How to Plant and Grow Milkweed

Grow Milkweed Growing Tips

Every school child learns about milkweed because this plant is an essential food for monarch butterfly caterpillars. There are actually several species of milkweed (Asclepias spp.), all of which are native to North America. They make beautiful, low-maintenance additions to most gardens and landscapes, where they attract a variety of pollinators with their flowers.

Milk juice for defense

Milkweed plants have developed two attractive defense mechanisms to deter predators. The main source of defense gives the plant its common name - milky white latex. The sticky sap and all parts of the plant contain large amounts of a compound toxic to all vertebrates. Monarch butterfly larvae have the ability to store this deadly compound in their bodies and are also toxic to vertebrates. This is what gives monarchs their characteristic foul taste, which repels predators.

A second defense of these plants is the sticky nature of the sap. Milkweed plants keep their sap under high pressure so that when they are damaged or stung, it is released quickly. In some cases, when the prey is a very small caterpillar (including unwary monarch larvae), this sticky fluid can trap the insect and drown it. The sap absorbs the chewing mouthparts of insects and prevents them from overheating.

Milkweed varieties

Butterfly weed

Butterfly weed (Asclepias tuberosa) offers fiery orange flowers that coordinate well with reds, yellows, and other warm hues in a perennial border. It grows up to 3 feet tall. Zones 3-9

Common milkweed

Common milkweed (Asclepias syriaca) has large ball-shaped clusters of deep pink flowers with a light fragrance. It grows 2 to 5 feet tall. Zones 3-9

Prairie milkweed

Prairie milkweed (Asclepias sillivandi) looks similar to common milkweed, except it has softer stems and leaves and larger flowers. The leaves have a distinct upward sweep. The plant grows to a height of 3 feet. Zones 3-7

Swamp milkweed

Swamp milkweed (Asclepias incarnata) is a long-blooming perennial with delightful rosy pink flowers. It grows 4-6 feet tall. Zones 3-8