Monarchs cannot survive without milkweed; their caterpillars only eat milkweed plants (Asclepias spp.), and monarch butterflies need milkweed to lay their eggs. With shifting land management practices, we have lost much milkweed from the landscape.
Please plant milkweed to support monarch populations, and their incredible migration! Planting milkweed is a great way to help other pollinators too, as they provide valuable nectar resources to a diverse suite of bees and butterflies. For a brief how-to flyer on planting and gardening, download MJV's Gardening for Monarchs.
Adult monarchs will drink the nectar of many flowers in addition to milkweed; in fact they need sources of nectar to nourish them throughout the entire growing season. Include a variety of native flowering species with different bloom times to provide monarchs with the food they need to reproduce in the spring and summer and to migrate in the fall. Offering a wide array of native nectar plants will attract monarchs and many other butterflies and pollinators to your habitat all season long.
Find appropriate native monarch nectar plants for your region using the Xerces Society's Monarch Nectar Guides. You can also check with local native plant nurseries or greenhouses for their recommendations of good pollinator plants for your area.
Key Habitat Considerations
- Habitat can be created in any open space protected from untimely mowing or pesticide application.
- Native milkweeds provide food for monarch caterpillars.
- Native flowers provide food for adult butterflies. A combination of early, middle and late blooming species, with overlap in flowering times, will fuel butterfly breeding and migration and provide beautiful blooms season-long.
- Insecticides should never be used in or surrounding pollinator habitat. Limit use of herbicides within and surrounding the habitat only to control invasive or noxious weeds.
Finding Milkweed Seeds and Plants for Purchase
The Xerces Society has launched a Milkweed Seed Finder database to make locating seeds in your state easier. Search for seeds in your state and contact the native plant nurseries that are listed to order milkweed seeds or plugs, then get planting! We recommend calling ahead to check availability of milkweed plants at the nurseries of your choice, as inventory can vary through the course of a season and from year to year.
Visit Monarch Watch’s Milkweed Market or directory of milkweed vendors to find native milkweed seeds and plants available in your region. The Milkweed Market offers flats of milkweed plugs (plants) that were grown from seeds sent to Monarch Watch by volunteers from across the country. Order plants grown from the seeds that were collected in your region, and make sure to collect and send seeds from your area to Monarch Watch next year. Monarch Watch is now accepting 2018 pre-orders! Get your orders in early to notify Monarch Watch of the demand in your area; find out more here.
For those of you in the desert southwest, the Southwest Monarch Study has a resource on their website with desert southwest milkweed providers and also provides more detailed information on establishing Monarch Waystations in this region.
If you live in the Western US, the Pacific Grove Museum of Natural History has free milkweed and nectar plant seeds available on their website.
Finding Milkweed for Collection
If you plan to grow your own milkweeds, or add milkweeds to your current site, you can collect seeds when the milkweed pods are ready to burst (this occurs in the fall in the northern U.S.). Once you have collected seeds, remove them from the pods and store them in an airtight container in a cool and dry environment (such as a basement or garage) until you are ready to use them. It is best to include a moisture remover (i.e. Silica gel) in your seed storage container. If the seeds are moist for a long period of time, they will start to rot and eventually die. Seeds collected in the Northern US will not germinate without cold stratification.
Most milkweed species grow particularly well in disturbed areas, so start by looking in the following places: roadsides, pastures, along railroad tracks, bike paths, highway medians, agricultural field margins, vacant land, cultivated gardens, and parks..
Selecting Milkweed Species for Planting
- Download our milkweed information sheet for a list of milkweed species prioritized in your region that are known to be used by monarchs and easy to establish in gardens and fields.
- If you want to learn even more, visit the Biota of North America Program's Asclepias page for distribution maps for each milkweed species across the continent.
- Visit Monarch Watch's milkweed profiles page for more information on each of the recommended species.
- Especially for habitat restoration projects, we recommend using milkweed plant materials originally sourced as close to the planting location as possible. See the USFS Celebrating Wildflowers website for more information.
