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Number 2, 1999
Bulb-Forming Weeds in Turf
Star-of-Bethlehem and wild garlic are two bulb forming weeds that
commonly invade turf areas in the early spring growing period.
STAR OF-BETHLEHEM (Ornithogalum umbellatum), also
known as summer snow-flake and star-flower, is a common early-spring
weed problem that occurs throughout Illinois. A member of the
Lily Family, star-of-Bethlehem is a perennial, bulb-former that
has escaped old ornamental beds to invade lawns and also landscape
and waste areas. Seed propagation is rare; it is primarily spread
by small bulbs or bulblets. It is reported that all parts of star-of-Bethlehem
are poisonous.
Description:
The oval bulbs are 1/2"- to 1-1/2" long with fibrous
roots at the base. Commonly, the bulbs wili increase to form clumps.
In early spring, tufts of fleshy, dark green linear leaves, approximately
4-12" long and up to 1/4" wide, emerge from the ground.
Each leaf has a lightcolored midrib. Shortly after the leaves
emerge, branched, leafless flower stalks (scapes), similar in
length to the leaves, appear. At the end of each branched stalk
is a star-shaped flower appearing to have six white petals, each
with a green stripe on the underside.
Control:
Control of star-of-Bethlehem is difficult; it emerges, flowers,
and dies to the ground early in the spring growing period. A perusal
of weed-control literature failed to identify any labelled chemical
control options. Digging, drying, and discarding the bulbs is
most commonly recommended controi practice.
SPRING BEAUTY (Claytonia virginica) is occasionally
mistaken for star-of-Bethlehem. Spring beauty is a member of the
Purslane Family and is a commonly found Illinois native. It emerges
from fleshy, tuberous roots and produces elongated leaves approximately
6" in length and 1/2" wide. Individual flowers of spring
beauty have five petals (star-of-Bethlem flowers have six) and
are white tinged with pink, occur in branched inflorescences at
the ends of flowering stalks, and usually bloom during March and
April. Spring beauty is often found in moist woods or shaded areas.
WILD GARLIC (Allium vineale), like star-of-Bethlehem,
is a cool season, bulb-forming perennial member of the Lily Family
that commonly reproduces by aerial and underground bulbets. Reproduction
by seed in northern states is uncommon. A strong odor of garlic
or onion is produced by all plant parts when smashed. Wild garlic
is commonly found in fertile, poorly drained, fine-textured soils
and thin turf areas.
Description:
Beginning growth in early spring, the leaves of wild garlic develop
from the bulbs into upright, grass-like plants. Stems can grow
to more than 3 feet. The leaves of wild garlic are 2-ranked, slender,
hollow, nearly round; and attached halfway down on waxy stem.
The inflorescence is an umbel, 1 to 2 inch diameter. The flowers
are small, greenish-white, and found on stems above the aerial
bulblets. Flowering occurs during May and June. Less common is
wild onion (Allium canadense). Wild onion appears and smells similar
to wild garlic, but has solid leaves.
Control:
To control without chemicals, maintain turf density and health
through proper culture. Mow frequently and mechanically remove
all portions of plants. Apply ester formulations of postemergence
broadleaf herbicides containing combinations of 2,4-D, MCPP, MCPA,
dicamba, triclopyr, or clopyralid during early to mid spring when
weeds are actively growing.
(Tom Voigt, Bruce Spangenberg, Bruce Branham, and
Tom Fermanian)
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