Garlic Mustard

• Invasive
• Biennial, herbaceous
• Shaded, wooded areas
• White flowers in May

Identification:  Dark green, heart-shaped leaves, with scalloped edges, on a single weak stem.  Look for a distinct “S” shaped curve at the base of the stem.  The plant can grow to four feet tall its second year and will flower in May, with tiny white, four-petaled blooms.  The foliage, when crushed, produces a garlic-like smell.  Garlic mustard is capable of out competing native plants and dominating the area.

Garlic mustard infestations should be reported to the Minnesota DNR.  (link: https://www.dnr.state.mn.us/invasives/terrestrial/report.html)

Control Options:  Garlic mustard is difficult to eradicate, and control measures will need to be repeated multiple times, often over several years.  Early detection and removal, before the plant flowers and seeds, is key to success.

1. Pull by hand, ensuring the entire root is removed.  Do not leave the weed on the ground.  Bag and dispose of in the garbage.  Do not compost.
2. Mowing low to the ground, ONLY before the plant flowers and seeds.
3. Controlled burns may be effective.  Burn after garlic mustard emerges, but prior to emergence of desirable plants.
4. Herbicide treatments may be used when the plant is in early flowering stage (early spring) and should be followed up by removing the plants, bagging, and disposing of them.

Common Buckthorn (Rhamnus cathartica)

• Restricted, noxious weed/shrub
• Well-drained soils, tolerates shade, but prefers sun

Identification:  Buckthorn is an understory shrub that can get up to 25 feet high.  It has shiny gray to brown, flaky bark and an orange sapwood.  The dark green leaves are elliptic-shaped.  Look for veins curving to the leaf tips for identification.  Twigs often terminate with a thorn-like spine between dark, scale covered buds.  Buckthorn has male and female plants, with only the female producing fruit and seeds.

Control Options: 

1. Target the female plants first and pull by hand or mechanically.  Disposal is best done by burning the plant.
2. Controlled burns can be helpful but will likely need to be repeated.
3. Cutting of stems must be followed with the application of an herbicide, to prevent resprouting

Glossy Buckthorn  (Frangula alnus)

• Restricted, noxious weed/shrub
• Well-drained soils, tolerates shade, but prefers sun

Identification:  Understory shrub that can get up to 20 feet high.  It has shiny gray to brown, flaky bark and an orange/pink/yellow sapwood.  The shiny dark green leaves are elliptic-shaped and slightly hairy on the underside.  No thorns, spines, or bud scales.  Red to dark purple berries.  The plant is monoecious, therefore, all plants can fruit.

Control Options:

1. Pull by hand or mechanically.  Disposal is best done by burning the plant.
2. Controlled burns can be helpful but will likely need to be repeated.
3. Cutting of stems must be followed with the application of an herbicide, to prevent resprouting.

Creeping Charlie

• Invasive
• Perennial, evergreen, herbaceous
• Semi-shaded to shaded moist soils
• Common, likes disturbed and degraded spaces.

Identification:  Square stems, toothed, heart or round shaped leaves that grow opposite each other.  Bright green in color with blue to purple flowers.

Control Options: 

1. Pull by hand, ensuring every living part of the plant is removed, including roots.
2. Fill spaces with grass or other desirable plants, to keep Creeping Charlie at bay.
3. Apply a broadleaf herbicide.  More than one application will likely be needed.  Apply in the spring when the flowers bloom and again in summer.

Common Nettle (Urtica dioica), aka Stinging Nettles

• Invasive
• Perennial, herbaceous
• Sun to shaded damp, fertile soils

Identification:  Saw tooth leaves, on opposite sides of a stem.  Leaves and stem are covered with plant hairs, some that sting.  The roots are yellow creeping rhizomes.  The flowers are tiny, white, or green.

The stinging hairs called trichomes , act like hypodermic needles, injecting histamine and other chemicals and producing a stinging sensation upon contact.

Nettles are commonly used in herbal medicines, as food, in tea, as a textile raw material, and sometimes in cosmetics.

Control Options: 

1. Pull by hand, ensuring every living part of the plant is removed, including roots.  Wear gloves, long sleeves, and long pants to protect from stinging.
2. Close mowing or weed whacking may retard growth.
3. Apply a post-emergence herbicide.

Lambsquarter (Chenopodium album) aka Wild Spinach

• Annual, herbaceous
• Sun to shade

Identification:  Leaves are light green on top and whitish underneath and shaped like an elongated triangle.  The leaves often have waxy crystals that rub off.  The small, green flowers cluster together.  The plant can get three feet or taller, with a hexagon shaped stem.

Lambsquarter will grow and spread rapidly, given the chance.  While some consider it an undesirable plant, Lambsquarter does have medicinal uses, and all parts of the plant are edible.

Control Options: 

1. Lambsquarter germinates by seed, so pulling by hand, before the plant matures and sets seed is key.
2. Close mowing or weed whacking may retard growth.
3. Apply a pre-emergent herbicide to prevent seed germination and post-emergent herbicide to kill weeds after germination.

Musk Thistle (Carduus nutans)

• Invasive
• Biennial, herbaceous

Identification:  Dark green leaves alternate, are lobed and prickly with a waxy surface.  The plants bloom spring to early fall in disk-shaped flower heads with large bracts of hundreds of tiny purple flowers.

Control Options: 

1. Mowing or hand cutting before the flowers emerge.
2. Dig out the roots at least two inches below the ground surface.
3. Plants with flower stalks are more difficult to kill than the rosettes. Rosettes need to be treated when they are actively growing, in the fall or spring.

Bindweed (Convolvulus) aka Creeping Jenny

• Invasive
• Perennial, herbaceous

Identification:   Bindweed has thin vines that wrap themselves tightly around any upward object.   They have medium green arrowhead shaped leaves and will eventually bloom with trumpet shaped flowers.

Control Options:  Several attempts of any control method will be required.

1. Repeat pruning down to the soil level is more effective than pulling.
2. Aggressive planting of desirable plants.
3. Non-selective herbicides