WSU Extension

Hortsense

Weeds
 
Annual bluegrass 
Barnyardgrass 
Bentgrass, creeping 
Bermudagrass 
Bittercress (Shotweed, Hairy bittercress) 
Bittersweet nightshade (European bittersweet) 
Black medic 
Blackberry (Himalayan, Evergreen, Pacific) 
Blue mustard (Purple mustard, Tenella mustard) 
Brackenfern, western 
Buffalobur 
Bull thistle 
Buttercup, creeping 
Canada thistle 
Catchweed bedstraw (Cleavers) 
Catsear, common (False dandelion) 
Chickweed, common and mouseear 
Clover 
Comfrey 
Crabgrass 
Dandelion 
Dock (Curly, Broadleaf) 
Dodder 
Downy brome (Cheatgrass, Downy chess) 
Dwarf mistletoes 
English daisy (Lawn daisy) 
English ivy 
Field bindweed (Wild morningglory) 
Field pennycress (Fanweed) 
Flixweed 
Foxtail (Green, Yellow, Bristly) 
Garden loosestrife 
Giant hogweed 
Goldenrods 
Groundsel, common 
Hawkweeds 
Hedge bindweed 
Henbit 
Herb Robert (Robert geranium, stinky Bob) 
Horsetails (Scouringrush) 
Horseweed (Marestail) 
Knapweeds 
Knotweeds (Bohemian, Giant, Japanese, Himalayan) 
Kochia 
Lambsquarters, common 
Liverworts 
Mallow, common (Cheeseweed, Buttonweed) 
Nightshades 
Oxalis (Creeping woodsorrel) 
Parrotfeather and Eurasian watermilfoil 
Pineappleweed 
Plantain (Broadleaf, Buckhorn) 
Poison hemlock 
Poison ivy and Poison oak 
Prickly lettuce (China lettuce) 
Prostrate knotweed 
Puncturevine (Tackweed, Goathead) 
Purple deadnettle (Red deadnettle) 
Purple loosestrife (Purple lythrum) 
Purslane, common 
Quackgrass 
Red sorrel (Sheep sorrel) 
Redroot pigweed (Rough pigweed) 
Redstem filaree (Stork's bill, Crane's bill) 
Reed canarygrass 
Russian thistle (Tumbleweed) 
Ryegrass, annual (Italian ryegrass) 
Salsify (Goatsbeard) 
Scotch broom 
Shepherd's-purse 
Smartweeds 
Sowthistle, annual and perennial 
Speedwells 
Spurges (Prostrate spurges) 
St. Johnswort, common (Goatweed, Klamathweed) 
Stinging nettle 
Tansy ragwort 
Tumblemustard (Jim Hill mustard) 
Velvetgrass (Common velvetgrass) 
Velvetleaf 
Water primrose 
Waterhemlock, western 
Yellow nutsedge 



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Caption: Comfrey bell-shaped flowers
Photo by: T.W. Miller
  
Weeds : Comfrey : Symphytum officinale
(revision date: 6/9/2014)

Family: Boraginaceae
Cycle: Perennial
Plant Type: Broadleaf

Biology
Comfrey has clump-forming perennial roots with brown to black bark. The roots are thick and penetrate deep in the soil, making comfrey difficult to eradicate once established. Plants are from one to three feet tall. Leaves are thick and broad, growing primarily from the base of the plant, and are roughly hairy on both upper and lower surfaces. Lower leaves may exceed eight inches in length. Flowering stems rise from the center portion of the plant and bear somewhat inconspicuous dull bluish-pink (sometimes white, cream-colored, or purplish), bell-shaped nodding flowers. Fruits consist of four glossy, brownish-black nutlets or seeds joined at the base. SPECIAL INFORMATION: Although comfrey has a long history of both food and medicinal use, it should not be taken internally. The plant contains a toxic substance which can cause chronic liver damage. Comfrey may be confused with purple foxglove (Digitalis purpurea), which is toxic.
Habitat
Comfrey is most often found spreading from sites where it was introduced as an ornamental or herb. It prefers moist, rich soils and can be found in meadows and waste places.

Management Options

Non-Chemical Management
None recommended
Select non-chemical management options as your first choice!

Chemical Management

Apply according to label directions. Not a problem in established turf areas. Glyphosate products should be applied as spot treatments only! NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas
  • glyphosate
Turf areas
    Bare ground areas
    • glyphosate
    Images

    + Show larger images

     
    Caption: Comfrey bell-shaped flowers
    Photo by: T.W. Miller
    Caption: Comfrey leaf
    Photo by: T.W. Miller
    Caption: Comfrey bell-shaped flowers
    Photo by: T.W. Miller
    Caption: Comfrey in waste area
    Photo by: T.W. Miller
    Caption: Comfrey hairy stem
    Photo by: T.W. Miller