- The Xerces Society has species profiles for milkweed species in the western U.S., which can help you select species for your region and conditions.
Planting and Growing Milkweed (Seeds or Plugs)
Most seeds of temperate plants should be vernalized (cold treated); this ensures a higher germination rate than if seeds are sowed without this pre-treatment. Many of the southern species, such as tropical milkweed, will grow without cold-treatment. The most successful means of milkweed vernalization is through stratification. By stratifying, or subjecting seeds to a cold/moist environment for a short period of time, you simulate the conditions of a seed's natural break of dormancy that occurs when the seeds spend the winter in the ground. To stratify, first obtain a substrate. Peat has been found to produce the best results, in addition, peat/clay also work well. Secondly, moisten the substrate with water and place the seeds in the cold soil. Store the seeds in a dark place (a refrigerator crisper works well) with a temperature of approximately 5°C for a minimum of 3 weeks up to 3 months. To allow for natural stratification, sow collected seeds directly into a mulched bed in the fall and the seed will germinate the following spring.
If you have grow lights or a greenhouse, it is best to start your milkweed seeds indoors a couple of months before you are able to transplant them outdoors. Fill the seedling trays approximately ¾ with potting soil (light, well-drained soils work best for most species) and scatter 3-4 seeds per cup and then cover the seeds with an additional ¼ inch of soil. The soil is then fully saturated with water and placed either in a sunny window or directly under the grow lights; they need a lot of light and warmth to germinate and grow. It's best to keep the temperature at 26/24°C day/night with a 16-hour photo phase. Keep the soil moist, but don't overdo it. If the seedlings are too wet, fungal growth can occur and kill the seedlings. The seeds will take approximately 10 days to germinate. Once there are 4 true leaves on the seedlings (the seedlings will be approximately 3 inches tall), the plants can be transplanted into your garden. Most milkweed species do best in full sunlight, so choose an open area with lots of sun. Plant the seedlings 1-2 feet apart. The seedlings should be watered frequently; mulch can be used to help hold in the moisture around the plants.
For indoor use, plant the seeds just beneath the soil surface using a rather deep pot, as they have a long taproot. Once the plants are in the seedling stage, fertilize once a week. To encourage fullness and more leaves, you can pinch off the top set of leaves (when there are at least two sets of leaves) to promote branching. It takes at least a month for the plant to be ready for the larvae to eat. Once the plant is big enough, you can simply place the entire plant, pot and all, into the cage. After the larvae have eaten the leaves, simply cut the plant off about two inches above the soil and new shoots will grow in 3-4 weeks.
When planting seed outdoors, keep in mind that all plants have optimal soil temperatures for germination, which makes propagation a little more difficult. It is best to plant the seeds as early as possible, but make sure that you plant after the last frost. Sow milkweed seeds by scattering them on the soil surface 1/4-1/2 inch apart, and then cover with about 1/4 inch of additional soil. Water frequently after planting until plants become established. Many species need to be vernalized (cold treated) before planting. See Monarch Watch's milkweed propagation guide for recommendations on growing milkweed.
Plugs can be placed directly into the ground. First, dig a small hole to fit the roots and soil of the potted milkweed plug/plant that you have. Place the plant plug into the hole so that the roots are entirely covered and the stem and leaves of the plant are above ground. Spread remaining soil from the hole around the plant and gently pack it down. Water frequently after planting until the plant becomes established. Plugs can be planted in the spring or summer.
Other Useful Resources
- Archived webinar series on topics ranging from biology and research to habitat restoration and augmentation.
- Monarch identification and monitoring training video series produced by the Monarch Larva Monitoring Project.
- Pollinator Habitat Tips produced by Pheasants Forever/Quail Forever.
- The Xerces Society Project Milkweed website.
- Already have a monarch habitat or project? Share it on our Monarch Conservation Efforts Map, or join a habitat certification project!