Milkweed (Asclepias) seeds germinate best under warm soil conditions. The seeds need a cold, dormant period, known as stratification, to germinate.
- Need sandy or gravelly soils (except the Clay form which does well in heavier soils including dry clay.)
- Does best with gravel mulches.
- After their second growing season, only requires deep but infrequent watering. Plant in full hot sun.
- 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.
- 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.
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.
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.
Preferred growing conditions:
- 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.
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 tuberosa (Butterfly Weed) milkweed has attractive, bright orange flowers in late spring and is a nectar source for bees and butterflies.