High Elevation Gardening Web Log "Blog"

Technically, exotics are everywhere in Flagstaff, such as tulips, daffodils, and Kentucky blue fescue. The real problem is not plants "from away", but invasive and thus noxious plants "from away." Artichokes and Scotch thistles are both exotic thistles. Both have beautiful flowers, but the Scotch thistle is inedible, thorny, invasive, and noxious, while an artichoke isn't and is delectable. An artichoke, a benign exotic, generally doesn't survive the winter and doesn't crowd out native plants.

Some of these invasive and noxious exotics are winsome at first glance. The Dalmatian toadflax is quite attractive, resembling a yellow gladiolus. Originally introduced to the United States as an ornamental, it has become a pushy noxious weed crowding out the natives. Indeed, a whole field is quite fetching, only they're that attractively bad company about which mothers repeatedly warn their children.

While some are fetching and others repulsive, they play havoc with the natives, destabilizing the relations between various native plants, trees, and wildlife. Birds are deprived of seeds. Squirrels lose their nuts and berries. In addition to being pushy, many are water hogs, such as the tamarisk, sucking up copious amounts of water, depriving the natives of an already sparse supply of water. A triple threat, tamarisks are ugly, pushy, and hydro-addictive.

The Colorado Plateau, with Flagstaff sitting on its southern edge, is a delicately balanced system of mutual support for animals, birds, grasses, plants, and trees. The system presupposes drought, cold, and altitude. In a harsh climate that has taken aeons to develop, invasive and noxious plants threaten the stability of a delicately balanced system which if unchecked could cause the system's collapse. They're weeds, and they're unwanted.

They're unwanted for several reasons. First, they use scarce water thus depriving the native plants of needed water. Second, they crowd out the native plants which are a part of a biological community including birds, animals, and trees, threatening the community's stability. Ironically, since the exotics are from away, the native plants aren't able to compete with them, the exotics being more aggressive. They produce more seeds, disperse them efficiently, and out-grow the natives. Also, they don't have any natural adversaries to keep them in check. They over take and take over.

Third, some of them are poisonous and a threat to wildlife and domesticated animals, such as dogs and cats. Cheat grass has microscopic barbs which play havoc with an animal's digestive and pulmonary systems as well as their eyes and ears. The yellow starthistle if eaten with its barbs leaves an animal unable of eat, and if unattended is fatal.

Fourth, one of the most severe consequences of these invasive and noxious weeds is the disarray they cause in the natural patterns of wildfires. When the cheat grass has dried out in the fall, it is tinder for fires.

Getting rid of invasive and noxious exotics is not simply the task of rangers and eco-nuts, but of everyone. Human beings have chosen to live in this delicately balanced system because of its many benefits, and as good guests they have to pick up after themselves, clear the table, do the dishes, and flush the toilet. After all, these exotics result from human intervention. Here's a list: diffuse knapweed, Russian knapweed, yellow starthistle, Dalmatian toadflax, Scotch thistle, hoary cress, bull thistle, cheat grass, and tamarisk. Wearing gloves, pull them out, root and all, put them in trash bags and dispatch them to Environmental Services.

For mug shots of these culprits click: http://cals.arizona.edu/coconino/nr/invasiveweeds.pdf
Dana Prom Smith, a Master Gardener volunteer and coordinating editor of the Master Gardener Column for Coconino County Cooperative Extension, can be contacted at stpauls@npgcable.com. For gardening questions, call the Master Gardener Hotline, 774-1868, x19, or visit MG Web site: highelevationgardening.arizona.edu.