What hardiness zones is Heuchera × 'Obsidian' suitable for?

Heuchera × 'Obsidian' is a heuchera with near-black to very dark purple glossy smooth rounded leaves that maintain their dark color through summer heat without fading. Plants grow 8–12 inches (20–30 cm) tall as a foliage mound. The cultivar name references obsidian, the volcanic glass that is jet-black and glossy — the leaf color and surface sheen match this description. The near-black color absorbs light rather than reflecting it, making the plant function as a dark anchor point in garden design that sets off lighter-colored neighbors. The smooth, glossy leaf surface (without the ruffling or lobing of some heucheras) has a simple, modern appearance suited to contemporary garden design. Tiny cream-white flowers on dark stems appear from May through July — the light flowers against the dark foliage create a strong contrast. Bred by Terra Nova Nurseries (Canby, Oregon), 'Obsidian' was among the first heucheras to achieve near-black coloring that held through the season. The H. villosa genetics in its background contribute heat tolerance. In deep shade, the near-black color may appear very dark purple rather than true black; moderate light deepens the effect. Deer avoid the foliage.

Native Range

Heuchera × 'Obsidian' is a garden hybrid bred by Terra Nova Nurseries in Canby, Oregon.

Suggested Uses

Used as a dark foliage anchor in shade borders, containers of 3 gallons (11 L) or more, and mixed plantings. The near-black color sets off chartreuse, silver, gold, and bright-flowered companions. Suited to modern and minimalist garden designs where the simple leaf shape and glossy dark surface match a clean aesthetic.

How to Identify

Identified by near-black to very dark purple glossy smooth rounded foliage that maintains its dark color without summer fading. The smooth, glossy leaf surface (not ruffled) and simple rounded leaf shape are characteristic. Cream-white flowers on dark stems create a contrast display in late spring.

Appearance

Size & Dimensions

Height8" - 2'

Width/Spread1'2" - 1'6"

Reaches mature size in approximately 2 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Spring Summer

Flowering from May through July, approximately 6 weeks. Cream-white flowers on dark stems contrast with the near-black foliage.

Detailed Descriptions

Flower Description

Tiny cream-white on dark stems

Foliage Description

Near-black to very dark purple, glossy, smooth, rounded

Growing Conditions

Sun Requirements

Partial Shade Full Sun

Requires 3-6 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 Range5.5 - 7.0(Neutral)

357912

Soil Types

loam

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plant in partial shade to partial sun with 3–6 hours of light. Moderate light deepens the black color; deep shade may lighten it to dark purple. Moist, well-drained, humus-rich soil. Spent flower stalks can be removed. Tattered foliage can be cleaned up in early spring. Frost-heaved crowns can be pushed back into the soil.

Pruning

Spent flower stalks can be removed. Tattered leaves can be cleaned up in early spring. Frost-heaved crowns can be pushed back into the soil.

Pruning Schedule

early spring

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 3 gallons

⚠️ Toxicity Warning

Non-toxic