Swamp Milkweed

Light Needs

Partial Sun to Full Sun

(At Least 5 Hours of Direct Sunlight)

Mature Height

3-4 Feet

Mature Spread

1-2 Feet

Growing Zones

3 to 8

Milkweed is the plant that attracts and supports the most butterfly species. Each variety of Milkweed is specific to species. Swamp Milkweed attracts mainly Monarch and Queen butterflies to lay their eggs and support the caterpillars with their foliage. The showy pink blooms also attract other insect pollinators throughout the summer. The only creature Milkweed does not attract is deer.

Swamp Milkweed is a common addition to an open meadow planting, but is also lovely in a Cottage Garden or as a backdrop in a mixed perennial border. Asclepias are native to the Baja area of Southern California and Arizona, although they are not the most drought tolerant plants. They originate from along rivers and flood plains, making them a good addition to a Rain Garden plan that could also double as a butterfly habitat.

Swamp Milkweed Care

Swamp Milkweed prefers a rich, well drained soil that will help to support vigorous foliage growth. An open, sunny spot is also preferred. Soil pH and texture can be average. A mulching of organic compost in the fall will help to improve the soil's moisture holding capacity and provide added nutrients that this perennial needs.

Swamp Milkweed only needs a cutting back late in the winter before new growth emerges. Seed heads left to stand through the winter provide food for birds and will help the Milkweed to self seed and naturalize. Dividing is not usually done. The late cleaning of the old growth also provides for the butterflies to hatch in the spring and move on to new growth to feed and develop into cocoons. Swamp Milkweed is best planted in an area that will be quiet and not have a lot of traffic. Dividing is not usually done with Milkweed. The plant forms a large taproot that does not like to be disturbed and will not survive relocation.

Swamp Milkweed Spacing

Swamp Milkweed has a mature height of 3-4 feet and a width of 10-12 inches. When planting in a large group, space plants at 12 inches on center. This will leave room for self wedding and spreading at a fairly quick rate.