5 Types of Milkweed in Rhode Island (AND One to Avoid!)

“What types of milkweed should I plant in my garden?”

Common Milkweed in Rhode Island

This may seem like a crazy question if you’re just getting started with native gardening. Why would you want to plant a weed?!

But milkweed isn’t a weed at all. Instead, it’s a flowering plant that attracts butterflies (think Monarchs), native bees, and other pollinating insects, which is an excellent thing!

This article will give you information about common types of milkweed in your area and which ones will be best for your garden. And, keep reading to the end to learn about a kind of milkweed you want to avoid!

5 Types of Milkweed in Rhode Island:


#1. Common Milkweed

  • Asclepias syriaca

Types of Milkweed found in Rhode Island

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Growing Information:

  • USDA Hardiness Zone: 3-9
  • Life Cycle: Perennial
  • Approximate Mature Size: 3 to 5 feet; up to 8 feet.
  • Bloom Time: June to August

Common Milkweed is the species most people think of when they hear the name milkweed. It’s a hardy perennial and one of the most common types of milkweed in Rhode Island.

Milkweed gets its name from the latex or milky white secretions produced if the stem or leaves are broken. The leaves are oval, about six to eight inches long, and dark green.

Milkweed species that live in Rhode Island

The blooms of the Common Milkweed plant are clusters of tiny flowers on stems that radiate from the larger central stem. These clusters are called umbels. The fragrant flowers are greenish-pink, pink, or purple and give way to 4-inch seed pods in the late summer and early fall. Initially, the pods are green but slowly mature to brown. Eventually, they split open, revealing seeds and fluffy white material called coma that allows the seeds to disperse on the wind.

Common Milkweed is an incredibly important wildflower in Rhode Island.

Over 450 native insects feed on the nectar, sap, leaves, and flowers. In addition, it’s an important food source for caterpillars of the Monarch Butterfly (Danuas plexippus). The adult butterflies lay their eggs exclusively on members of the milkweed (Asclepias) family.

Common Milkweed species in Rhode Island

Interestingly, all milkweed species contain cardiac glycoside compounds. Monarch Butterflies and other insects consume milkweed and store the compounds in their bodies. Potential predators have learned to steer clear of Monarchs to avoid this dangerous and bitter poison!

Common Milkweed is relatively easy to grow, and it’s one of the easiest ways you can help support Monarch Butterflies. You’ll need a place that receives full sun for planting. Common Milkweed does best in well-drained areas but isn’t picky about soil and can be grown in clay, loamy, or sandy areas. They tolerate poor soils and don’t need to be fertilized. It’s essential never to use pesticides on these plants since they kill species like Monarch Butterflies.

Common Milkweed can spread by seed, or underground rhizomes, which are root colonies. This means you can add Common Milkweed to your garden by directly sowing seeds or planting cuttings from an existing plant.


#2. Whorled Milkweed

  • Asclepias verticillata

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Growing Information:

  • USDA Hardiness Zone: 3-10
  • Life Cycle: Perennial
  • Approximate Mature Size: 1 to 3 feet
  • Bloom Time: May to September

Whorled Milkweed is the most broadly distributed milkweed species in Rhode Island.

This unique perennial is sometimes overlooked by gardeners who want to plant milkweed. Compared to other varieties, it has a narrow stem and spiky leaves arranged in a spiral pattern. When not in bloom, it easily blends in among grasses.

It blooms from May to September, forming flat-topped clusters of small greenish-white flowers on the end of each stem. The flowers attract various insects, including bees, wasps, butterflies, skippers, beetles, and flies.

Whorled Milkweed is still a welcome host plant for Monarch Butterfly caterpillars despite its unique appearance. Since this species is one of the last milkweeds to die back in the fall, it’s a great late-season host for Monarchs preparing to migrate south!

This delicate-looking wildflower can easily grow from seed, but it may not flower the first year. It can be grown in full sun or partial shade. Whorled Milkweed thrives in various habitats, including fields, pastures, roadsides, dry prairies, dry slopes, woodlands, and meadows. Unfortunately, it’s highly poisonous to livestock and is considered a nuisance weed in agricultural areas.

It grows best in dry soil of various types, including sandy, rocky, and clay soils. It can also be grown in moist, average garden soil. Keep in mind that it is an aggressive spreader by seeds and underground rhizomes, so you may not want to choose this milkweed if you have a limited area for gardening.


#3. Butterfly Weed

  • Asclepias tuberosa

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Growing Information:

  • USDA Hardiness Zone: 3-9
  • Life Cycle: Perennial
  • Approximate Mature Size: 2 to 3 feet
  • Bloom Time: May to September

Butterfly Weed is a showy member of the milkweed family. Sometimes called Orange Milkweed, this perennial wildflower features large flat-topped clusters of tiny flowers that grow 2 to 5 inches across. The blooms are brilliant orange or yellow.

