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Boerhavia spp.

spiderlings

Nyctaginaceae Tropics and warm regions worldwide

Attracts Pollinators Drought Tolerant

Native to North America

SunFull Sun

WaterVery Low · drought-tolerant

HardinessZones 9–11

Overview

Boerhavia spp. is a genus of about 40 species in the four-o'clock family (Nyctaginaceae), made up of sprawling annual and perennial herbs native to tropical, subtropical, and warm temperate regions worldwide. Plants form low, spreading or trailing mats and tangles, with stems 1-3 ft (0.3-0.9 m) long that root at the nodes and often turn reddish in sun. The paired leaves are oval, 0.5-2.5 inches (1.3-6 cm) long, frequently with wavy margins and a paler, sometimes sticky underside. Tiny tubular flowers, only 0.1-0.2 inch (2-5 mm) across and pink, magenta, white, or greenish, open in airy branched clusters held on thread-like stalks, giving the spiderling its name. The small fruits are sticky and ribbed, clinging to fur, feathers, and clothing, which carries the seed widely. Members of the genus grow on disturbed ground, roadsides, and dry open soil, and several behave as weeds in farmland and gardens. Most are deep-rooted and drought-hardy, surviving long dry spells with little water.

Native Range

Native across the tropics, subtropics, and warm temperate zones of the Americas, Africa, Asia, and the Pacific, typically in dry, open, and disturbed habitats. Several species are widespread weeds that have spread far beyond their original ranges.

Suggested Uses

Used mainly in dry, informal, and naturalistic plantings on poor soils, and some species have a history of local food and medicinal use. The deep roots and drought tolerance suit hot, dry banks where little else grows. Because several species behave as weeds, the genus is kept out of irrigated beds and managed where it self-sows.

How to Identify

Recognized by low, sprawling reddish stems with paired oval leaves and by airy, much-branched clusters of tiny tubular pink to white flowers on thread-like stalks. The small ribbed fruits are sticky and cling to clothing and animal coats. The minute flowers in open spidery sprays and the sticky fruit separate Boerhavia spp. from the larger-flowered four-o'clocks Mirabilis spp. in the same family.

Appearance

Size & Dimensions

Height6" - 3'

Width/Spread1' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~20 weeks

Spring Summer Fall

Flowering continues over a long warm-season span, often from late spring through autumn (May-October) and year-round in frost-free climates. The flowers open for only part of the day and are pollinated by small insects. Sticky fruit follows quickly and ripens over much of the growing season.

Detailed Descriptions

Flower Description

Pink to white

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)

357912

Soil Types

sand loam rocky

Drainagedry

Water & Climate

Water Needs

Very Low

Frost Tolerance

tender

Time to Maturity

1 year

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow in full sun on dry, well-drained, even poor and sandy soil; the genus withstands heat, drought, and lean ground once established. Plants are frost-tender and behave as annuals where winters are cold, returning from seed or from deep roots in mild areas. Rich, moist soil produces lush, soft growth and heavier self-seeding. Most species need little or no water once rooted. The sticky fruit clings to clothing and animals and spreads plants into new ground. Pulling plants before the fruit ripens limits their spread as a weed.

Pruning

Little pruning is needed, as the plants are low and herbaceous; sprawling stems are trimmed back to keep them within bounds. Removing the plants before the sticky fruit sets limits self-seeding and the spread of seed on clothing and fur. Frost blackens and kills the top growth in cold climates.