Issue: December 2, 2000

• Native New Mexico Pines/Christmas trees
• Why does grass die in winter?

Native New Mexico Pines/Christmas trees

What types of pines grow in New Mexico, and what is the typical pine tree used locally for Christmas trees?

There are several pine tree species native to New Mexico. The most common are the pinyon and ponderosa pines, but there are also bristle cone pines, limber pines, and Western white pines. Of the true pines cut for Christmas trees, pinyon pines are the most common. Many people don't distinguish between true pines (genus Pinus) and other evergreen conifers. Many junipers are cut for Christmas trees in New Mexico as are many spruce, Douglas firs, and white firs. There are good books in the library to help you distinguish one species and genus of conifer from the others. Regardless of the type of tree, be sure to keep it moist while inside and out of direct heater vent airflow. To prevent any fire hazard, do not keep it inside too long. Of course, do not put burning candles on or near the tree. Make sure the tree cannot fall over into an open flame or heater which can ignite the very flammable tree.

Have a joyful Christmas with your safe, New Mexico Christmas tree.

Why does grass die in the winter?

Why does grass die in the winter? Jeremy Baker

This is an interesting question. I assume you are asking about lawn grasses, but first I want to discuss grasses in general.

Some grasses are annual grasses. Some of these are common weeds; others are important crop plants such as corn and wheat. These annual grasses live for a single growing season and die. They are genetically programmed to die at the end of their growing season.

Our common lawn grasses are usually perennial grasses. That means that they grow for several years. However, during cold or dry weather, they may become dormant (or quiescent) and appear to have died. The crown of the plant (where the leaves and roots meet) remains alive but dormant. As long as the weather is unfavorable, they remain dormant. Our lawn grasses regrow from the perennial crown. So, these haven't really died.

Finally, some of our perennial grasses die during the winter. They are not supposed to die, but due to damage from insects in the autumn or improper irrigation in the winter, they die in the winter and cannot resume growth in the spring. This is often seen as dead spots in the lawn in the spring. Remember, the perennial grasses are alive in the winter and still need moisture. They don't need to be irrigated as often as in the summer, but a good irrigation once a month is important if the soil is dry and there has been no rain.

Damage from white grub worms shows up most often in the spring as dead grass. Winter irrigation is important in this situation to protect grass which has been weakened by the grubs feeding on their roots. However, treatment with chemical insecticides or biological control agents to control grubs is necessary in the late summer and fall to prevent injury to the grass. Such treatments can help you avoid dead grass in the spring.

Send gardening questions to Southwest Yard and Garden, Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu or at https://www.facebook.com/DesertBloomsNM/. Please include your county Extension Agent (aces.nmsu.edu/county) and your county of residence with your question!

For more gardening information, visit the NMSU Extension Horticulture page: desertblooms@nmsu.edu.

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, office: 505-865-7340, ext. 113.