Interestingly, its dark green leaves and stems don’t produce the same milky sap as other species of milkweed in Rhode Island.

Butterfly Weed is an excellent choice for gardens and or wildflower meadows. The beautiful flowers are fragrant and are ideal for cut flower arrangements. They also attract native bees, butterflies, and honeybees to your garden. Butterfly Weed is also a host plant for Monarch, Gray Hairstreak, and Queen butterfly caterpillars.

This native flower is a great low-maintenance choice for the home gardener. Butterfly Weed’s deep taproots mean you’ll never need to water it once it’s established. In addition, this plant is highly drought tolerant and thrives in full sun. Butterfly Weed also does fine without any fertilization but grows best in rocky or sandy soil.

Unlike Common Milkweed, this species doesn’t transplant well and should be started from seed.


#4. Poke Milkweed

  • Asclepias exaltata

Growing Information:

  • USDA Hardiness Zone: 3-9
  • Life Cycle: Perennial
  • Approximate Mature Size: 2 to 6 feet
  • Bloom Time: May to August

Poke Milkweed’s flower clusters are pendulous, hanging down from the plant like a weeping willow. They typically have about ten flowers, white with a green or lavender tinge. The leaves of the Poke Milkweed plant are dark green with purplish veins that stand out.

Unlike many milkweed species in Rhode Island, Poke Milkweed is often found in partial shade.

This species can be grown in partial shade to full sunlight in the garden. It prefers soil with moderate moisture and rich organic material. It can be grown successfully in many home gardens and is easy to start from seed.

Poke Milkweed is an excellent addition to any butterfly lover’s garden. It’s a host plant for the caterpillars of Monarchs, Great Spangled Fritillaries, Tiger Swallowtails, Skippers, and Pearl Crescents. Its blooms also attract various other bees and butterflies.


#5. Swamp Milkweed

  • Asclepias incarnata

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Growing Information:

  • USDA Hardiness Zone: 3-6
  • Life Cycle: Perennial
  • Approximate Mature Size: 3 to 5 feet
  • Bloom Time: June to October

As the name suggests, this moisture-loving perennial is typically found growing wild on creek banks and ditches or in openings in swamps, bogs, marshes, and other wet areas. So if you’re looking for a plant for the wet spot in your yard, Swamp Milkweed is a perfect choice.

This species thrives in wet, mucky clay soils. It’s great for planting around ponds or streams on your property. This species requires full sun to thrive and spreads through both seeds and underground rhizomes.

Like other milkweeds in Rhode Island, the blooms are clusters of smaller flowers. The light pink, purple, or white flowers of Swamp Milkweed will attract various species of native bees and butterflies to your garden. It’s also a host plant for monarch butterfly caterpillars.

RELATED: 31 Rabbit Resistant Plants to grow in Rhode Island! 


Tropical Milkweed

  • Asclepias curassavica

Growing Information:

  • USDA Hardiness Zone: 8-11
  • Life Cycle: Perennial
  • Approximate Mature Size: 3 to 4 feet
  • Bloom Time: March to November in temperate climates, year-round in tropical climates.

This non-native milkweed plant has become popular in recent years because of its flowers’ bright red coloring and how easy it is to plant and maintain.

Unfortunately, Tropical Milkweed planted in Rhode Island may do more harm than good.

It carries a parasite of Monarch Butterflies called Ophryocystis elektroscirrha, or OE, which can cause defects in the wings of Monarchs. Since it doesn’t die back and can bloom late, the plant itself may also confuse Monarchs by signaling a breeding season when it’s time to migrate.

To ensure you’re planting milkweed that will help your local ecosystem and attract native pollinators, always choose a native species!

Marketers of Tropical Milkweed seeds will use the names Mexican Milkweed, Bloodflower, Mexican Butterfly Weed, Mexican Orange Milkweed, and Semi-Tropical Milkweed. Steer clear of all of these!


Are you looking for more information on milkweed in Rhode Island?

Check out this guide!


Do you have milkweed in your garden?

What’s your favorite thing about this plant? Leave a comment below!

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One Comment

  1. Wintering in Florida, I have begun a monarch butterfly feeding area. I’ve planted 5 tropical milkweed, and have observed several life cycles of monarchs already this spring. I will be looking to encourage the monarchs when I return to Rhode Island. In my suburban yard at home I have multiple mature butterfly bushes and a yard full of flowering plants, shrubs and trees, but no milkweed…YET! I am looking now for seeds and plants local to my area I RI.