Tag Archives | Weed-of-the-Month

Knotweed

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 hardy, […]

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puncturevine-slider

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 […]

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Phslider

June’s Weed of the Month: Policeman’s Helmet

Policeman’s helmet (Impatiens glandulifera) is an invasive weed that grows in ditches, wetlands, and along waterways. Native to India, this fast-growing annual was introduced as an ornamental plant due to its impressive growth and the showy purple, pink, or white blooms. Since introduction, it has escaped cultivation to become the dominant riparian vegetation in many […]

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Orange hawkweed in bloom

May’s Weed of the Month: Orange Hawkweed

Orange hawkweed (Hieracium aurantiacum) is a relatively new invasive weed in Clackamas County and we are working 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 roadsides, meadows, pastures, hayfields, and disturbed sites.  […]

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garlicmustardslider

April’s Weed of the Month: Garlic Mustard

Garlic mustard (Alliaria petiolata) is an increasingly invasive weed in our community.  Native to central and western Europe, this fast-growing plant commonly invades sites such as parks, trails, roadsides, and streamsides. April is a great time to manage this important invasive weed on your property. Sometimes referred to as Jack-by-the-hedge, garlic mustard is easily identified […]

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Canada-thistle-slider

March’s Weed of the Month: Canada thistle

Canada thistle (Cirsium arvense) is a widespread invasive weed found in all parts of Clackamas County.  Unlike the many native thistles found in Oregon, Canada thistle can quickly overrun an area and displace native plants, reduce agricultural yield, and create problems for grazing animals when they infest a field or pasture. They also cost a […]

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ivy-slider

January’s Weed of the Month: English Ivy

English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, and provides a “no-mow,” evergreen ground cover — are the things that […]

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WeedWise Program