Crevice alumroot – info, planting, care and tips

Crevice alumroot (Heuchera micrantha)
Crevice alumroot (Heuchera micrantha)

There are numerous decorative cultivars of the crevice alumroot. Here are tips for planting and care of the flower.

Profile of crevice alumroot:

Scientific name: Heuchera micrantha

Plant family: saxifrage family (Saxifragaceae)

Other names: –

Sowing time: spring

Planting time: spring or autumn

Flowering period: June to July

Location: partial shade, no direct sun

Soil quality: sandy to loamy, nutrient rich, humus rich

These information are for temperate climate!

Use in: flower beds, group planting, planters, underplanting, borders, flower garden, courtyard, rhododendron garden, potted garden, forest garden

Winter hardiness: hardy, USDA Plant Hardiness Zones: 5 (-26 °C / -15 °F)

Bee and insect friendly: Yes

Plant characteristics and classification of crevice alumroot

Plant order, origin and occurrence of crevice alumroot

Heuchera micrantha, the crevice alumroot, is a wild species from western North America. The pure species is hardly in cultivation, but it played an important role in the cultivation of today’s garden varieties of the alumroot. The crevice alumroot belongs to the saxifrage family (Saxifragaceae).

Characteristics of crevice alumroot


Heuchera micrantha has a decorative foliage. The basal leaf rosettes reach heights of 30 to 40 centimeters (12 to 16 in). The flower panicles rise above this on wiry stems and reach a height of 60 centimeters (24 in). The perennial pushes its rhizomes upwards from below. At the natural location, the forest plant repeatedly lifts itself out of the leafy layer from which it is covered every autumn gardening jargon.


The lobed leaves are round to heart-shaped, mostly lobed and naturally silver-gray. However, the varieties show a wide variety of leaf colors, also by cross-breeding with other Heuchera species. In mild winters, the old foliage remains vital until the next spring. Only then is it covered by the newly emerging leaves and dies back over time.


From June to August, the crevice alumroots produce countless small, white flower bells in loose umbrella-like clusters, which develop a charming shimmering effect. If the morning dew stays on the delicate flowers, a glitter effect results in the sunlight.


The seed heads turn pinkish-bronze in ‘Palace Purple’, yellowish in green and yellow-leaved varieties, and consist of small capsule fruits.

Crevice alumroot – cultivation and care


Heuchera micrantha naturally prefers shady locations, preferably under larger trees with tolerant roots. Although the dark-leaved varieties of the crevice alumroot thrive in sun to partial shade, it is better to choose places less exposed to the sun. This also prevents damage to the leaf in winter in severe bald frosts.


The soil should be rich in humus and not too dry. The crevice alumroot grows lush, the more nutrient-rich and humus the subsoil is.

Planting crevice alumroot

Crevice alumroot needs consistent soil moisture after planting. Because of the higher rainfall, the spring and autumn months are more suitable as a planting time than the summer months. If you want to plant it in a pot or balcony box, place the perennial with the rhizomes a little deeper than it was previously in the pot. As a result, it grows wider.


Heuchera micrantha in planters must be watered regularly. And you should also water in the bed if the natural rainfall is insufficient. Winter wetness, on the other hand, is particularly problematic for silver bells in the pot. The roots will rot if it is too damp. Move potted plants under a roof overhang in winter and water them if necessary.


In autumn, you can fill in humus between the heuchera that have lifted themselves out of the ground. If you do not want to divide the perennials, simply filling them with humus will revitalize the plants.


Faded parts are usually cut off with scissors in favor of the foliage effect. Leaves that have become ugly are also cut back, especially after winter.


Alumroots push themselves further out of the earth with every year and with time they become bald from the center. You can remedy this by dividing. Take the entire plant out of the soil. You can carefully tear off rhizomes that have already formed roots and insert the pieces deeper again. Only the upper, leafy part should look out of the earth. The ideal time for this is between August and September. The rejuvenation also works in spring, for example, when you want to regroup crevice alumroots that have lifted themselves out of the pot.


Crevice alumroot can be propagated by sowing. Even seedlings of the variety ‘Palace Purple’ consistently produce red-leaved plants, but turn green more easily in the course of summer. The shiny dark tone of the original type is only obtained with vegetative propagation, for example, by simply dividing the perennials or rooting cuttings in a seed tray.

Diseases and pests

Black weevils can become a problem, as they cause typical herbivore damage on the leaf edges. A nematode vaccination in spring helps against the larvae that live underground. Snails, on the other hand, rarely attack crevice alumroot, they prefer the hostas, with which the perennials are often planted together. Fungal diseases are rare in all alumroots. If brown spots appear on the leaves, it is usually sunburn caused by drought.


The evergreen foliage of the planted crevice alumroot suffers from bald frosts in winter. With a cover made of brushwood you can protect the plants from damage to the leaves. Crevice alumroot s are hardy and will definitely sprout again in spring, even if the old leaves have frozen. Winter protection for the perennials is therefore not essential for survival.

Use in the garden

The crevice alumroot is not a ground cover in the strict sense of the word, it grows too cluster-like for that and would have to be set very closely to cover the surface well. But it is perfect as a foliage plant in semi-shady woodland, as an evergreen border and companion. The varieties can be mixed very nicely. In shady areas, also between rhododendrons and azaleas, Heuchera micrantha varieties go well with hostas, lenten roses, Alpine barrenwort as well as grasses and ferns. You can also use it to highlight treasures such as blue corydalis (Corydalis elata) and monkey grass (Liriope muscari,). The decorative foliage, especially varieties with a dark-foliage, sets exciting contrast points in a planting and structures it. As structural plants in planters, alumroots are particularly popular for autumn arrangements.


As we now know, ‘Palace Purple’ is not a direct descendant of the crevice alumroot, but is still known as Heuchera micrantha in nurseries. It impresses with its dark foliage, which, depending on the incidence of light, shimmers deep wine red, bronze or chocolate brown. The flowers are cream-colored.

An excellent cultivation from ‘Palace Purple’ seedlings is ‘Molly Bush’. The fragrant white panicles of flowers form a beautiful contrast to the deep purple-violet leaves.

The very vigorous ‘Rachel’ is also comparable to ‘Palace Purple’, but flowers pink.

‘Plum Pudding’ not only has very intense black-red foliage, the top of the leaves is attractively veined with silver. It blooms whitish pink.

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