Top Invasive Ornamentals in Colorado

Invasive ornamental weeds, be>myrtle spurgecause they are so much more attractivethan some of the other noxious weeds, are less likely to be seen as problematicplants. "But they are so pretty," people cry. Perhaps, but these pretty plants are just as descypress spurgetructive to native ecosystems as their uglier friends.

There are at least fifteen plants on the Colorado Department of Agriculture Noxious WOrange Hawkweedeed list that can be considered attractive. Three ofthese weeds, myrtle spurge (Euphorbia myrsinites), cypress spurge (Euphorbia cyparissias), and orange hawkweed(Hieracium aurantamarisktiacum) are on "List A". This means that they have relatively small populations and must be eradicated everywhere in Colorado, including municipalities.

Thrussian olivee remainder are "List B" weeds, which have a different designation in each county. Some of the worst offenders on this list include tamarisk (Tamarix ramosissima) and Russian olive (Eleagnus angustifolia), trees which take over the banks of streams and rivers, depleting water courses and out comYellow Toadflaxpeting native riparian species. Perhaps the three most problematic herbaceous plants are oxeye daisy (Chrysanthemum leucanthemum), and yellow and Dalmation toadflaxes (Linaria vulgaris, and L. genistifolia). All of these naturalizDalmation Toadflaxe readily, crowd out native plants, and are unpalatable to livestock.

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Updated Monday, February 01, 2016