Asclepias amplexicaulis (clasping milkweed)

Mason Brock (Masebrock), no rights reserved (CC0) · Wikimedia Commons

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Asclepias amplexicaulis

clasping milkweed

Apocynaceae Eastern and central North America

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Fragrant (light)

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 3–9

Overview

Asclepias amplexicaulis is a herbaceous perennial reaching 12-36 inches (30-90 cm) tall, usually with a single unbranched stem. The opposite, oblong leaves are 3-6 inches (8-15 cm) long, blue-green, smooth, and waxy, with strongly wavy margins and bases that clasp the stem. A single rounded flower cluster sits at the top of the stem, holding many small flowers in shades of rose, green, and pink, opening in late spring to early summer. Flowers are followed by erect, spindle-shaped pods 4-6 inches (10-15 cm) long that split to release seeds with silky white hairs. The stem and leaves exude milky sap when cut. Growth is slow, from a deep taproot that makes established plants difficult to move. The plant tolerates poor, dry soils but is slow to establish and may not flower in its first two years.

Native Range

Native to eastern and central North America, from New England and Ontario west to Nebraska and south to Florida and Texas. Grows in dry, open, sandy or rocky ground including prairies, fields, open woods, and roadsides.

Suggested Uses

Planted in dry meadows, prairie plantings, and native pollinator gardens at 12-18 inch (30-45 cm) spacing on lean, well-drained soil. Suited to sunny, dry sites where richer-soil milkweeds struggle. Grown to support monarch butterflies and other pollinators.

How to Identify

Identified by blue-green, waxy leaves with distinctly wavy margins and clasping bases, and a single rounded flower cluster at the stem tip. Flowers combine rose, pink, and green tones. The wavy clasping leaves separate it from Asclepias syriaca, which has broad flat leaves on short stalks and multiple flower clusters.

Appearance

Size & Dimensions

Height1' - 3'

Width/Spread1' - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Spring Summer

Flowers from late spring into early summer, mainly May through June across most of its range. A single cluster blooms over about three weeks. Bloom is sparse on young plants and increases as the taproot matures over several years.

Detailed Descriptions

Flower Description

rose, pink, and green

Foliage Description

blue-green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

sand rocky loam

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun in dry, sandy or rocky, sharply drained soil. Water lightly until established, then withhold irrigation, as the deep taproot tolerates drought and rots in wet soil. The plant resents disturbance, and the deep taproot does not transplant well once established. It serves as a larval host for monarch butterflies, whose caterpillars feed on the foliage. Aphids gather on stems and buds in summer. The milky sap is mildly toxic to people and livestock if eaten in quantity.

Pruning

No routine pruning is needed. Spent stems can be cut to the ground in late fall or left standing through winter for seed dispersal and insect shelter. Removing pods before they split prevents self-seeding.

Pruning Schedule

fall