Weed-Specific Removal

Weed-Specific Methods:

These Best Management Practices (BMPs) have been developed by Seattle Parks and are based on the experience of volunteers and restoration professionals. You feedback on these methods is essential!

English Ivy (Hedera helix)

Create tree "life-savers" by cutting vines at shoulder height, then again at the base of the tree, then grub out a radius of at least five feet away from the tree. Do not attempt to pull vines out of the tree, they will decompose eventually.
Remove ground patches of ivy by clipping edges of swaths and rolling into a mat.
Take care to cut around or gently lift ivy mat over existing native plants.
Clear ivy at least 10 feet beyond proposed planting area to create ivy-free buffer

Ivy roll

Himalayan Blackberry and Evergreen Blackberry (Rubus aremeniacus and R. lanciniatus)

Blackberry has thorns. Be sure to wear gloves!
Cut and grub root wads (may be necessary to repeat for 2-3 growing seasons before planting as this species is very vigorous and difficult to eradicate).
For sites ¼ to ½ acre, remove half of the infestation one year, half the next.
For sites greater than ½ acre, remove no more than ¼ of the infestation each year.

Cherry Laurel/English Holly

Small, young plants may be hand-pulled or weed-wrenched
Cut seed heads, place in plastic bag and dispose of in a landfill immediately.
Large plants require herbicide (Only to be preformed by Parks staff or contractors).

Scot’s Broom

Hand-pull small plants and weed-wrench or excavate larger plants when soil is moist in spring OR
Cut plants in early summer, just as flowering begins, then cut again at least once later in summer

Clematis or Old Man's Beard (Clematis vitalba)

Cut vine at the base in early summer before seed production and grub out root
Seedlings can be handpulled
Stems may be pulled in winter when brittle

Field Bindweed or Morning Glory (Convolvulus arvensis)

Hand pull at least three times per year; early growing season, mid-summer and late summer for at least three growing seasons
Remove all fragments from the site
Flag site and monitor

Hawthorne (Crataegus laevigata) - non-native

Cut to the ground repeatedly for at least three growing seasons
Mark stump and monitor

Bohemian Knotweed (Polygonum x bohemicum)

Chemical -Stem Injection (Only to be preformed by Parks staff or contractors)
Hand removal of knotweed is impractical and may exacerbate the problem
Grubbing may work for very small patches – all material must be bagged and disposed of in a landfill immediately.