Comandra spp.

bastard toadflax

Santalaceae

North America and southeastern Europe

Attracts Pollinators Drought Tolerant

Native to North America

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 3–8

Overview

Comandra spp. is a small genus of hemiparasitic perennial herbs in the sandalwood family, Santalaceae, with species across North America and one in southeastern Europe. Plants grow 4-16 inches (10-40 cm) tall from slender, spreading rhizomes, with erect, leafy stems bearing alternate, stalkless, somewhat fleshy leaves. The small flowers lack true petals; instead five white to greenish, petal-like sepal lobes spread in a star, gathered in flat-topped terminal clusters in late spring and summer. Each flower develops into a small, dry, one-seeded fruit crowned by the remains of the flower. Though green and leafy, Comandra spp. is a root hemiparasite: its roots form attachments called haustoria that tap the roots of many neighbouring plants for water and minerals while it still makes its own sugars. It grows in dry prairies, sandy barrens, and open woodland, often spreading underground into patches. The North American C. umbellata is an alternate host for comandra blister rust, a fungal disease of hard pines, which limits its planting near commercial pine. Plants are difficult to cultivate because of their need for host roots.

Native Range

Comandra spp. is native to the Northern Hemisphere, with the widespread C. umbellata ranging across most of North America and a separate species in southeastern Europe and Asia Minor. It grows in dry, open habitats such as prairies, sandy barrens, rocky slopes, and the floor of open woodland.

Suggested Uses

Comandra spp. is grown mainly in prairie restoration and native plant collections rather than ornamental gardens, where it weaves through grassland as part of a diverse plant community. The flowers draw small native bees and other insects. Its role as an alternate host for comandra blister rust makes it unsuited to planting near hard pines.

How to Identify

Look for a low, erect perennial with alternate, stalkless, slightly fleshy leaves and flat-topped clusters of small star-shaped flowers whose five white to greenish lobes are petal-like sepals rather than true petals. The dry, one-seeded fruit is topped by the persistent flower remains. Spreading rhizomes and a habit of growing intermingled with other plants, whose roots it taps, help identify the genus.

Appearance

Size & Dimensions

Height4" - 1'4"

Width/Spread8" - 2'

Colors

Flower Colors

white

green

Foliage Colors

green

Bloom Information

Bloom Period

Spring Summer

Flowering occurs in late spring and summer, generally May to July, with the small white star-shaped flowers opening in flat clusters over a few weeks. They are pollinated by small bees, flies, and other insects. Dry one-seeded fruits ripen later in summer.

Detailed Descriptions

Flower Description

white to greenish

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-10 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 - 7.5(Neutral)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

3-5 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Comandra spp. grows in full sun to light shade on dry, sandy, or rocky, sharply drained soil and tolerates lean, low-nutrient ground. As a root hemiparasite it depends on the roots of neighbouring host plants for part of its water and minerals, which makes it slow and unreliable to establish in cultivation. Plants are hardy through much of the cold-temperate range, into USDA zone 3, and spread by rhizomes once settled. They withstand drought, heat, and poor soil but do not persist in rich, wet, or heavily shaded sites. Growing plants among suitable grass or shrub hosts improves survival. The genus is rarely grown outside native plantings and restoration.

Pruning

No pruning is needed for this low, spreading perennial. Dead stems can be cleared in autumn as they die back to the rhizome. Plants are left undisturbed, since the parasitic roots make division and transplanting difficult.