Spring Weeds

A thistle plant with spiky, serrated leaves growing on the ground.

Spring has sprung! That means grasses, flowers, and weeds will start popping soon. While we all look forward to green grass and spring flowers,

We must be cognizant of the noxious (and obnoxious) weeds that break ground first and outcompete native vegetation for resources.

It is because many of the early sprouting weeds are annuals or biennials that they start growing before most perennials break senescence. Many other biennials overwinter as rosettes.

As annuals and biennials, many of these weeds can be hand pulled (especially when young and the ground is soft). Others can be dug up, but some will need herbicide.

Contact Grand County Natural Resources (970.887.0745) or Summit County Weed Department (970.688.4218) for specific herbicide recommendations or check out the herbicide sheet below.

CSU Chemical Recommendations_ListsA&B

The early sprouting noxious weeds!

Black henbane
Cheatgrass/Drowy Brome (NOTE: Milestone and Telar will not work on cheatgrass as it is a grass not a forb)
Hoary Cress/Whitetop
Scentless chamomile
Houndstongue rosettes
Musk thistle & bull thistle rosettes
Mullein rosettes
Knapweeds: Diffuse, Russian, Spotted

Other early sprouting obnoxious weeds (not listed as noxious but worthy of control)

Yellow Sweetclover
Various annual mustards – all mustards have 4 petals

A green thistle plant growing in rocky soil.

Black Henbane (B)

In the early season (annual), or first year of growth (biennial), the plant is represented by a rosette. The margins are entire to slightly wavy. The veins are prominent and depressed on the upper surface. Rosette: Rosette leaves are soft, alternate and have leaf stalks nearly as long as the leaf blades.

A lush, green plant with delicate, feathery foliage, displayed on a dark blue background.

Chamomile Daisies (B)

White daisy flowers with ferny or feathery leaves. Very shallow root system makes it easy to hand pull.

Wild grasses with drooping seed heads growing in sandy soil.

Cheatgrass/Downy Brome (C)

Cheatgrass greens up before other grasses and is very easy to pull being that it is an annual. Other grasses won't be as easy to pull.

A green plant with fuzzy leaves grows low to the ground, surrounded by grass and small yellow flowers.

Common Mullein (C)

The first year of the plant it produces a basal rosette. Basal rosettes can grow over 30 inches in diameter. The leaves are light-green in color and are covered in fine soft hairs. The woolly leaves are alternate and overlapping each other and can grow over a foot long.

A small green seedling emerging from the soil, labeled "seedling."

Hoary Cress/Whitetop (B)

Seedlings overwinter as rosettes and emerge in early spring with stems emerging from the center of each rosette in late April. All leaves have a covering of soft white hairs. Hoary cress flowers from May to June and plants set seed by mid-summer. The hoary cress root system is very extensive.

A small green plant with large leaves growing on rocky ground.

Houndstongue (B)

Leaves are rough and hairy. They are 4-12 inches long and narrow. They are said to look like a dog/hound’s tongue, where it gets its name. Hairs are long, soft, and white. Leaves often appear dusty and insect-ridden.

A green weed with elongated leaves growing on dry soil.

Knapweeds

Diffuse and Spotted Knapweeds are biennials or short-lived perennials and will have rosettes and lower shoot leaves are deeply divided and covered with short hairs.

The Thistles

During early spring, you are looking for thistle rosettes from biennial Musk and Bull Thistles. You won't see flowers in early spring. Get them before flowers bloom.

Yellow wildflowers with green leaves growing outdoors.

Yellow Sweetclover

Yellow sweetclover is the tall plant you see growing throughout the county that has trifoliate leaves (3 leaflets) and racemes of small yellow flowers…

We must be cognizant of the noxious (and obnoxious) weeds that break ground first and outcompete native vegetation for resources.

CSU Chemical Recommendations_ListsA&B

The early sprouting noxious weeds!

Other early sprouting obnoxious weeds (not listed as noxious but worthy of control)

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