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University
of Rhode Island GreenShare Factsheets
Dandelions
The
common dandelion, Taraxacum officinale Weber, sometimes
known as Lions-tooth, Blow-ball or Cankerwort, is native to Eurasia,
but has been naturalized throughout most of the temperate United
States. The
dandelion is a perennial with a thick fleshy taproot. It spreads
by seeds and by new shoots from roots or root segments. It flowers
from early spring to late fall. Seedlings may occur throughout the
spring and summer and are often abundant in the fall. Common
dandelion is the most common broadleaf weed in many lawns. It is
found in virtually every kind of habitat, from openings in deep
woods to cultivated fields, from rocky hillsides to fertile gardens
and lawns. The
dandelion has a thick fleshy taproot with many-branched crowns and
milky juice. Stem is very short and wholly underground, producing
leaves at the ground surface. Leaves are simple, 3 to 10 inches
long, and contain a milky juice. Leaves vary in shape, from lobeless
or entire to deeply cut lobes. Flowerheads are golden-yellow and
1-2 inches in diameter, with yellow ray flowers, borned on a long,
hollow stalk. Achenes are yellowish-brown with 5 to 8 ribs on each
side and minute curved spines on the rib margins of the upper half
of the seed. Seeds are tannish, about 3/16 inch long, elongated,
with a slender tip bearing a tuft of hairs that are easily broken
off. Cultural:
Maintaining a dense, healthy, vigorous lawn is the best method
of controlling many turf weeds. The use of an adapted species of
grass, adequate fertilization, proper mowing and irrigation practices
and insect and disease control is the best way to minimize weed
problems. Low nitrogen fertilization will encourage weeds due to
less competition from desirable species. Mowing as soon as the first
flowerheads appear can reduce further infestations. Chemical:
Dandelions can be controlled by herbicides as well, if necessary.
Herbicides may be applied to dandelions in spring or fall, providing
that the dandelion is actively growing. Early fall may be the best
time to treat dandelions. The lawn should not be mowed for two or
three days before and after herbicide application. The treatment
application should be done at a time when there is not rainfall
for at least 24 hours. Adapted
from Prasanta C. Bhowmik, University of Massachusetts Cooperative
Extension, 2001
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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