Give your gardens the look of black lava with 'Obsidian' coral bells.
Love dark leaves? Then add Heuchera ‘Obsidian’ to your must-have list. This deep-toned coral bells has become the black standard when it comes heuchera foliage. Unlike some colorful coral bells, the dark hues of Obsidian don’t fade—even in full sun. One of the top five best-selling coral bells nationwide, Heuchera ‘Obsidian’ delivers foolproof color to any landscape.
Gardeners love coral bells for the stand-out foliage that adds reliable, season-long color to plant combinations. Heuchera ‘Obsidian’ is no different. The deep purple-black leaves deliver the darkest hue of all coral bells—year-round in regions with mild winters. The name is taken from the rock obsidian, a black stone formed when lava strikes water. Heuchera ‘Obsidian’ isn’t pure black, but it brings an almost-black shade to the garden.
Make the colors of Heuchera ‘Obsidian’ stand out even more by planting it with light colored plants. Pair it with Heuchera ‘Lime Rickey’ or Hosta ‘Lemon Lime’ for a neon sizzle. Or back it with dusty miller (Senecio cineraria) or Artemisia ‘Powis Castle’ for a white-black contrast. The dark leaves also pair well with pink bloomers, such as astilbe (Astilbe chinensis) or bleeding heart (Dicentra spectabilis).
Like all coral bells, Heuchera ‘Obsidian’ doesn’t grow huge. At maturity, you’ll have a mound of foliage that’s 10 inches tall by 16 inches wide. This is an ideal size for edging walkways or planting beds or for tucking into container gardens. Heuchera ‘Obsidian’ has the same salt tolerance as other coral bells, which makes it a go-to plant for edging walkways in cold winter regions. Tossing ice melt onto a sidewalk won’t make this beauty melt away, too.
Heuchera ‘Obsidian’ does have a tendency to heave out of soil during freeze-thaw cycles in northern regions. To help Heuchera ‘Obsidian’ survive frigid winters without heaving out of soil, add a layer of compost around the base of each plant in fall. The compost acts as a mulch, helping to insulate soil against temperature extremes. If your Heuchera ‘Obsidian’ does heave out of soil, the roots will have some protection from the compost. In spring, even though those same roots will start growing into compost, you’ll still want to tuck plants back into soil.
The flowers on Heuchera ‘Obsidian’ add eye-catching interest in spring. The bell-shaped blossoms float above the dark leaves on 24-inch-tall stems. Flower buds are a deep purple and open to reveal cream blooms. Be sure to clip flower stems after blossoms fade so plants direct their energy to pumping out more leaves.
As with all heuchera, you’ll need to dig and divide Heuchera ‘Obsidian’ every three to five years. You’ll know you waited too long to divide if your plants die out in the center. If that happens, dig plants up and cut away the dead center, saving the outer edges to replant as individual plants.