Swamp Milkweed (Asclepias Incarnata). Grow this North American native for the sweet scent, the butterflies, bees, and the beautiful mid- to late-season colour. Allow the Monarch butterfly larvae to munch all the leaves they want and watch them pupate over the winter— the plant will return next spring. Easy from seed with winter-sowing. Won't reliably re-seed in one area, since the fluffy seedheads travel long distances in the wind. Extremely hardy, but not the best choice for drought-prone areas.
|How To Grow||Sow seed in February indoors in a soil-less mix, moisten the medium, then cold stratify by placing in a freezer for 3 to 4 weeks. After that, bring the container back into the warmth and germinate at 20 C (70 F) for 21 to 28 days. After germination, grow on under lights at a slightly cooler temperature before hardening off and transplanting to a sunny spot in the garden with moist to wet soil. Direct fall sowing is also highly recommended as this allows any dormant seed to be naturally stratified during the winter.|
|Blooming Season Begins||High Summer|
|Propagation||Start Indoors or Sow Direct in Fall|
|Days to Emergence||21 to 28|
|Height||Medium Tall (60 to 90 cm)(24 to 36")|
|Frost Tolerance||Winter Hardy|
|Degree of Difficulty||Easy|
|Heritage||Native of Canada|
|Suggested uses.||A must have specie for wet site pollinator and butterfly gardens.
Integral specie in native wetland seed mixes for both rejuvenation and regeneration.
Use in sunny wet areas in formal gardens.
|Requires Stratification||Many native plants produce seed that is viable but dormant. This means that while the seed has all the internal structures and nutrients required to germinate, the seed coat is so hard, water cannot pass through it and initiate germination. When seed is in this state, it is known as being dormant. Seed dormancy is a naturally selected for trait that protects the seed of many plants allowing them to safely overwinter and then be ready to sprout in more favourable conditions in spring.
The remedy to naturally breaking seed dormancy is typically the passing of time. In particular, seed overwintering outside and experiencing the natural freeze thaw cycles that occur in late fall, winter and early spring. To artificially break seed dormancy, sow the seed in a soil-less mix, water than chill in a refrigerator for a set period of time. This dormancy breaking process is called stratification.