April Showers Bring May Flowers (and Weeds)

Time is of the essence for getting some of our worst noxious weeds under control. Cheatgrass and Siberian elms need to be controlled this month. Here are some tips for getting it done.

The ample winter and spring moisture we’ve been enjoying is a double-edged sword. Our wildflowers and gardens are waking up and flowering with vigor, encouraged by moist soil. But the moisture has also caused an explosion of weeds.

Cheatgrass (Bromus tectorum)

A horribly invasive species from Eurasian is an annual grass that has taken over many parts of the western US and is widespread around Santa Fe.

• Its seeds are highly dangerous to pets lodging in their ears and skin. The barbed seeds move one way and will puncture eardrums, penetrate the skin and work their way into the body.

• The dried grass is also highly flammable and represents a very real hazard in June.

• Look for cheatgrass in shaded areas; under native shrubs (Chamisa especially), under Siberian Elms and shaded north-facing slopes are favorite venues where it grows. It is also found in full sun growing in roadside ditches.

• You can pull it.

• You can spray it with natural, non-toxic herbicides like Burn-Out Formula II. A mixture of citric acid and clove oil, this is very effective for killing annual weeds like cheatgrass. Spray them now before the seeds ripen.

• But when there are just too many grass plants to pull or spray, a well-timed mowing is highly effective to prevent the grass from ripening seeds which are numerous and last in the soil for years. Mow it too soon and the grass re-sprouts and the flowering seedheads that are too low to re-mow. So wait until the seed heads turn purple to cut them down. This will be happening toward the end of May (or sooner at lower elevations).

Siberian Elm (Ulmus pumila)

This incredibly invasive Eurasian tree had a banner year last summer, with the monsoon rains germinating their seeds that drifted down from the trees last May.

• The seedlings are everywhere and will grow quickly this summer. So it’s very important to go around your yard now and pull the little ones. Note how long the roots are even when the plant are small!

• The soil is reasonably moist which makes pulling these deep-rooted seedlings more doable.

• Once the saplings reach several feet in height they are impossible to pull and must be cut to the ground and the small stump painted with an herbicide like Fertilome® Brush and Stump Killer. Otherwise, the cut saplings will quickly re-sprout and continue to grow into large trees.

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