Growing Milkweed: How To Cultivate Healthy Asclepias For Monarchs And Other Pollinators

Milkweed is a group of native plants that are special in that they serve as the sole hosts for monarch butterfly caterpillars. If you know how to grow milkweed, you can help declining monarch populations rebound.

Growing milkweed also supports other native pollinators, so it’s a great plant to include in most gardens. There are several species and varieties, so look for the types native to your area that will grow best in your conditions. Milkweed is a great addition to a pollinator garden designed to attract butterflies.

Caring for Milkweed

Growing milkweed plants is easy if you provide the right conditions. These are the care needs for common milkweed. Growing conditions for milkweed varieties vary a little, so make sure you know which one you have and that it is appropriate for your garden.

Light

Common milkweed and most other types need full sun.

Temperature & Humidity

As native plants, milkweeds are hardy throughout their ranges and fit well into many types of butterfly gardens. Common milkweed is hardy in USDA hardiness zones 3 through 9 and tolerates wide temperature ranges. Extreme heat or humidity can be problematic.

Water

Common milkweed does not need to be watered once established, except in very dry conditions.

Fertilizing

Milkweed tolerates poor soil and does not need to be fertilized.

Soil & Compost

Common milkweed grows best in dry, well-drained soil. It tolerates poor, rocky soil. Swamp milkweed is an exception and needs moist soil. It is best to determine soil texture before planting.

Where to Plant Milkweed

When planting milkweed plants, know what type you have. Most species, including common milkweeds, will grow best in soil that tends toward dryness and that drains very well. Most also need a spot with full sun. They tolerate poor soil and even rocky soil. You can also grow milkweed in a large container garden. Just be sure they have good drainage.

How to Plant Milkweed

If you’re using transplants, plant milkweeds in the spring after the last frost. Plant them 28 to 24 inches (46 to 61 cm) apart. While milkweeds tolerate poor soil, you can help them thrive by mixing amendments from your compost pile into the soil before planting. Water regularly during the first growing season to help the plants establish strong, deep roots.

Plant milkweeds behind mounding perennials or groundcovers to hide the foliage. The leaves get damaged throughout the growing season as insects feed on them and begin to look less attractive.

Milkweed takes a few years to flower, so don’t expect to see anything but foliage until year three. The leaves are still valuable, of course, as this is what feeds the caterpillars.

Prune and Deadhead Milkweed

Deadhead milkweed flowers as soon as they are spent to keep the plants looking tidy and to prolong blooming. If you want to propagate them or let the plants reseed themselves, allow the second flush of flowers to remain in place and produce seedpods.

You can cut milkweeds back in fall to tidy the garden. Leave a few inches of growth for wildlife habitat and look for new shoots in spring.

Problems, Pests & Diseases

Several insects feed on milkweed, but many are native and evolved with the plants. If you grow enough milkweed, some loss to these pests shouldn’t be a problem. Never use pesticides on or near milkweeds, as this will harm monarchs.

Look for aphids, which can cause significant damage. You can control aphids by physically removing them with a spray of water. Use traps to manage snails and slugs, which can damage fresh, young milkweed plants.

Fungal infections may be an issue, so look for signs of infections and remove and destroy affected leaves or plants. Root rot can also be a concern if the soil gets too wet and doesn’t drain well.

Propagating Milkweed

Growing milkweed seeds is easy and a great way to propagate these native plants. Older plants do not transplant well, so growing milkweed from seed or taking cuttings are better options than division.

To propagate by seed, collect seeds from pods in the fall. Wait for the pods to turn brown and start to open. Or, let the seed pods stay in place, and the plants will reseed naturally. If you are planting seeds by hand, sow them in the fall. Milkweed seeds need to be cold stratified, so they will not necessarily germinate if planted in spring.

Take milkweed cuttings in the middle of summer when the stems are still green. Remove about four inches (10 cm) of stem with a few pairs of leaves. Remove the lower leaves, keeping two pairs in place at the top, and root the cutting in moist potting mix.

Frequently Asked Questions

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