Short Green Milkweed (Asclepias viridiflora) Quick Facts:
Host and nectar plant to Monarch Butterflies
Native in majority US and Canada, excluding West Coast and Northern East Coast
Hardy in zones 3-9
Prefers full sun, may tolerate partial shade
Needs well-drained soil, medium moist to dry
Green flowers bloom mid summer
Grows 1-2 feet tall
Space 1 – 1 1/2 feet apart
Seeds need 30 day cold stratification or sow in fall/winter
Short Green Milkweed Plants Get No Respect
Pity the Short Green Milkweed. It has a snazzy nickname (Green Comet!) that is usually ditched in favor of the somewhat unfair moniker, “Small Green.” The plant is actually not necessarily the lowest to the ground in the butterfly garden–it has a height range of 1-3 feet.
It’s frequently overlooked because it doesn’t tend to grow in colonies or mass groupings. It usually develops as a single- or dual-stemmed unbranched plant that prefers to keep some distance from any neighbors. Also, its light green umbels are not especially showy–they cluster in 2- to 3-inch half-spheres of 20-80 small blossoms, looking somewhat like gigantic green raspberries.
These umbels do provide nectar when they bloom for 3 weeks or so in the early summer (late June or early July), but the real value to the butterfly enthusiast probably lies in the leaves. The leaves are relatively large (about 5 inches long) and range in shape from thin lances to plump ovals. The Short Green Milkweed is not particular about moisture–it will grow in very dry to very moist soils as long as the medium is well-drained–but the amount of water it receives determines the shape of the leaves. Dry conditions lead to long, lean leaves and abundant water gives the leaves a fuller, more rounded profile. No matter the shape, adult butterflies recognize the leaves as worthy egg receptacles and delicious food for the resulting caterpillars!
Dependable, But Not Flashy
As you’ve gathered by now, Asclepias viridiflora really only needs two things–well-drained soil (of any type, even salty or clay-infused) and a relatively uncrowded location. It will grow in full sun to mostly shade. The plant’s substantial taproot means that once situated, the Short Green Milkweed wants to be left alone. It works well as a “set it and forget it” addition to a landscape.
Why include this diminutive, non-flashy herb in your garden? In addition to helping preserve a large diversity of native milkweed varieties, planting it can be viewed as an assurance for your milkweed supply. It doesn’t take many seasons for a butterfly gardener to realize that there may be no such thing as “too much milkweed!” A banner year for baby caterpillars means food for their hungry mouths may quickly be in short supply. Best to have plenty of milkweed leaves at the ready! You can think of Short Green Milkweed as a sack of sugar tucked away in your pantry–a staple that’s invaluable to have on hand when you need it!
Starting Asclepias viridiflora seeds
The short green milkweed seeds need 30 Day Cold Stratification for spring planting. You may fall sow and let nature take care of the stratification. After stratification, plant the seeds up to 1/8” deep in the soil. If starting indoors, transplant after your last frost. Space the plants 12-18 inches apart.