Jenkins’ Seed Packets: Pink Swamp Milkweed

Pink Swamp Milkweed
Asclepias incarnata

Swamp milkweed is a native perennial wildflower with beautiful pink flowers that sit atop a sturdy stem and stout leaves. In mid-summer, its blooms attract numerous pollinator species, and in the fall it displays unique seedpods. Milkweeds are an essential food source for Monarch caterpillars and will bring lots of life to a wet, sunny garden bed.

Natural Habitat: Wet meadows. swamps
Light Requirements: Sun to part shade
Soil Requirements: Medium to wet
USDA Hardiness: Zones 3-9
Size: Height of 2’ to 4’ tall
Wildlife Value: Bees, butterflies
Deer Resistance: Resistant

Germination Requirements:

Swamp Milkweed seeds require 60 days Cold Moist Stratification (abbreviated CMS in many reference guides). Stratification is the process of pre-treating seeds to overcome the seeds’ natural inhibitors that prevent germination in less-than ideal circumstances. Cover the seeds lightly when you sow them. A general rule is to cover seeds to a depth equal to their height.

Cold Moist Stratification can be accomplished by sowing the seeds and setting them outside when temperatures are consistently below 40 degrees. Seeds can always be kept cold longer than the required number of days, so it is fine to sow these in December and leave them outside for the entire winter. They will germinate when the soil warms up in spring.

Alternately, you can mix the seeds with a small amount of moist (not wet) sand, perlite or vermiculite in a baggie and place it in a refrigerator for 60 days. If you choose to hold them there longer than 60 days, check the seeds periodically. Some seeds will germinate in the baggie. This is fine if you catch it early. After chilling the seeds for 60 days, sow them by spreading out the contents of the baggie on the surface of your medium.