Spider milkweed
Asclepias asperula · Apocynaceae
The gardener's calendar
Ideal time to plant spider milkweed: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Common name
- Showy milkweed, Butterfly weed
- Family
- Apocynaceae
- Type
- Perennial herb
- Blooming
- June to September
- Adult size
- 0.30 to 0.90 m in height
- Foliage
- Deciduous
- Hardiness
- Down to -15 °C
- Origin
- United States, central and southern regions
Care
Exposure
Plant showy milkweed in full sun for generous flowering. It tolerates partially shaded locations, but flower production decreases. Prefer an open situation where air circulates well to limit problems with stagnant humidity.
Watering
Once established, showy milkweed is very drought-tolerant and requires little watering. Water regularly during the first year to promote rooting. In summer, occasional watering is enough; don't overwater as it prefers dry to moderately moist conditions.
Soil
This plant adapts to many soil types, from sandy terrain to poor and well-drained soils. It tolerates acidity and slight alkalinity. Avoid compacted and poorly drained soils that promote water stagnation.
Fertilizer
Showy milkweed requires little fertilizer. A light application in spring is plenty. On poor soils, well-decomposed compost on the surface helps growth. Avoid excess nitrogen fertilizer, which reduces flowering.
Pruning
Cut stems to ground level in late autumn or early spring, after the aerial stems have disappeared. Remove faded flowers regularly to encourage prolonged flowering. Little pruning is necessary; this plant displays a natural and airy form.
Diseases and pests
Showy milkweed is generally robust and little susceptible to diseases. Powdery mildew can appear in very humid conditions; improve air circulation. Larvae of certain insects may feed on it, but this generally poses no problem. Little chemical treatment is necessary.
Did you know?
Showy milkweed is an essential host plant for the larvae of the monarch butterfly, an emblematic butterfly of North America. Without milkweed, this wonderful migratory butterfly cannot complete its life cycle, making it a plant of great ecological value in natural gardens. Its name 'Asclepias' pays tribute to Asclepius, the god of medicine in Greek mythology.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
- Lesser periwinkleVinca minor
- Greater periwinkleVinca major
- OleanderNerium oleander
- Asiatic jasmineTrachelospermum asiaticum
- Star jasmineTrachelospermum jasminoides
- AmatunguluCarissa macrocarpa
Tips generated and checked by Viridia — adapt them to your local climate.