Asperula spp.

Europe, the Mediterranean, western Asia, and Australia

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

SunFull Sun – Part Shade

HardinessZones 5–8

Overview

Asperula spp. is a genus of about 200 annual and perennial herbs in the madder family, found across Europe, the Mediterranean, western Asia, and Australia. Most are low, tufted or mat-forming plants 2-18 inches (5-45 cm) tall with slender stems bearing narrow leaves in whorls of four to eight, in the manner of bedstraws. Small tubular flowers with four spreading lobes, about 0.1-0.3 inch (3-8 mm) long, open in clusters in late spring and summer, white, pink, or pale blue depending on species. Alpine species such as A. arcadiensis form silver-haired cushions with pink flowers, while A. tinctoria, dyer's woodruff, has white flowers and roots once used for red dye. Foliage of the fragrant species smells of fresh hay when dried, from coumarin in the leaves. Mat-forming species spread by slender rhizomes to form low patches, and some sprawl loosely among neighbours. Cushion alpines are short-lived in wet or heavy soil and may rot over winter.

Native Range

Native to Europe, the Mediterranean region, western and central Asia, and Australia. Grows on rocky alpine slopes, dry grassland, scrub, and open woodland, with cushion species on stony mountain ground and woodland species in shadier sites.

Suggested Uses

Grown in rock gardens, troughs, raised alpine beds, and gravel gardens, with cushion species spaced 6-10 inches (15-25 cm) apart. Woodland species are used as low groundcover in dappled shade. Cushion alpines grow in containers of at least 1 gallon (4 L) with a gritty, free-draining mix.

How to Identify

Recognized by slender stems carrying whorls of four to eight narrow leaves and clusters of small tubular four-lobed flowers in white, pink, or pale blue. The arrangement resembles bedstraw, Galium spp., but Asperula flowers have a longer tube. Cushion alpines such as A. arcadiensis have silver-haired foliage and pink flowers, separating them from the looser, green-leaved woodland species.

Appearance

Size & Dimensions

Height2" - 1'6"

Width/Spread6" - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~4 weeks

Spring Summer

Clusters of small flowers open from late spring into summer, about May through August. Bloom lasts 3-6 weeks. Alpine species flower earlier and more briefly than woodland species. Cool weather and adequate moisture lengthen the display.

Detailed Descriptions

Flower Description

white, pink, or pale blue

Foliage Description

green to silver-haired

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

loam sand chalk rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Cushion and alpine species grow in full sun and gritty, sharply drained soil, while woodland species take part shade and moister ground. Wet, heavy soil rots the silver-haired alpines, especially over winter. Plants are watered sparingly once established, as most tolerate dry conditions. Few pests trouble the foliage. Mat-forming species spread by rhizome and are divided in spring to renew them or limit their spread. Foliage of fragrant species contains coumarin, which scents the dried leaves and can harm pets in large amounts.

Pruning

Plants are sheared lightly after flowering to keep cushions and mats compact. Spent stems of taller species are cut back in autumn. Spreading rhizomatous species are divided or edged in spring to control their extent.

Pruning Schedule

summerfall