Growing Food for Monarchs

Milkweed plants are the only food source of monarch butterfly caterpillars. By planting milkweed in your garden, you help provide more food for these little jewels.

The plant is named for the milky, white sap that secretes from damaged leaves and stems. Milkweed sap is toxic and causes skin irritation. For monarch butterfly caterpillars, eating milkweed leaves offers protection, making them toxic to predators.

Milkweed varies from different regions and climates, but the flowers of all the plants look very similar so it’s easy to identify. Flowers are dainty and come in clusters, with a distinctive star-like shape and range in color from white, yellow, orange to red, purple, pink and green. Once established in sunny Southern California gardens, the plants are hardy, low maintenance and droughttolerant.

Narrow-leaved milkweed (Asclepias fascicularis) is native to Southern California. It grows prolifically on hillsides and canyons but is harder to find in nurseries. I’ve resorted to buying seeds to start my own. Tropical milkweed (Asclepias currassivica), also known as Mexican milkweed, is the most common variety grown in Southern California gardens and is easy to find in nurseries.

Native milkweed has a natural dormant period but tropical milkweed grows year-round and needs to be pruned significantly in the fall and early winter. It typically grows 3-4 feet tall and I cut my plants down to about 8 inches high. Pruning the plants also controls a protozoan parasite, a natural predator of the monarch.

My goal is to eventually grow only native milkweed in my garden, but I will probably always have some tropical milkweed showing up because it reseeds prolifically. It can be considered invasive because we don’t have the cold weather to keep it in check.

LESLIE CRAWFORD

I use milkweed as a filler rather than the main attraction. There are two reasons for that: the plant itself is wispy-looking at its healthiest but more importantly, after the monarch eggs hatch and the caterpillars start eating, you’ll have chewed up stalks in your garden, which is not the best look.

Nature is a delicate balance, but we can help beneficial bugs, butterflies and other pollinators by planting our gardens with food sources. Wouldn’t it be great to see native milkweed growing all around town in gardens and public spaces? Let’s do it!