Obsidian Coral Bells

Overview

• Botanical Name: Heuchera ‘Obsidian’ (‘Obsidian Coral Bells’) 

• Common Name: Obsidian Coral Bells

• Key Features: Deep burgundy/black foliage that retains its dark colour, with delicate light‑green bell‑shaped flowers in summer. 

• Habit: Low growing mound; foliage forms a compact clump. 

• Hardiness / Suitability: While exact zone for this cultivar isn’t always specified, Heuchera in general are hardy and the species is noted for zones around 4‑9 with some cultivars doing in colder climates. 

Light & Site Requirements

• Light: Prefers part shade (especially in hotter climates) but darker‑leaf varieties like ‘Obsidian’ can tolerate more sun (morning sun + afternoon shade recommended) if kept well‑watered. 

• Soil: Well‑drained, rich in organic matter. Avoid areas where soil stays soggy or crowns stay wet. 

• Choice of site: Because of its dark leaves, it works especially well for contrast in mixed borders or shady edges.

Watering & Maintenance

• Watering: After planting, keep soil evenly moist until the plant is established. Once established, Heuchera are fairly tolerant of moderate dryness but appreciate consistent moisture (but not soggy). 

• Mulching: A light mulch helps conserve moisture and keeps roots cool, especially in warm conditions. But avoid piling mulch against the crown.

• Pruning / Clean‑up: In early spring or late winter, remove any dead or damaged leaves. After flowering, you can trim off spent flower stalks to keep the plant tidy. 

• Division: Every few years (perhaps 3‑4 years) consider dividing the clump to maintain vigor and prevent overcrowding. 

Cold Climate Considerations

• Even though ‘Obsidian’ may not be explicitly rated for Zone 3 in all sources, the generic Heuchera guideline indicates many cultivars can manage colder zones with proper site conditions. 

• For colder climates: ensure excellent drainage (especially important in winter when snow melts), avoid low spots where water lingers, and locate where crown won’t be repeatedly frozen/thawed.

• Consider a light mulch after first heavy frost to protect the crown, especially if site is exposed.

• Because the foliage remains attractive, even if top growth slows, good site selection ensures year‑round interest.

Photo from Wilson Nurseries