- You will get 100+ Seeds of Swamp Rose Milkweed Flower Seeds. - Seller Notes: “Asclepias incarnate. U.S. Grown Seed. Tested 1/23-Germination 94%. Packed 1/23.”. - Soil Type: Clay, Loam, Peat, Sand. - Life Cycle: Perennial. - USDA Hardiness Zone (°F): 8 (10 to 20 °F). - Soil pH: Neutral. - Watering: Medium. - Sunlight: Full Sun. - Rose / Swamp Milkweed. American Native Wildflower. Milkweed is the primary food plant of Monarch Butterfly caterpillars. The monarch population has been decreasing by 50% a year for over ten years. The reason is not enough wild milkweed for the babies to eat. Once established this plant requires very little care. Not picky about soils. One plant of Rose/Swamp Milkweed will form a large clump by its spreading rhizomes, which can be divided. This happens the second season and beyond. Tough perennial. Some can live 5+ years. Does well in containers.100+ Quality heirloom seeds. - Some American Native Wildflower seeds need to go through a cold winter to germinate. This plant is one of them. They do this so the seed won’t sprout in fall, only to have the seedling not make it through a cold winter. I have stratified these seeds to simulate a cold winter(stratification) This raises the germination rate considerably. Thanks for looking!!. - Asclepias incarnate. - Full sun. - Early spring, soil temp 40F+. - SOW on surface. Press into soil 6"apart. Do not cover. Needs light to germinate. Keep moist. - Germination 14-28 Days. - Medium water. - Flowers are pink. Blooms from summer through fall.