May

Purple to Pink Flowers

Tamarisk

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  • A perennial weed that spreads by root and seed
  • Grows as a shrub or deciduous tree; may be 5 to 20 feet tall
  • Produces delicate pink to white flowers during spring or summer
  • Leaves are tiny and resemble cedar leaves
  • Grows in dense colonies along riverbanks, and ditches; a mature tree may use as much as 200 gallons per day
  • Weeds will resprout vigorously if cut or burned
  • Chemical controls are needed

Yellow Flowers

Flixweed

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  • Winter annual that blooms early in spring.
  • Grows 8-24 inches tall.
  • Plants are bushy.
  • Leaves are feathery and deeply lobed.
  • Small, four-petaled yellow flowers.
  • Common in disturbed sites.
  • Remove prior to seed set by pulling or hoeing.

Bur Buttercup

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  • Annual that hugs the ground (2-5 inches tall).
  • Grayish-green leaves are deeply lobed and finger-like.
  • Five-petaled, small yellow flower.
  • Sharp burr-like seed (up to 1 inch long).
  • Remove prior to seed set by pulling, hoeing or mowing.
  • Highly toxic to sheep.

White Flowers

Hoary Cress

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  • A perennial that spreads by roots and seeds
  • Grows up to 2 feet tall
  • Produces white flower clusters with flat tops in May
  • Leaves are lance-shaped and bluish-green
  • Grows in meadows, fields, roadsides, ditches, streams, and rangelands as well as garden sites
  • Mow two to three times per year at the bud stage to slow spread
  • Do NOT pull, as plants will grow from root fragments
  • Chemical controls are available

Grasses

Cheatgrass

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  • Winter annual that grows 4 to 30 inches tall
  • Seed stem is skinny and droops like a shepherd’s crook
  • Green in spring, fades to reddish-purple by early summer, and then tan by mid- to late summer
  • Acute fire danger
  • Remove prior to seed set by pulling, hoeing or mowing
  • Common in disturbed sites
  • Herbicides are available for larger infestations

Foxtails

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  • A variety of common species are included in this category
  • Some are perennial, some are annual
  • All are between 1 and 2 feet tall
  • Some are bunchgrasses, some are not
  • They are green and bushy early in the season but become dry and brittle in mid- to late-summer
  • On some species, individual seeds break off and carry easily, sticking in socks and posing a danger to pets
  • Remove prior to seed set by pulling or hoeing
  • Mowing may result in prostrate growth with renewed flowering
  • Herbicides are available