In cold climates, milkweed will die back and return in spring with new growth. If you plant milkweed in fall, your plants will be able to establish themselves before winter. (Swamp milkweed is the only species that can handle overwatering, making it perfect for wet climates and rain gardens.) It’s easy to water too much in spring, leading to root rot in your plants. The key thing to remember is to not overwater your milkweed while it’s dormant. Oftentimes, milkweed is one of the last perennials to break dormancy in your garden. This is when the plant is focusing all its energy into developing a strong root system, and it won’t “wake up” until the soil warms. In spring, your milkweed plants will likely be dormant with no green leaves. Milkweed plants can be planted in spring or fall. It takes only a few caterpillars to defoliate an entire plant in a couple of weeks, but sure enough, the milkweed comes back every time. I’ve grown a few species of milkweed over the years, including butterflyweed, and found them to be impressively resilient-surviving not only major heat spells, but also oleander aphids, milkweed bugs, and many, many cycles of hungry striped caterpillars. It’s often seen growing in fields and along the sides of the road, which means it’s drought-tolerant and a good choice for low-maintenance perennial gardens. Grows 2 to 3 feet tall and has pale pink, purple, and white blooms.īutterflyweed does best in dry, sandy soil with little nutrition. Mexican whorled milkweed (Asclepias fascicularis): Native to the northwestern United States south to Baja California and north to Arizona. Grows 1 to 3 feet tall and has rosy-purple and pink blooms. Showy milkweed (Asclepias speciosa): Native to the western United States east to Illinois, south to Texas, and west to California. Grows 1 to 3 feet tall and has pink, lavender, or white blooms. Sandhill milkweed (Asclepias humistrata): Native from the southeast United States and north to North Carolina. Grows 4 to 5 feet tall and has mauve, pink, or white blooms. Swamp milkweed (Asclepias incarnate): Native from the northeast United States south to Georgia, west to Texas, and north to North Dakota.

Grows 1 to 2 feet tall and has light orange blooms. Grows 3 to 6 feet and has white and purple blooms.īutterflyweed (Asclepias tuberosa): Native from the northeast and eastern United States south to Florida, west to Texas, and north through Colorado to Minnesota. Not to worry, Northwesterners: You can still plant showy milkweed (Asclepias speciosa) or Mexican whorled milkweed (Asclepias fascicularis).Ĭommon milkweed (Asclepias syriaca): Native from the eastern United States south to Georgia and west through Tennessee to Kansas and Iowa. It’s native to most parts of the country (except the Northwest) and blooms in a brilliant orange or yellow. One of the most common, Asclepias tuberosa, is also known as butterflyweed.

If you want to plant new milkweed, there are several species of native milkweed in the US. This is not to say that gardeners in California and the coastal Southern states (or zones 8 through 11) who grow tropical milkweed should immediately rip it out-just remember to cut the plants back in late fall to reduce the spread of OE, promote new growth of fresh, healthy leaves, and encourage monarchs to finish their migration.

Once the plant goes dormant in winter and loses its leaves, OE is no longer a threat.īut with tropical milkweed, the leaves stay viable all winter long and make it more likely that a caterpillar will become infected.Ī report by the Monarch Joint Venture found that 49 percent of winter-breeding monarchs had OE infections, compared to only 9 percent of migratory monarchs sampled in Mexico and 15 percent of migratory monarchs sampled in the northern US and Canada. OE is found in all species of milkweed, but isn’t a problem with natives because the leaves are only desirable to caterpillars in the early stages of growth. When grown in warm climates where the plants don’t die back, the year-round tropical milkweed encourages monarch butterflies to overwinter in the Southern United States rather than continue their migration to Mexico.īy hatching and feeding on tropical milkweed, caterpillars have an increased chance of being infected with a protozoan parasite called Ophryocystis elektroscirrha (OE), which weakens them as adults. It’s also been found to do more harm than good. It’s not by any fault of their own, however: One of the most popular (and non-native) milkweed species, Asclepias curassavica or tropical milkweed, is widely sold in nurseries. Planting non-native milkweed is a common mistake that many people make. More importantly, strive to plant native milkweed for the monarchs. The next step is to plant milkweed in your garden. Choosing the right milkweed for your garden

Asclepias seedlings