''Asclepias viridis'' is a species of

milkweed ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans ...

, a plant in the

dogbane family Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...

known by the common names green milkweed, green antelopehorn and spider milkweed. The Latin word ''viridis'' means green. The plant is native to the

midwestern The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...

, south central and

southeastern United States The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geographical region of the United States. It is located broadly on the eastern portion of the southern United States and the southern por ...

, as well as to the southeastern portion of the

western United States The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the Wes ...

. ''A. viridis'' is a perennial forb with alternately arranged leaves. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is an

umbel In botany, an umbel is an inflorescence that consists of a number of short flower stalks (called pedicels) that spread from a common point, somewhat like umbrella ribs. The word was coined in botanical usage in the 1590s, from Latin ''umbella'' "p ...

of white flowers with purplish centers. Its root system is a taproot, like that of butterfly weed (''A. tuberosa''). ''A. viridis'' grows on many types of soil. It is common in

overgrazed Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature rese ...

pasture land and roadsides.

Ecology

Like some other milkweed species, ''A. viridis'' is a host plant for the monarch butterfly (''Danaus plexippus'').Van Hook, T. and M. P. Zalucki. (1991)
Oviposition by ''Danaus plexippus'' (Nymphalidae: Danainae) on ''Asclepias viridis'' in northern Florida.
''Journal of the Lepidopterists' Society'' 45(3) 215-21.

Monarch Watch Monarch Watch is a volunteer-based citizen science organization that tracks the fall migration of the monarch butterfly. It is self-described as "a nonprofit education, conservation, and research program based at the University of Kansas that foc ...

provides information on rearing monarchs and their host plants. Efforts to restore falling monarch butterfly populations by establishing butterfly gardens and monarch migratory "waystations" require particular attention to the target species' food preferences and population cycles, as well to the conditions needed to propagate and maintain their food plants. For example, where it grows in the southern Great Plains and in the western United States, monarchs reproduce on ''A. viridis'', especially when its foliage is soft and fresh. Because monarch reproduction peaks in those areas in late summer and early fall when scenescent milkweed foliage is old and tough, ''A. viridis'' needs to be mowed or cut back in July to assure that it will be regrowing rapidly when monarch reproduction reaches its peak. ''A. virdis'' is one of the first milkweeds to bloom in the Ohio River Valley (May to June). In that area, monarch butterfly and milkweed tussock moth (''Euchaetes egle'') caterpillars are seldom found on the plant as it sheds its leaves and becomes dormant in late June to early July before the two

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

species arrive.

Cultivation

The plant is difficult to cultivate and does not grow well in containers. The seeds of some milkweeds need periods of cold treatment (

cold stratification In horticulture, stratification is a process of treating seeds to simulate natural conditions that the seeds must experience before germination can occur. Many seed species have an embryonic dormancy phase, and generally will not sprout until this ...

) before they will germinate. To protect seeds from washing away during heavy rains and from seed–eating birds, one can cover the seeds with a light fabric or with an layer of straw mulch. However, mulch acts as an insulator. Thicker layers of mulch can prevent seeds from germinating if they prevent soil temperatures from rising enough when winter ends. Further, few

seedling A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embry ...

s can push through a thick layer of mulch.

References

External links

* * {{Taxonbar, from=Q4803921 viridis Flora of Alabama Flora of Florida