Issue: November 17th, 1997

Scrawny pampas grass


This year I've noticed that the plumes on many of the pampas grasses in town are quite full and fluffy. However, when I look at mine, the opposite is true. Each year the fire department comes and burns my pampas grass as well as my neighbor's grass. Could this be the problem? Please tell me what I may or may not be doing to make the plumes so scrawny.


I am assuming that in the past your pampas grass had nice, full plumes. If that is the case, I would suspect that trees in the vicinity have matured over the years and are shading the pampas grass which needs full sunlight for a large part of the day. The trees may also have increased in competition for water and nutrients as they have grown larger and their roots have spread. Another possibility is that the clumps of pampas grass have become too large and the pampas grass is competing with itself. Pampas grass will often develop a dead center with a ring of living pampas grass as this happens. If you think this is the problem, you may wish to divide the clump in the spring before growth begins.

Another consideration is any change in culture. Have you reduced watering or increased fertilization? Too little water can reduce the vigor and flowering of the pampas grass. Too much fertilizer will stimulate excess growth at the expense of flowering. This may result in scrawny plumes.

If your pampas grass has never been particularly good at producing plumes, then you might consider whether or not there is a soil problem where you planted it. Salt, especially sodium salts, are a problem in some parts of Roswell. A soil test to determine salinity, as well as nutrient levels in the soil, may be useful in determining the exact cause of your problems. Your local Cerative Extension Service office can help you arrange for a soil test.

Plants good or bad for sick people?


In school I learned that plants produce oxygen from carbon dioxide. Now a friend tells me that houseplants and cut flowers do the opposite and should not be place in a room with a sick person. What is the truth?


Where there is sufficient sunlight, houseplants produce oxygen and absorb carbon dioxide from the air. The carbon dioxide is used to create carbohydrates and other materials for the plant. The oxygen is a by-product of the light reaction of photosynthesis in which water is split into hydrogen, used to make the carbohydrates, and oxygen, which is released into the air. Since photosynthesis, especially the part producing the oxygen, requires light, the release of oxygen ceases in the dark or in dim light.

Plants also respire, as do animals. In respiration, oxygen is consumed and carbon dioxide is released. This occurs in the dark and the light. During the day, more carbon dioxide is consumed by photosynthesis than is produced by respiration. At night the production of carbon dioxide is greater.

However, the production of carbon dioxide is not the reason for concern regarding the placing of plants in a room with an ill person. The concern here is that the fungi and bacteria in the soil, and especially in the water of cut flowers, could further endanger the health of the ill person. This would be a special concern when the person has a weakened immune system. However, it is known that flowers and houseplants lift the spirits of ill people and contribute to healing. Your doctor should be consulted regarding the need for concern regarding houseplants and flowers in the room. A healthy person need not be concerned at all unless they happen to have allergies to the fungi in the soil of houseplants.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!