Garden Oracle / Drought and Heat Tolerant Gardening / Tucson - Phoenix - Arizona - California

Growing Asclepias subulata:
Desert Milkweed

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Form: A subshrub with a woody base and herbaceous stems.
Leaf retention: Deciduous.
Growth rate: Moderate.
Mature Size: 4' high and wide.
Flowers: Small flowers in clusters, dull yellow to white, not showy.
Bloom: Spring through fall.
Fruit: Horn-shaped seed pods, 3" long, initially blue to green, containing plumed seeds.
Leaves: Small, narrow leaves appear during rain and drop in drought.
Stems: Blue to green, photosynthesizing, long, narrow, upright, no thorns.
Roots: This plant has a taproot.
Wildlife: It attracts butterflies, bees, and insects that feed on aphids. It is a caterpillar food plant for Queen and Monarch butterflies.
Toxic / Danger: All parts of this plant are toxic if ingested, and the sap is skin irritant.
Origin: California, Nevada, Arizona and Mexico.

Cultivation and Uses
USDA hardiness zones: 9-11.
Heat tolerant: Yes.
Drought tolerant: Yes.
Sun: Full sun to part shade.
Water once established: Monthly. Overwatering attracts aphids.
Soil: Well drained, low in organic material, pH 6.6-8.5 (neutral to alkaline). Do not fertilize.
Prune: In winter, cut overgrown clumps to their base to induce new growth.
Litter: Low.
Propagation: Seed.
Uses: Butterfly garden, xeric garden, butterfly caterpillar nursery.

This plant is a member of the Dogbane family (Apocynaceae). Another common name is Rush Milkweed. The blue to green stems provide a bit of color all year. This is a long blooming plant.

The best way to keep this plant from flowering is to fertilize it or water it more than once every two weeks. Being a desert plant, it should be in poor, unamended soil, and never fertilized. The soil should be very well draining, and seldom watered, because this plant can suffer from root rot in wet soil.

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Asclepias subulata: Desert Milkweed - flowers

Asclepias subulata: Desert Milkweed - with butterfly

Asclepias subulata: Desert Milkweed - seed pods

Asclepias subulata: Desert Milkweed

Latest update: July, 2019
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