Noxious weeds in Gilpin County

Sulfur cinquefoil (Potentilla recta)

Photo credits: Washington Noxious Weed Control Board and King County, WA

NEW INVADER TO GILPIN COUNTY!

Quick Facts
• Sulfur cinquefoil is a non-native cinquefoil, or Potentilla that has the potential to become very invasive
• You need to be very careful to distinguish it from our many native Potentilla/cinquefoils.
• Flowers are light yellow (most of our cinquefoils have deeper yellow flowers) and are deeply notched.
• The leaves have five leaflets, and resemble those of marijuana. They are green on the underside, not silver, as are most of our native 5-leaved cinquefoils. The leaf stalks have perpendicular hairs longer than the width of the stalk.

Why it’s a problem
• Sulfur cinquefoil takes over native vegetation.
• It is unpalatable to livestock and wildlife, reducing range and habitat.
• Large stands will reduce property values.
• Seeds can remain viable in the soil for four years.

How to control it
• Small infestations of sulfur cinquefoil can be hand-dug. In Gilpin County, the plant will start going to seed in mid-August.
• It cannot be controlled by mowing, because mowing causes bulky, spreading roots to develop.
• 2-4, D and roundup are effective.
• Hand-pulling can be effective on small patches, especially in gravelly soils when you can pull a large part of the root. It will need to be pulled for several years. Pull before it goes to seed.
• This is new to the county! With everyone’s sharp eyes, we can nip this invasion in the bud, and it will never have a chance.

For more information:

http://www.nwcb.wa.gov/weed_info/Potentilla_recta.html

http://dnr.metrokc.gov/wlr/lands/weeds/pdf/sulfur_cinquefoil-control.pdf