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SEASONAL IDENTIFICATION
POISON HEMLOCK (Conium maculatum)
FALL
-
SPRING
EARLY
SUMMER
SUMMER
LATE
SPRING
-
SUMMER
SUMMER
FALL
&
WINTER
Seedlings and rosettes can be found in large patches
in spring or fall. Note the thick tap root and that poison
hemlock is hairless.
Poison hemlock flowers develop as rounded clusters in an
umbrella formation. Poison hemlock is commonly found on
slopes and other unmowed areas in early summer.
From a distance, colonies in seed appear yellow. As mature
poison hemlock plants begin to fade away for the year, the
entire plant turns yellow.
Stems are smooth and hollow with purple splotches. The
divided fern-like leaf is glossy and more broad than wild
carrot leaves.
After flowering, seeds rapidly develop, but not all at once.
Seeds are yellowish green, small, and round with vertical
ridges.
As plants die, they turn rust colored and will drop seeds
into the fall. Zigzag stems will persist overwinter. Check for
seedlings in these areas to plan spring applications.
