3
The Most Invasive
Non-Native Weeds
Garlic Mustard (
Alliaria
petiolata, A. officinalis
), a white-
flowered biennial with rough,
scalloped leaves (kidney, heart- or
arrow-shaped), recognizable by
the smell of garlic and taste of
mustard when its leaves are
crushed.
Control: Pull before it flowers in
spring (10) removing crown and
roots. Tamp down soil afterwards.
Once it has flowered, cut (2),
being careful not to scatter seed,
then bag and burn or seed to the
landfill. (11) may be appropriate in
some settings.
Japanese or Vietnamese Stilt
Grass, Eulalia (
Microstegium
vimineum
) can be identified by its
lime-green color and a line of
silvery hairs down the middle of
the 2-3" long blade. It tolerates
sun or dense shade and quickly
invades areas left bare or
disturbed by tilling or flooding.
Control: Easily pulled in early to
mid-summer (1) – be sure to pull
before it goes to seed. If seeds
have formed, bag and burn or send
to landfill. Mowing weekly, or when
it has just begun to flower may
Bush Honeysuckles (
Lonicera
spp.
), including Belle, Amur,
Morrow’s and Tatarian
honeysuckle. (In our region,
assume that any honeysuckle is
exotic unless it is a scarlet-
flowered vine.)
Bush honeysuckles create
denser shade than native shrubs,
reducing plant diversity and
eliminating nest sites for many
forest interior species.
Control: (2) on ornamentals; (1);
on shady sites only, brush cut in
early spring and again in early fall
(3); (4) during the growing
season; (7); or (10) late in the
growing season.
Other Ornamental Shrubs
Japanese Spiraea (
Spiraea
japonica
). Control: (1); (2); (3),
(7), (10), or (11).
Privet (all Ligustrum species).
Control: (1); (7) or (10); or trim off
all flowers. Do not cut back or
mow.
Burning Bush, Winged
Euonymus, Winged Wahoo,
(
Euonymus alatus
), identified by
wide, corky wings on the branches.
There is another species called
Burning bush,
E. atropurpureus,
which is indigenous to the
Appalachians, and a piedmont
euonymus called Strawberry bush
(
E. americanus
).
Control: (1); (7) or (10); or trim
off all flowers.
Japanese Barberry (
Berberis
thunbergii
), red and green
varieties.
Control: (1); (7) or (10); or trim
off all flowers.
prevent it from setting seed (3).
Use glyphosate (11) or herbicidal
soap (less effective) on large
infestations. Follow-up with (5) in
spring.
Mile-a-minute Vine, Devil’s Tail
Tearthumb (
Polygonum
perfolatum
), a rapidly growing
annual vine with triangular leaves,
barbed stems, and turquoise
berries in August which are spread
by birds. It quickly covers and
shades out herbaceous plants.
Control: same as for stilt grass.
Japanese Perilla, Beefsteak
Plant (
Perilla frutescens
). Sold as
a salad plant, this member of the
mint family is extremely invasive by
wind-borne seeds. Recognize it by
the odd odor, supposedly like raw
beef, when you rub it.
Control: (1); (2); (10) or (11).
Spotted Knapweed (
Centaurea
maculosa
) a biennial with thistle-
like flowers.
Canada Thistle, Bull Thistle
(
Cirsium arvense, C. Vulgare
).
Exotic thistles are far more
common than native ones. If you
cannot identify the species, it is
Garlic Mustard
