seedlings to establish and helps keep the soil open. Peat moss or other materials may be used, but they are more expensive. The addition of organic matter will increase the effectiveness of monsoonal moisture in helping establish the seedlings. Don't trust the rains for seedling establishment. They may help, but they may also be too infrequent for successful grass establishment. Be prepared to irrigate briefly several times a day when the seeds are first germinating (skipping an irrigation or two if it rains). The soil must not dry once the seeds have begun to germinate. Later, as the seedlings begin to develop and there is good coverage of the site by seedlings, the frequency of irrigation can decrease and the duration of each irrigation can increase to moisten the soil more deeply to encourage deep root development.
Q. My tomato plant stem is growing all twisted. One is just laying on the ground all flat and twisted. What is wrong?
A. I discussed your question with Dr. George Dickerson, NMSU Extension Horticulture Specialist (vegetable and small fruit crops). I had considered curly top virus as a cause of your problems, but Dr. Dickerson didn’t think you would see that much twisting from curly top. He asked about fertilization. He specifically asked if a “weed and feed” fertilizer was accidently used in the garden or in the lawn nearby. Some herbicides used in combination with fertilizer can cause very obvious curling and twisting of tomato (and other) plant stems and leaves.
If accidental contamination by weed killer is likely, it may be best to remove the plant rather than hope it will manage to mature some fruits. This is because the herbicide is active inside the plant and may also be present in the tomato fruits. Watch for symptoms in other nearby vegetables.
You would also be wise to contact your local Cooperative Extension Service office for more information. If herbicide is not the culprit, your Extension Service Agent should be able to help you diagnose the real problem.
Q. I noticed that there are small fruits forming on my rose bush. Why haven’t I seen little rose bushes coming up under the old rose bush if these seed are good? Can I plant the seeds? How do I need to treat them? Will they grow roses like the plant that produced them?
A. Most people remove the rose hips (fruits) as soon as the flower fades to increase flowering. This prevents the rose plant from directing energy into the production of seeds instead of new flowers.
These seed often have the ability to grow and produce a new rose plant, but the flowers may not be much like the parent. Most of the roses we grow (hybrid teas, floribundas, etc.) are hybrids. That means that there is a mixture of genetics from the mother and father plants. In vegetables, trees and shrubs, gardeners know that hybrid seeds do not produce plants like the parent that produced the seeds. The result may be better or worse but certainly different. If you wish to see what happens, you can plant the seeds.
The seeds will need a period of “stratification”, that is a time of storage under moist, cool conditions. You can provide this by removing the mature seeds from the fruit, putting them in a plastic bag of moist compost, vermiculite, or potting soil. Place this in the refrigerator for about six weeks before planting the seeds in a pot with potting soil. Keep the newly produced plants in a greenhouse or sunny window through the winter, and plant them outside in the spring. In a year or sometimes several years, you will see the flowers produced by your seeds. Remember, the flowers may be very different from the plant from which you harvested the seeds.
Send your gardening questions to:
Yard and Garden, ATTN: Dr. Curtis Smith
NMSU Cooperative Extension Service
9301 Indian School Road, NE, Suite 112
Albuquerque, NM 87112
Curtis W. Smith, Ph.D., is a an Extension Horticulture Specialist with New Mexico State University's Cooperative Extension Service. Dr. Smith and Dr. George Dickerson host Southwest Yard & Garden, a weekly program for gardeners in the Southwest. It airs on KRWG in Las Cruces Monday-Friday at 6:30 p.m., Thursdays at 1 p.m. and Saturdays at 11:30 a.m.; on KENW in Portales on Saturdays at 10 a.m.; and on KNME in Albuquerque on Saturdays at noon and Fridays at 2:30 p.m.
editor@nmjournal.com
Copyright ©2000, 2001 WordPros Publications, Inc. All Rights Reserved. No part of this site may be duplicated in any form without the express written consent of WordPros Publications, Inc. This includes all text, formatting, graphics, photographs, scripts and coding, etc. All brand names, logos, and product names used on these web pages are trademarks or tradenames of their respective holders. Terms of Use.