Butterfly weed (Asclepias tuberosa) creates green foliage through summer and spring and clusters of small red, orange or yellow flowers. It rises at U.S. Department of Agriculture plant hardiness zones 4 through 10. The plant dies back each winter, but it yields out of its ongoing root system annually if it is maintained properly pruned. All areas of the butterfly weed are poisonous if eaten.
Wipe the pruning shears with a cloth soaked in rubbing alcohol to disinfect them before pruning, and then wipe them again when moving between plants. Wear heavy gloves to protect your hands in the sap, which can cause skin irritation.
Cut back the entire plant by one third to one-half its previous height in late winter or early spring before new growth emerges. Make the seams in 1/4-inch of a leaf or leaf bud so the bush doesn’t have bare stems poking out. Eliminate all pruning clippings in the bed after pruning and dispose of them.
Eliminate the wilting flowers after the first flush of blooms begin to fade, slowly cutting the blossom cluster above the topmost group of leaves on the stem. Removing the dead flowers prevents seed formation, which promotes butterfly weed to produce more flowers. Stop deadheading in late summer if you would like ornamental seed pods on the plants in autumn and winter.
Prune off the seed pods in late autumn or early winter should youn’t want the butterfly weed to self-seed, or simply to enhance the garden’s look. Wait until spring to cut back the entire plant.