PINYONS AND CALICHE

by Curtis Smith, Ph.D.  

Q. I was wondering if your could look at this picture and tell me what the two things are that are growing on the pinyon pine tree. Are either harmful to the tree?

A. Your picture shows two forms of lichen, a symbiotic association of fungi and algae. The forms you show are a gray/silver foliose form and a duller silver/green foliose form. Foliose means that they look like they have leaves, when actually these are not true leaves. There are other forms that do not look like these, and there are many colors ranging from silvery, greenish, yellow, and even red-orange. In all cases they use trees, rocks, and in some instances even telephone lines as a substrate upon which to grow. They do not extract nutrition from the plant parasitically, thus they do not directly harm the tree. This is obvious if they can grow on rocks and telephone lines.

Lichen absorbs nutrients from the surface of the substrate and from the air (dust). Moisture is obtained from moisture in the air. All forms of lichen need sunlight but can grow in quite shady places.

Often it appears that they are damaging a tree because they grow better on a tree with declining health than on a healthy tree. However, they are not the cause of the tree’s decline - they only benefit from the tree’s bad fortune. An unhealthy tree allows more light to penetrate to the bark, and this is beneficial to the lichen. Sometimes a tree with declining health leaks nutrients and sugars which become available to the lichen once it is outside the tree. Consequently, the lichen on the unhealthy tree grows better and looks like the culprit.

This is a clue that you should investigate other factors that can cause tree decline. Insufficient water, disease, and insect attack are likely causes of poor tree health. Last summer was a dry summer, and many trees are exhibiting symptoms of drought injury this year. This may be the cause of excess lichen growth in some natural and home landscape settings.

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Q. I moved here from the Midwest. My neighbor explained that the reason I had trouble with my garden this year is that my soil is “caliche” soil. What is caliche soil?
Artesia

A. Caliche is a term used often in New Mexico when speaking of soil. I think some people just mean the soil is very calcareous; that is, the soil contains a high level of calcium and has a high pH (is alkaline). Others think of caliche as a layer of rock (limestone) at some level below the surface of the soil.

I spoke to Dr. Robert Flynn, NMSU Extension Agronomist, about this, and he gave me some specific definitions which are important for gardeners to understand their soil. Caliche is defined as an amorphous (non-crystalline) mass of calcium carbonate (limestone) mixed with clay. The cement-like layer below the soil surface that is often called caliche is termed a “petrocalcic horizon” by soil scientists.

Many New Mexico gardeners will find that their usable soil depth is affected by an impermeable petrocalcic horizon as some depth below the soil surface. This affects drainage and can provide a source of calcium to thwart efforts to alter pH. This will also influence shrubs, trees, and other deeply rooted plants. In order to learn the specific soil conditions influencing your garden, it is wise to send a soil sample to a soil-testing laboratory. This will provide information about soil physical and chemical characteristics allowing proper management of the soil.

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Q. I want to grow some culinary herbs on my windowsill during the winter. What should I do?
Taos

A. You should carefully choose the plants you will grow based on the size and location of the windowsill and the herbs that you will find useful. Chives and bunching onions are easy to grow on a windowsill. Only a little of these herbs goes a long ways in cooking, but that is true of most herbs. They will do best in a south-facing window, but east-facing or west-facing will also work.

I have successfully grown basil through the winter in a south-facing window, though many books say that they don’t make good windowsill plants. Rosemary, thyme, and many other common herbs may also be grown in a windowsill.

Carefully inspect the plants for insect infestation before bringing the plants indoors. It is a good idea to grow them outside a while after purchasing the plants to allow insect eggs to hatch before the plants are brought indoors. Watch for any symptoms of disease. Insects and diseases are much easier to treat outside, especially if chemical pesticides are needed. Be careful to choose pest control products that will not leave a residue on the leaves that you will be eating later in the winter. It is also possible to start many herbs from seed, but don’t let plants brought in from outdoors infest them.

Once the plants are indoors, water carefully. As the weather changes and the furnace runs more, the plants will dry more rapidly.

Windowsill herbs are an easy way to continue gardening in the winter and to enhance the flavor of your meals. Happy winter gardening.

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Q. I recently landscaped my townhouse courtyard with pots of Pretoria Canna and Big Leaf Philodendrons. They were full, beautiful and blooming. I have no patio cover and the pots sit on Saltio tile because there is no dirt. I think the tile draws heat to the plants. I have sprayed them daily and watered them enough to keep moist. The leaves on the plants look burned, and the plants are not producing any new leaves. What do I need to do before I lose them completely?
Karron B.
via internet

A. The plants that you described are from understory locations in the tropics; that is, they are adapted to shade and have a really tough time with direct sun, especially in the Southwest United States. The heat does complicate things but is not the primary problem. The leaves are just sunburning.

The solution is shade. Some trellises placed in five gallon buckets or large flower pots and positioned to shade the plants, especially from mid-day until late afternoon, will help. The trellises alone may make enough shade, but vines planted on them will help more. Be sure to choose vines adapted to full sunlight locations, or for immediate benefit use artificial plants on the trellises this year.

Continue to provide adequate water and moisten the tiles during the day as you have been doing. The damaged leaves will not recover, but the plants should produce new leaves if they are not too severely damaged.

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Q. I am hoping you can help me with a problem. I have just moved to the East Mountains from Illinois and need some help figuring out how to grow tomatoes here. I brought the tomato plants with me from Illinois, and they look like the healthiest plants I have ever grown. They are in tomato cages, and I have not pinched off side sprouts. In Illinois, by this time I should be having ripe tomatoes, but here there is not a single tomato set on the five plants, and very few blooms compared to what is normal. Can you give me a clue as to what is wrong and what I can do next year, if not this year, to rectify it? One person suggested that tomatoes won't set because it gets too cool in the nights here. I would greatly appreciate any help you can give me.
Kathy A.
East Bernalillo Co.

A. There is probably more than one factor working here. First, our summer day temperatures kill the tomato pollen, so even when the plants are flowering, there is little to no fruit set. This is variety dependent - cherry tomatoes, saladette, and other smaller varieties usually set better at high temperatures and often have a crop set before high temperatures develop. The varieties that produce larger fruit have more difficulty.

Low night temperatures can reduce flower development. Your statement that these were the best plants you have ever grown indicates good growth and perhaps high nitrogen fertilization (from commercial fertilizer, manure, and some composts). Nitrogen coupled with low night temperatures may reduce flower development, and high day temperatures may prevent flower set.

Growing several different varieties (of different size tomatoes) gives you a better chance of having fruit set. Don't make the soil too rich, nitrogen is needed, but balance with phosphate fertilizer. Choose varieties that will produce a lot of leaves. (Temperatures will be warmer under the foliage at night and cooler in the day time).

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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.

Questions or Comments? Email editor@nmjournal.com