7 prolific weeds found in local yards and ways to control them

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March 4, 2022 4:07 p.m.

Shiny geranium

Don’t get this confused with our native geranium, this low-growing annual has shiny light green leaves, red stems and small dark pink flowers. It has a tendency to break off at the crown and re-sprout if not carefully removed. Hand pull before they go to seed. Remove as much root and stem as possible. Put all parts in a bag and toss in the trash. Visit the patches for a few years to dig any leftover plants that are missed the first time around.

Top view of a bittercress basal rosette with young green seed pods. — Hairy bittercress.

Hairy bittercress

This plant grows in a ground-hugging rosette with tiny round leaves and sends up white flowers on slender stems. They have shallow roots making it easy to pull, but make sure you pull them before they go to seed to keep it from spreading prolifically. One plant can produce hundreds to thousands of seeds within weeks and launch them several feet away.

Traveler's joy

This woody deciduous vine is a pro at blanketing its surrounding areas. Its leaves are compound and usually arranged with five heart-shaped leaflets. Its white flowers bloom in the summer followed by feathery seed heads. If the plant is established, cut the vine around waist height, remove all root material and dispose in the trash. If you wish to tackle an infestation, contact your local weed control program.

English ivy

Remove the berries of this evergreen vine before they ripen to prevent its spread by birds. It easily takes root, climbing up trees and buildings. Cut the vines around the trunk of the tree to kill the ivy in the upper branches. For patches on the ground, get some gardening scissors and start pulling and cutting. Gloves are recommended, as its sap can cause skin dermatitis. Bag the ivy and toss in the trash.

English holly

Commonly known for holiday décor, the berries of this broadleaf evergreen tree or shrub are toxic to humans. The plant sports dark green lobed and glossy leaves with spiny edges and can grow to 20 feet tall. It can spread via vegetative reproduction, when a new plant grows from a new stem of the parent plant. Hand pull or dig up small plants easily. Larger plants can be removed with a weed wrench. Toss the berries in the trash and the rest of the plant in the compost bin.

Canada thistle

This perennial quickly spreads through roots and seed. It features hairy stems and smooth leaves with wavy and spiny edges, and has purple or sometimes white flowers. Preventing establishment is most effective to control this species. You can get rid of thistle manually, by digging it up. Gloves are recommended, since it is prickly. It is important to remove the flowers, before it seeds.

Knotweed

This bamboo-like perennial spreads by rhizomes, having a deep root system that can sustain the plant. Targeting the root system is key to controlling knotweed. Digging is possible for small plants, but make sure you get all of the root material and dispose of it in the garbage. Contact your local weed control program to rid of bigger patches of knotweed.

Additional resources

For more information on these and other weeds, check out the 4-County Cooperative Weed Management Area.

Not sure whether something you want to plant may become a problem? The Portland Pland List provides extensive information on native and invasive plants in the area.

Need to talk with an expert? Contact your local soil and water conservation district.

Sign up for the Backyard Habitat Certification Program.