Battling the weedy invaders after the fire

A touch of green appears in the blackened ash-strewn landscape in the aftermath of Carson City's Waterfall fire. Is this a reason to rejoice? Perhaps. Some of the green showing is resprouting rabbitbrush, wild rose, willows, grasses and other desirable plants. However, there are also aggressive noxious weeds coming in.

Russian knapweed is one of these noxious weeds rearing its ugly head. With so many areas denuded of vegetation, it is able to recolonize rapidly, growing 14 inches or more in the month or so since the fire. This perennial plant comes back each year from dense colonies of widely spreading roots that can penetrate to a depth of 8 feet. Root sprouts are very aggressive and require both chemical and cultural control for years. The fire merely burned off the tops of these plants, added a little fertilizer in the form of ash, and encouraged new growth. Unless treated immediately, these dense colonies will totally displace native species for years to come.

This weed is as noxious and invasive as the notorious tall whitetop. It is also toxic to horses.

Currently, 47 plants are listed as noxious weeds in the state of Nevada. The ones that pose the biggest threat in this area are tall whitetop, Russian knapweed, diffuse knapweed, spotted knapweed, yellowstar thistle, hoary cress and a variety of thistles. Left unchecked, these plants will outcompete our native plants, using up valuable water and soil resources. They can completely take over sites, destroying wildlife habitat, lowering property value, and decreasing effectiveness of the entire ecosystem.

It is an important point for us to realize that spraying weeds is only one step in the long battle of reclaiming the land for native plants and pasture. One weed specialist in Wyoming says, "I spent the first half of my career trying to kill weeds. I spent the second half trying to replace them with a more desirable plant."

When we try to control weeds, a critical step is the revegetation effort. We need to plant desirable species that will succeed in the area and help keep out the bad guys!

Everyone in the community needs to be on the lookout for noxious weeds. If you find something you are suspicious of and need it identified, bring in a sample to me or your local Cooperative Extension office. Note the location in case we need to do a site visit. Visit our Web site for pictures of noxious weeds: http://www.unce.unr.edu/pubsearch3.asp?Searchby=topicsearch&Searchtext=wanted.

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If you want to learn more about being a weed spotter and learn how to use GPS equipment in that effort, contact me at 887-2252 or skellyj@unce.unr.edu.

If you want information on other landscape and gardening topics, call me or your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu. You may also "Ask a Master Gardener" by e-mailing mastergardeners@unce.unr.edu.

JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.