Bunium spp.

earthnut

Apiaceae

Europe, North Africa, and temperate Asia

Attracts Pollinators Drought Tolerant Fragrant (moderate)Container Friendly

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 5–9

Overview

Bunium spp. is a genus of about 40 to 50 perennial herbs in the carrot family (Apiaceae), native to Europe, North Africa, and temperate Asia, several of which grow from an edible rounded tuber. The plants reach 12 to 30 inches (30 to 75 cm) tall, with finely divided, ferny leaves and branched stems topped by flat, open umbels of small white flowers. Familiar species include B. bulbocastanum, the great pignut or earthnut, whose chestnut-flavoured tuber has long been eaten, and B. persicum, the source of the spice known as black cumin or zira, whose dark, curved seeds flavour South Asian and Central Asian dishes. Bunium spp. grows in grassland, scrub, rocky slopes, and field margins, usually on well-drained, limy soils. Plants are slow to establish from seed and take two or more years to flower and form a usable tuber. The top growth dies back after the seed ripens, and the tuber rests below ground until the next season.

Native Range

Bunium spp. is native to Europe, North Africa, and temperate Asia, with a centre of diversity in the Mediterranean and western Asia. It grows in dry grassland, scrub, and rocky ground, often on chalky or stony soils.

Suggested Uses

Grown in herb gardens, edible landscapes, and dry sunny borders for its aromatic seeds and edible tuber, and in naturalistic grassland mixes. B. persicum is cultivated as the black cumin spice, while B. bulbocastanum is grown for its chestnut-like tuber. Spacing of 8 to 12 inches (20 to 30 cm) suits a clump or row.

How to Identify

Identify Bunium spp. by its finely divided, ferny foliage, flat umbels of small white flowers, and a rounded underground tuber at the stem base. The seeds are small, ridged, and aromatic. Its edible tuber and slender, much-divided leaves separate it from larger umbellifers such as cow parsley, and the spice species are known by their dark, strongly scented seeds.

Appearance

Size & Dimensions

Height1' - 2'6"

Width/Spread8" - 1'4"

Reaches mature size in approximately 2 years

Colors

Flower Colors

white

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~4 weeks

Summer

Flowering occurs in summer, mainly June to August, with flat white umbels held above the ferny foliage. The flowers draw a range of small pollinating insects. Aromatic seeds ripen in late summer and the top growth then dies back.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-10 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

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Bunium spp. grows in full sun on light, well-drained soils with a pH of 6.0 to 7.5, tolerating chalk, sand, and loam. Established plants withstand drought, drawing on the underground tuber through dry spells and winter dormancy. Seed is slow and erratic to germinate, often needing a cold period, and plants take two or more years to flower and bulk up a tuber. Wet, heavy soils cause the tuber to rot. Little feeding is needed on reasonable ground.

Pruning

Cut back the dying top growth once the seed has ripened and the foliage yellows. Seed heads can be removed earlier to harvest the spice or to limit self-sowing. The resting tuber needs no other attention.