Funastrum heterophyllum (Hartweg's climbing milkweed)

Funastrum, Genus, spp., Multiple species,

Genus
Multiple species

Twinevine

Apocynaceae

Americas: southern US, Mexico, Caribbean, Central and South America

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

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 8–11

Overview

Funastrum is a genus of about a dozen species of twining, milky-sapped vines in the dogbane family (Apocynaceae, subfamily Asclepiadoideae), native to warm parts of the Americas from the southern United States through Mexico and the Caribbean to South America. Plants twine over other vegetation and fences with slender stems to 3-10 feet (0.9-3 m) long, exuding a white latex when cut. The opposite leaves are narrow to heart-shaped depending on the species. Small, star-shaped flowers about 0.3-0.5 inch (8-12 mm) across are clustered in rounded, umbel-like heads and come in white, cream, pink, or pale purple, often sweetly scented. As in milkweeds, fertilized flowers form paired, spindle-shaped seed pods (follicles) that split to release flat seeds with silky tufts carried on the wind. Funastrum grows in deserts, scrub, riverbanks, and disturbed ground, and serves as a larval host for monarch and queen butterflies. The milky sap can irritate skin and is toxic if eaten, and the vines can twine aggressively over nearby plants.

Native Range

Funastrum is native to the Americas, ranging from the southwestern and southern United States through Mexico, Central America, and the Caribbean into South America. Several species are North American natives of deserts, grasslands, and riverbanks.

Suggested Uses

Funastrum is grown in native, pollinator, and butterfly gardens as a larval host for monarch and queen butterflies and a nectar source for many insects. It is planted on fences, trellises, and arbors in warm-climate and desert gardens. It also features in habitat restoration of arid and riparian areas within its native range.

How to Identify

Recognized by slender twining stems that ooze white latex when broken, opposite leaves, and rounded clusters of small, star-shaped, five-lobed flowers in white to pale purple. Paired spindle-shaped seed pods that split to release silky-tufted seeds confirm its place among the milkweeds. The twining habit separates Funastrum from upright milkweeds in the related genus Asclepias.

Appearance

Size & Dimensions

Height3' - 10'

Width/Spread2' - 6'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~20 weeks

Flowers: April–September

Spring Summer Fall

Flowering occurs from spring through autumn in warm climates, with a peak in the warmer months. The clustered star-shaped flowers are often sweetly scented and draw bees, wasps, butterflies, and other insects. Spindle-shaped pods develop afterward and release wind-borne seeds.

Detailed Descriptions

Flower Description

white to pale purple

Foliage Description

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 Range6.0 - 8.0 (Neutral to alkaline)

3579

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Funastrum grows in full sun in free-draining sandy, gravelly, or loamy soil and tolerates heat and drought once established. It climbs by twining and needs a fence, trellis, or host plant to ascend, otherwise sprawling over the ground. Plants are raised from seed or cuttings and grow quickly in warm conditions. Established plants need little water in mild and arid climates. The stems can twine over and smother small neighboring plants, so they are given room or a dedicated support. The milky sap is an irritant and is toxic if eaten.

Pruning

Stems are cut back in late winter or after flowering to control spread and remove tangled or dead growth. Plants resprout from the base after hard cutting. Trimming is done with care, as the cut stems release irritant latex.