# When to plant milkweed

> There are two good windows for milkweed and one bad one. Fall suits seed; late spring suits plants; midsummer suits almost nothing.

Source: https://milkweedusa.com/guides/when-to-plant-milkweed/  
Licence: CC BY 4.0 (Milkweed USA)

## The short answer

**Sow seed in the fall.** Late October through December in most of the country, so winter does the stratification for you and the seed germinates on its own schedule in spring.

**Plant potted plants and plugs in late spring**, after your last frost, or in early fall in the South where roots can establish through a mild winter.

**Avoid planting anything in midsummer.** Milkweed transplanted in July has to build a root system in the worst possible conditions, and taprooted species rarely recover.

## Fall sowing, region by region

| Region | Sow seed outdoors | Plant plugs |
| --- | --- | --- |
| Northeast & Upper Midwest | Late Oct – early Dec | Late May – June, or early Sept |
| Mid-Atlantic & Ohio Valley | Nov – Dec | May, or Sept |
| Southeast & Gulf Coast | Nov – Jan | Oct – Nov, or March |
| Great Plains | Oct – Nov | May – early June |
| Mountain West | Sept – Nov, before hard freeze | Late May – June |
| Desert Southwest | Nov – Jan | Oct – Nov, or Feb – March |
| Pacific Northwest | Oct – Nov | April – May |
| California | Oct – Dec, to use winter rain | Nov – Jan |

The principle behind the table is simple: sow when the seed will next experience a real cold, damp period, and plant when roots can grow without the top of the plant being cooked.

## Why fall beats spring for seed

Fall sowing costs nothing, needs no fridge space, and produces stronger plants. Seed sown in November sits through winter, breaks dormancy naturally, and germinates in the first warm spell, often weeks before you could have got spring-sown seedlings into the ground. Those seedlings then have the whole growing season to build roots.

The one real risk is a mild, wet winter that lets seed germinate in a January warm spell and then kills the seedlings in February. That is a genuine concern in the Southeast and along the Pacific Coast, which is why fridge stratification followed by a February or March sowing is a reasonable alternative there.

## Spring sowing: what to do if you missed fall

Stratify in the fridge for 30 days and sow indoors six to eight weeks before your last frost. Grow the seedlings on under lights or on a bright windowsill, harden them off over a week, and plant out after the frost date. You will be about a month behind fall-sown plants by midsummer, and level with them by year two.

## Planting nursery plants

Potted milkweed goes in best in late spring, once the soil has genuinely warmed. Points that matter:

- Water in thoroughly, then water weekly for the first six weeks and stop. Established milkweed of most species wants far less water than gardeners give it.
- Do not add compost or fertiliser to the planting hole for dry-country species. Butterfly weed in enriched soil grows soft and flops.
- Plant at the same depth it was in the pot. Burying the crown invites rot.
- Do not tease out the roots of taprooted species. Slide the plant in with the root ball intact.

> [warn] Check that any nursery plant has not been treated with neonicotinoid insecticides. Systemic neonics persist in leaf tissue for months and will kill the caterpillars the plant was bought to feed. Ask directly, and buy from native plant nurseries who can answer the question.

## When milkweed emerges in spring

This causes more panic than any other question. Milkweed is late. Butterfly weed in particular can be four to six weeks behind the rest of the border, and in cold regions it may not show until late May or even June.

Mark every milkweed with a stake in the fall. More established plants are lost to spring digging and enthusiastic mulching than to any pest.

## Cutting back and fall management

Leave the stems standing through winter if you can. They hold seed, shelter overwintering insects, and look good under frost. Cut them back in late winter, before new growth starts.

The exception is tropical milkweed in zone 9 and warmer, which should be cut hard in October and kept cut through February to prevent winter monarch breeding and the parasite build-up that goes with it.

## Questions

**What is the best month to plant milkweed seeds?**

November in most of the United States. Fall sowing lets winter supply the cold stratification the seed needs, and germination happens naturally in early spring. If you have missed fall, stratify in the fridge for 30 days and sow indoors six to eight weeks before your last frost.

**Can you plant milkweed in the summer?**

Potted plants can go in during early summer if you water them consistently, but midsummer is the worst time for transplanting, especially for taprooted species like butterfly weed. Sowing seed in summer usually fails because the seed has had no cold period.

**How late can you plant milkweed?**

Seed can be sown outdoors any time before the ground freezes, and in mild regions right through winter. Potted plants should go in at least six weeks before your first hard frost so the roots can settle.

## References

- Luna, T. and Dumroese, R. K. (2013). Monarchs (Danaus plexippus) and milkweeds (Asclepias species): the current situation and methods for propagating milkweeds. Native Plants Journal 14(1): 5–15. https://doi.org/10.3368/npj.14.1.5
- Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide
- Monarch Joint Venture (2026). Monarch conservation resources and monitoring protocols. Monarch Joint Venture, St Paul, Minnesota. https://monarchjointventure.org/

## How to cite

Milkweed USA. (2026). When to plant milkweed. https://milkweedusa.com/guides/when-to-plant-milkweed/