Poisonous/Cautions:
Milkweed
species are generally thought to be poisonous to livestock. Pub 505
suggests that there is some evidence to suggest that common
milkweed is toxic, and that other species are highly
toxic.
Distribution:
Common
milkweed occurs throughout Ontario in pastures, waste areas,
roadsides, and cultivated fields. Grows best in open areas. Swamp
milkweed occurs mostly in wet habitats of swamps and ditches. Green
milkweed is native to coarse soils. Whorled milkweed occurs in dry
open areas. Swamp and whorled milkweed relatively rare compared to
other milkweed species.
Growth
Habit:
Perennial
Method of
Propagation:
Seeds, Wind
blown, Roots/rhizome
Control:
Glyphosate
at medium to high rates (Roundup Ready crops) at bud to early bloom
stage, tolerant to 2,4-D, intermediate to dicamba. Listed on
Roundup label but not on 2,4-D or Banvel labels. Apply herbicide at
early bud (flowers mid summer) or in early fall. Repeated mowing at
21 day intervals can be an effective control. A single cutting will
stimulate the sprouting of underground root buds. Repeated cutting
prior to fruit (pod) formation will reduce root
reserves.
Other
Comments:
Host and
food source for Monarch butterfly.
