Issue: September 24, 2005

What is Chenopodiaceae? | Fall tree and shrub planting

What is Chenopodiaceae?

Question:

When I looked at the pollen alerts recently, I noticed a category "Chenopodiaceae" or on another list "chenopods". What is this, and how does it relate to my allergies?

Answer:

The term Chenopodiaceae is the family name for a large group of native and introduced plants. The term chenopod is a simple way to write and pronounce this family name. The plants producing the pollen referenced in the alerts are not all in the chenopod family but are closely related. They all produce pollen grains that look the same and cannot be distinguished from each other under a microscope. All are predominantly wind-pollinated. This means that they produce large quantities of pollen which is small and easily dispersed by wind. Some other plants with pretty flowers are usually insect-pollinated and produce larger, heavier, sticker pollen. The insect-dispersed pollens may cause allergies in some people but are not as easily dispersed as the wind pollinated hay fever plants.

These are plants that blossom in the summer through the fall season and are contributors to our fall allergies. They include the tumbleweeds (Russian thistle), four-wing saltbush (Atriplex canescens) and related desert natives. This group also includes pigweeds (in the related family Amaranthaceae).

Some of these are weeds, and others are very common native desert plants. All are very common and impossible to eliminate over the whole state. However, by eliminating the weedy members of this group from your landscape and garden, you can reduce the level of exposure to their pollens and perhaps diminish your discomfort.

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Fall tree and shrub planting

Question:

Is it a good idea to buy trees and shrubs that are on sale at nurseries in the fall? Is fall a good time to plant them?

Answer:

If the trees and shrubs have been well cared for in the nursery and are placed on sale for clearance, now is a good time to buy and plant them. If they were not well cared for and appear to be in poor health, avoid them.

Trees and shrubs purchased in the fall are more likely to be root bound (an abundance of roots in the pots, with many of them circling the edge of the root ball). These circling roots must be cut at the time you put these plants into your landscape. If you don't cut the circling roots, you will probably see problems developing from root girdling and poor root development in a few years.

With the above warnings in mind, fall is a good time to plant trees and shrubs because their roots will often continue to grow in the fall after the leaves have dropped. Remember to water the new plants, but don't overwater. Once the leaves have dropped, less water is needed by the plants and as the temperatures cool, evaporation of water from the soil is decreased. A few plants (such as desert willow) are exceptions. The desert willow does not respond well to winter irrigation and should be planted no later than the end of August.

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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 at 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.