Weed Control

Absinthe

ABSINTHE
(Absinth, madderwort, warmat, varmit, wormwood)

Habitat: Roadsides, waste places, farmyards, pastures, and cropland.

Description: Absinthe is a perennial that spreads by seed. The stems are .6 to 1.2 meters high, covered with fine hairs, grooved and woody at the base. Leaves are 5 – 10 cm long, alternate, covered with fine hairs, greenish with narrow/blunt segments. They have a small flower heads that are 5 mm across. They are drooping with numberous yellow or purple flowers. They flower from late July to September. Seeds are small, broader at the tip than the base, finely streaked, and brownish in colour.

Control Practices:

1. Cultivation is satisfactory where it can be done. Tillage must be done often enough to keep the plant weakened.

2. Seed early the year after cultivation to a competitive crop such as barley and rework the land after the harvest.

3. Good competition from strong stands of crop or grass will choke out the weed in most cases.

4. Chemical control is also an option.

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Scentless Chamomile

Scentless Chamomile
(False chamomile)

Habitat: Pastures, hayfields, cultivated fields, roadsides, and waste places.

Description: Scentless chamomile is an annual, biennial or short-lived perennial. The stems are erect, hairless and branch 20 – 74 cm high. THe leaves alternate and are finely dissected. Flowers are borne at the end of the branced stem. They are white with yellow centres with numberous flowers on each plant. Seeds are dark brown and groved and possess some dormancy. The plant germinates readily in the spring and fall. It has a dense fibrous root system which spreads rapidly during wet periods.

Control Practices:

1. Frequent shallow tillage in fall and spring will help in the destruction of seedlings. A cultivator with mounted harrows has been the most effective in killing the seedlings. If the soil is wet, many plants will re-establish.

2. Seeding to bromegrass for several years will reduce the infestation.

3. Mowing must be done early to prevent seed production and at least two mowings would be necessary in most years.

4. Chemical control is also an option.

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Perennial Sowthistle

PERENNIAL SOWTHISTLE

(Creeping sow-thistle, field sow-thistle, field milk thistle)

Habitat: Cultivated fields, meadows and roadsides

Description: Perennial Sowthistle is a creeping perennial with an extensive horizontal root system. It is reproduced by seeds and underground roots. The roots penetrate to a depth of 1.5 – 3 meters. The stem, which can grow up to 1.2 meters, is hollow, smooth and branches at the top. The plant also contains a milky substance inside the stem. The leaves alternate with a slightly toothed edge. Lower leaves have deep cut, backward pointing lobes. Leaves are approximately 15 – 30 cm long with upper leaves being smaller. The flowers are yellow in color; almost like a dandelion. They are 1.3 – 5 cm across. Seeds are small, brown, ridged and crowned with a tuft of fine hairs.

Control Practices: Tillage is the most effective way to control Perennial Sowthistle because it starves the root system. Start tillage as soon as possible after harvest, preferably with a cultivator. The next spring on of the following should be completed:

1. Start tillage early in spring and continue until freeze-up. Green growth should not remain above ground for more than a week.

2. Start tillage when the buds are in their early stage as this is when the plant is the weakest. Continue tillage until freeze-up.

3. Summerfallow until mid July to control other weeds. Then leave the Prennial Sowthistle undistrubed. When it reaches the early bud stage is should be sprayed with the appropiate chemical.

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