Category: Weed War

Native Grasses

If you’re new to Colorado and the inter-mountain West, and you’re longing for those lush, green lawns that are so plentiful east of the Mississippi, we’ve got news for you. Much of Colorado is High Plains and relatively arid. What doesn’t fit that description is mountainous, with lots of snow in the winter and spring, monsoonal storms in the summer, and drought in the fall. Turf-style lawns, such as Kentucky Bluegrass, just don’t cut it here. A water-wise investment that looks as beautiful as turf can be had, according to the Denver Post: Continue reading “Native Grasses”

Field Bindweed (Convolvulus arvensis)

Field bindweed is a List C vining perennial in the morning glory family (Convolvulaceae). Known to be in North America since the 1700s and in Colorado since 1872, it was introduced as a contaminant of seed. It can now be found in all 50 states.

Field bindweed is native to Eurasia and Asia and naturalized in many other parts of the world. It has a thick taproot that can grow to 20-30 feet deep, with multiple horizontal rhizomes that have buds to form new plants. Plants can easily regrow from root fragments.

The root mass can reach 2.5 to 5 tons per acre. The trumpet shaped flowers form in the leaf axis. Flowers form from late spring until frost. The 1-inch-wide flowers are white to pink and have two small bracts that form .5 to 2 inches below the flower. Each flower produces a roundish fruit that contains two to four seeds. The seeds can stay viable in the soil for 20+ years.

Field bindweed stems are around five feet long. They are twisted and are either prostrate or can climb and cover other plants, fences, and structures. The 2-inch long and 1-inch-wide leaves are alternate, simple and arrow shaped, smaller towards the ends of the stems. A serious pest in wheat and bean crops, it also invades vineyards, orchards, degraded range lands, landscaped areas, and lawns. Field bindweed can harbor plant diseases (potato X disease, tomato spotted wilt, and vaccinium false bottom).

Control can be done using cultural techniques and/or systemic herbicides. It requires persistent efforts over multiple years. The bindweed gall mite, Aceria malherbae, has shown some good success in areas that are grazed or mowed.

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Weed War

Deer in a Canadian thistle thicket

Weeds are a growing concern in our neighborhood. Many homeowner associations and individuals informed C.A.R.E. that they felt overwhelmed by the numbers of weeds after last summer’s rains, particularly, the Bull, Canada and Musk thistles. Even thistle thickets like the one above can be overcome.Meadow following Canadian thistle removal Read how to achieve a thistle-free pasture that looks like this meadow.  Continue reading “Weed War”

Thistle Before and After/ Fall & Late Summer Information

BEFORE Deer in a Canadian thistle thicket

AFTERMeadow following Canadian thistle removal

Canada Thistle (Late Summer)

You might as well mow the area now (saving the step of cutting the seed heads only).  We can’t stress enough that if you will use a bag on your mower to collect all cuttings, you will greatly reduce the number of seeds left on the ground to germinate next year. Continue reading “Thistle Before and After/ Fall & Late Summer Information”

Dalmatian Toadflax

Dalmatian ToadflaxDALMATIAN TOADFLAX

Linaria dalmatica ssp. dalmatica
Figwort Family

Colorado Dept. of Agriculture Class B

Aliases: Balkan toadflax, broadleaf toadflax, wild snapdragon, smooth toadflax
Perennial: Forb
Flowers/Fruit: Seeds Mature July – September. (Oct. after the 1st year)
Flowers: Snapdragon type, bright yellow, tinged with orange,  1-1/2″ long spur. The upper lip is 2-lobed and the lower is 3-lobed.
Bloom: May – August Continue reading “Dalmatian Toadflax”

Diffuse Knapweed

Diffuse KnapweedDIFFUSE KNAPWEED

Centaurea diffusa Lam. Asteraceae (sunflower family)

Colorado Dept. of Agriculture Class B

List B Eradication Required

Aliases: Spreading Knapweed, tumble knapweed, white knapweed
Annual: (1 yr life cycle). Most commonly a short-lived perennial (survives the winter but doesn’t do well the 2nd yr.); occasionally a biennial (needs 2 yrs to complete its life cycle).

Continue reading “Diffuse Knapweed”