Swamp Milkweed Seeds

Asclepias (Milkweed) are sun loving plants that are essential perennials for monarch butterflies providing food for caterpillars and nectar for adult butterflies. They bloom from mid-summer into early fall and, with their milky sap, are resistant to rabbits and deer.

Asclepias can be divided into two groups for plant care; Asclepias tuberosa with orange (sometimes yellow) flowers and all the other species with pink (sometimes white) flowers.

Planting Milkweed Seeds:

Milkweed (Asclepias) seeds germinate best under warm soil conditions. The seeds need a cold, dormant period, known as stratification, to germinate.

They can be successfully seeded outdoors in fall in areas that received frost, for spring germination. For mid to late spring planting, all species (A. tuberosa, A. syriaca, A. sullivantii, A. incarnata) will also germinate moderately well when seeded into warm ground after being stratified (chilled).

Dry stratification is done by placing dry seed in the refrigerator for 30 or more days. A more effective strategy is to moist stratify them by mixing seed with moist (not soggy) sand in a zip-lock plastic bag and place them in the refrigerator for 30 days. After 30 days of cold moist storage, the seed's natural chemical germination inhibitors have dissipated and are ready to sprout.

• Asclepias tuberosa (Orange Butterfly Weed) - this perennial stays dormant until later in the spring than many other plants, especially when grown in pots. It's fine to plant dormant plants; don't up-pot them for planting later in the growing season.

Preferred growing conditions:

1. Need sandy or gravelly soils (except the Clay form which does well in heavier soils including dry clay.)
2. Does best with gravel mulches.
3. After their second growing season, only requires deep but infrequent watering. Plant in full hot sun.
4. Just a few handfuls of compost and Yum Yum Mix added to the planting hole is enough. Don't plant into a rich, highly-amended soil.

Special comments:

• When planting dormant plants, water thoroughly after planting and wait to water again until the plant comes into active growth, at which time a deep watering every week or so is adequate. Take care not to overwater young transplants.
• Asclepias has a long, carrot-like tap root that should remain undisturbed after planting and should NOT ever be divided.
• Most Asclepias species are late to wake up in the spring, and will often be shipped as dormant plants. Don't despair if your milkweed is asleep. The white roots and woody crown are alive just waiting for consistently warm weather to wake up and begin to grow.these perennial species stay dormant later in the spring than many other plants, especially when they are grown in pots. It's fine to plant dormant plants; don't up-pot them for planting later in the growing season.

Preferred growing conditions:

1. These species grow in a wide range of soil types, including clay.
2. They don't need mulching (except in very hot climates).
3. These are moisture-loving perennials and do well in wet to moderately moist soil conditions.
4. Plant in full to part sun areas.
5. They like compost enriched soils at planting time.

Special comments:

• Asclepias syriaca and A. speciosa will spread to make big patches of plants and are best planted in parts of the landscape where they won't crowd out less vigorous plants. Not recommended for the prime spots in your perennial beds.
• Asclepias incarnata (Swamp Milkweed) is a more refined grower and is fine to include in perennial beds.

Oftentimes, Milkweeds won't grow much their first season in the ground, so be patient. They are establishing their root system and crown. By the second growing season, the plants will begin to get bigger and look more robust. Asclepias species are an odd bunch and don't behave like many other more familiar perennials. So be patient and accept their quirky nature.

Garden care:

1. Fertilize Asclepias just once in fall with Yum Yum Mix and Planters II. - Naturalized plantings don't need additional fertilization.
2. To encourage re-seeding and provide winter interest with their ornamental seed pods, leave the stems intact over the winter. In mid-spring, remove old stems just above ground level.
3. All species of Asclepias are late to emerge in the spring, so don't be concerned if other perennials come up first and they remain dormant.