INVASIVE PLANTS - Technical Learning College

Redroot pigweed is an annual weed commonly found in waste areas and disturbed soils. It can
attain a 2-4 foot height. The lower stems are reddish in color. Flowers are small and green, in
bristly terminal and axillary clusters. A prolific seed producer, pigweed will produce up to 100,000
seeds per plant. Seedlings are easily pulled or hoed from the garden. Older plants are more
difficult to pull out and may scatter seeds in the process. Mulch will prevent seeds already in the
soil from germinating.
Control When found in the lawn, pigweed can be spot-treated with herbicides containing MCPP,
MCPA, and dicamba. In gardens, glyphosate (Round-up, Kleen-up) can be used, taking care not
to get any of the chemical on desired plants. Pre-emergents containing oryzalin, pendimethalin,
or trifluralin can be effective. When using a herbicide, be sure to read the label carefully and
follow directions closely.
Dandelion The Dandelion is a perennial with an extensive taproot. Its yellow flowers can
develop anytime between March and November and are followed by fluffy seed heads. More
prevalent under low turf density, dandelion growth can be inhibited by increasing the turf density.
Dandelions can be dug out with special tools, but any part of the root that is left is capable of
regenerating a plant.
Control A 2,4-D or 2,4-D combination herbicide is most effective and should be used in spring
and fall. Always read the label before applying any pesticide.
Curly dock is a perennial weed in the buckwheat family. Fairly pleasant tasting, the leaves are
very rich in vitamins, especially vitamins A and C, and can be eaten raw or cooked. The roasted
seed has been used as a coffee substitute. It is also a very important food plant for the caterpillars
of many butterflies. In the spring, basal leaves emerge from a stout taproot. These
elongated leaves have wavy margins, thus the name "curly" dock. In summer, the plant has
reddish, rigid stems, 2-4 feet tall. Flower stems have greenish flowers.
This is a tenacious perennial weed that is found in lawns throughout the United States. Its large
taproot grows deep into the soil, which enables it to thrive in times when grass may be suffering
from heat and lack of moisture. In fall, winged fruits form on the flowering stems that are reddishbrown
in color. Curly dock is not easily pulled because of the deep taproot, and portions of this
root left in the ground will regenerate.
Control Combination herbicides containing mecoprop, dicamba and 2,4-D are effective in the
control of Curly dock.
Quackgrass, a creeping perennial, is a very aggressive grass and is considered a noxious weed
in most states. It spreads by seeds and invasive rhizomes (underground stems). Its rhizomes are
yellow-white, with brown sections, and the ends are sharply pointed.
Control A few quackgrass plants can be spot-sprayed with glyphosate, or individual blades can
be painted with glyphosate. Note that glyphosate will kill any bluegrass it contacts. Repeat
applications to quackgrass will likely be needed. Renovate severely infested lawn areas. Spray
with glyphosate; repeat applications will likely be needed. When the quackgrass has been killed,
the areas may be re-sodded or re-seeded. Always read the label before applying any pesticide.
Broadleaf Plantain is a low growing perennial. It has broad leaves with prominent veins. The
leaves are arranged in a rosette and may smother lawn grass. The flowering spikes normally
grow taller than the foliage but may develop below mowing height. Vigorous, thick turfgrass is
less susceptible to invasion.
Control Triclopyr + 2,4-D or 2,4-D alone or 2,4-D combination herbicides should control plantain.
Always read the label before applying any pesticide.
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