Before and After: Blessed Milkthistle Management One Year Later
What a difference a year makes It was one year ago that we reported a large infestation of milkthistle (Silybum marianum) growing in a twenty-acre horse pasture outside of Wilsonville. At that time, the WeedWise program was approached by the resident for assistance in helping her to control the milkthistle. As a priority invasive weed […]
October’s Weed of the Month: Himalayan Blackberry
The Thorn in Our Side Himalayan blackberry (Rubus bifrons) tantalizes us with its sweet fruits in the summer and tortures us with its prickly vines all year long. Also known as Armenian Blackberry, this wide-spread and aggressive weed is native to Armenia and Northern Iran. It is considered an invasive species in many parts of […]
Plant Identification: What is that Weed?
Do you think you’ve found a noxious weed? Here is how you can get help to identify and report your find! One of the most important aspects in controlling invasive weeds is to verify the identification if invasive weeds before you work to control them. Knowing the difference between an aggressive weed and a common […]
September’s Weed of the Month: Knotweed
September is the Time to Control Japanese Knotweed Japanese knotweed (Fallopia japonica) has been called a “nightmare” and a “botanical bully,” and is one of the 100 worst global invaders. These characterizations give you a pretty good idea of just how unwelcome this invasive weed is in our community. Japanese knotweed is fast growing and […]
August’s Weed of the Month: Puncturevine
Puncturevine (Tribulus terrestris) is aptly named! This invasive weed has spiny seed heads that can easily puncture a bike tire, inflatable raft, animal paw, or footwear. Be on the lookout because it is beginning to make its way into Clackamas County from eastern and southern Oregon. Also known as “goathead”, puncturevine is native to southern […]
Tansy Ragwort Poisons Livestock and Neighborly Relationships!
Tansy ragwort has long tormented rural landowners who graze livestock. Horses and cows are especially susceptible to this poisonous weed. In open fields, grazing animals will generally avoid eating tansy ragwort, but in heavily infested pastures they may have few other options. Contaminated hay is particularly a problem because it becomes impossible for feeding animals […]
July’s Weed of the Month: Tansy Ragwort
Tansy ragwort (Senecio jacobaea) is an invasive weed with a long and deadly history in the Pacific Northwest. In Oregon, it is designated as a Class B invasive weed. It is believed to have been introduced here in the early 1900’s through ballast water from a ship. This plant in native to Europe and […]
June’s Weed of the Month: Policeman’s Helmet
Policeman’s helmet (Impatiens glandulifera) is an invasive weed which grows in ditches, wetlands, and along waterways. Native to India, this fast-growing annual was introduced as a ornamental plant due to its impressive growth and the showy purple, pink or white blooms. Since introduction, it has escaped cultivation to become the dominate riparian vegetation in many […]
The new thistle you don’t want on your property!
We have plenty of thistles growing in our area and landowners across the region are working hard to combat these prickly invaders. While most of the thistles growing in our area are invasive, some of them are actually native. Unfortunately, a recent discovery from eastern Oregon marks the addition of a new invasive thistle to […]
May’s Weed of the Month: Orange Hawkweed
Orange hawkweed (Hieracium aurantiacum) is a relatively new invasive weed in Clackamas County. With your help, our team plans to keep it from becoming a common problem for landowners! A member of the sunflower family, orange hawkweed is native to central and southern Europe and grows in open areas like gravel pits, roadsides, meadows, pastures, […]
