Piedmont Gardener

Butterfly Weed (Asclepias tuberosa)

In the southeastern US piedmont region where I live, I am happy to report that more and more homeowners are adding native pollinator gardens to their landscapes. By providing sources of pollen, nectar, and leaves of plants that native bees, butterflies, moths, wasps, etc. rely on, we are all helping to replace at least some of the native ecosystems obliterated by urbanization that once fed these insects. As Douglas Tallamy explains in his book, Bringing Nature Home, if we lose our native pollinators and other insects, we also lose the native wildlife that eats these insects — birds, bats, frogs, etc.

A freshly emerged Monarch Butterfly

One of the poster-insects for the plight of our native pollinators is the Monarch Butterfly. Reports seem to vary every year recently regarding the status of this beautiful species, but it seems clear that we should all continue to add to our landscapes the native food plants that this butterfly relies on: milkweeds (Asclepias spp.)

Swamp Milkweed (A. incarnata)

Milkweeds are a test of patience for gardeners. New transplants don’t usually bloom prolifically the first year after planting. These plants spend that first year establishing healthy root systems. But by their third year in your garden, you will agree that milkweeds are worth the wait — for the beauty of their prolonged flowering, for their fat, brown pods from which seeds escape on silken parachutes, and for the diversity of pollinators that dine on their flowers, and the Monarch Butterfly caterpillars that devour the plants.

A honeybee enjoying Swamp Milkweed blooms.

For gardeners wondering which species of milkweed to try in their gardens, I recommend three options. These are the easiest to grow, and also the most readily available in the trade.

• Swamp Milkweed (A. incarnata) is native to moist areas and can handle some shade. However, it thrives in standard garden beds, as long as you water it during droughts, and perhaps a bit extra during its first year as it is establishing. In return, you will get three-foot-tall plants covered in clusters of pink flowers. There’s also a white-blooming variety of this species, but I think the pink forms are much lovelier. A well-established plant will bloom for at least a month, and will be visited dawn to dusk by happy pollinators. If you’re lucky, these visitors will include some Monarch butterflies.

Honeybees on Butterfly Weed

• Butterfly Weed (A. tuberosa) is native to hot, sunny hillsides. It’s not unusual to see it growing on unmowed road banks in my region. The trick to this species that produces bright orange flowers is excellent drainage. If it sits for long in too-moist soil, it will forsake you. The plants I’ve added grow bigger every year, producing more and more flowering branches literally abuzz with happy pollinators.

Common Milkweed (A. syriaca)

• Common Milkweed (A. syriaca) thrives in moist, sunny places. It is not as showy as the first two species above, but it seems to be the favorite food plant of Monarch Butterfly caterpillars, perhaps because it is the most commonly occurring milkweed species on patches of undeveloped land. I tucked mine toward the back of a flower bed, where they can grow tall while waiting for Monarchs to find them. I planted mine in my boulder bed, and they haven’t bloomed for me, possibly because they don’t get quite enough sun. But they grow well, producing tall, green plants, and last year Monarch caterpillars ate them literally to the ground. However, the plants returned in greater numbers this year, which is when I realized that this species spreads via running rhizomes. As Matt Gocke, Greenhouse and Nursery Manger at the North Carolina Botanical Garden told me, you plant this species once, and you will never need to plant it again, because of its ability to spread itself via rhizomes.

Milkweed Pests

Milkweeds are slow to emerge in spring, far later than many other native perennials. But once they appear, they grow quickly, and soon the pollinator visits begin. Two pests will also eventually show up.

Oleander aphids on Common Milkweed

Bright orange Oleander aphids inevitably appear on every milkweed species I grow, but they seem to favor Common Milkweed. So-called because they also feed on oleanders, these aphids are orange to warn potential predators that they are poisonous, having ingested the toxins in milkweed that cause deer, rabbits, and other plant-eaters to pass them by. These aphid infestations can get pretty ugly. I control mine by donning garden gloves and simultaneously spraying the stems with a strong jet of water while rubbing off the aphids with my fingers. Aphids are poor climbers; once knocked down by the water, they have trouble getting back up the stems.

A Milkweed bug

Milkweed bugs usually show up eventually on some of my milkweeds. These can be destructive to developing seed pods, because they suck out the nutrients in the pods, thereby stunting them. If they get out of hand on my plants, with my gloves on, I pick them off and drop them in a jar of soapy water, where they quickly die. Most years, I never see very many of these insects, which makes me wonder if some bird eats them despite their possible toxicity.

A Few Other Milkweed Species

Snowberry Clearwing moth visiting flowers of Whorled Milkweed.

Being a somewhat obsessive gardener, if I like a genus of native plants, I’ll often try to grow as many different species as I can. Thus, I grow a few additional species of milkweed.  This is the second year for my Whorled Milkweed (A. verticillata). Until it blooms, you wouldn’t even believe it’s a milkweed. That’s how un-milkweed-like its leaves look, at least to me. But its small white clusters of flowers are unmistakably milkweed blooms, and this year the plant has formed a lovely small shrubby plant that continues to produce flowers popular with an array of pollinators.

Without the flowers, I’d never guess the identity of Whorled Milkweed.

Red Milkweed (A. rubra)

The flowers of Red Milkweed are similar to those of Swamp Milkweed, and they share a preference for the same growing conditions. I grow mine in a pot that sits in my summer water feature. It blooms in early spring, but doesn’t re-bloom.

Fewflower Milkweed (A. lanceolata)

Fewflower Milkweed is native to swampy parts of the coastal plain region up and down the eastern coast of the US. I planted this in one of my summer water feature pots last year, but it didn’t bloom. But this year, beginning about two weeks ago and still going strong, the plant began to produce clusters of peachy-orange flowers. The color is not as in-your-face as that of Butterfly Weed flowers, but as the common name implies, each flower cluster contains a relatively small number of flowers. They are as popular with pollinators as the other milkweed species, but probably not a practical choice for most piedmont gardeners.

Swamp Milkweed pods releasing their seeds.

I think native milkweeds should be on every gardener’s list of must-have perennials. For an investment of some patience on your part, you will be rewarded with prolonged, colorful blooms visited by swarms of bees and butterflies. And if you’re really lucky, perhaps you’ll get the chance to watch a Monarch caterpillar transform into a chrysalis, and then a butterfly, as I did last year.

Chrysalis of a Monarch Butterfly in development

Fall is a great time to plant milkweeds in your garden, and you can get the three species I suggested — plus perhaps a few more — at the North Carolina Botanical Garden’s Fall Plant Sale next month. I’ll be there on Member’s Night to get first crack at all the wonderful plants that will be offered. I hope I’ll see you there!