Heuchera: location, pruning & the most beautiful varieties

Heuchera, despite its comparatively short flowering period, delights us with its striking leaves. If you provide a suitable location for alumroot, it will decorate gardens into the winter.

Alumroot is also known to many gardeners by its generic name Heuchera. The leafy ornamental perennial is comparatively undemanding and versatile in the garden or in planters. There are now numerous varieties of alumroot to choose from. We have collected a selection of the most beautiful heuchera species and their varieties. We also explain what the optimal locations look like and how to ideally care for the alumroot.

Heuchera: flowering period, characteristics and origin

The genus Heuchera originated in the North American continent and is found primarily in rock crevices and coastal forests. Heuchera belongs to the saxifrage family (Saxifragaceae) and holds around 50 different species, for example, the smallflower alumroot (Heuchera micrantha) and the coral bells (Heuchera sanguinea). You may also know the alumroot as the silver bellflower. The leaves resemble maple foliage and can have different colours and markings depending on the variety. The leaf margins are toothed to lobed.

The flowering period of alumroot, like its appearance, depends on the variety. Most heuchera cultivars bloom from May to July, although cultivars such as hairy alumroot (Heuchera villosa var. macrorrhizza) only show their flowers in autumn. However, the alumroot owes its German name (Purpurglöckchen) not to its striking leaves, but to its bell-like flowerheads. The flower panicles rise up amid the colourful leaves and reach a growth height of 40 to 100 cm, depending on the variety. The flower of heuchera can show different colours, from greenish-white to pink and dark red.

The herbaceous alumroot is perennial and evergreen, or wintergreen, decorating the garden year-around and displaying a full set of new leaves in spring. In addition, alumroot is equally popular with butterflies and bees.

The most beautiful heuchera varieties and species

Heuchera offers an amazing variety of species and varieties. Making a decision is not easy – here we show you a pretty selection.

Heuchera micrantha

This species appears rather inconspicuous in its natural form, but serves as an important parent species of several cultivars and hybrids. In June to July, the greenish-white to pink flowers rise up to 100 cm in height on panicles. Without the flowerheads Heuchera micrantha reaches a height of 40 cm. It prefers a humus-rich, fresh and loose soil in a sheltered, semi-shady spot. Overall, the species is hardy and quite undemanding, provided that the place is protected from waterlogging and deep frosts in the soil. Ensure a planting distance of approximately 20 to 30 cm in small groups of 5 to a maximum of 10 plants per m².

• ‘Shanghai‘ stands out with dark purple leaves. From May to August, the beige to soft purple flowers appear. This variety survives – 15 °C, although frost damage may occur in unprotected locations. ‘Shanghai’ enjoys an off-sun to sunny location.

• ‘Paris’ blooms intense pink from June to July. The green-coloured leaves have a silvery pattern that contrasts beautifully with the richly coloured flowers. The soil should be fresh, permeable and rich in nutrients. For this variety, choose a sheltered spot in partial shade. Temperatures down to – 15 °C are no problem.

• ‘Obsidian’ has striking black-red, silky shimmering foliage, which can grow up to 50 cm high. The snow-white flowers appear from July to August. For this variety, ensure a larger planting distance of about 30-40 cm. Obsidian’ can easily withstand temperatures of – 22 °C.

Heuchera villosa

The heuchera species is equally considered an important parent species of some popular varieties. The wild form is characterised by strong green and particularly patterned leaves. When in bloom, it reaches a height of 70 cm. As with other heuchera species, prolonged ground frosts because damage to the plant, as does waterlogging, although Heuchera villosa is one of the insensitive species and can survive temperatures as low as – 15 °C.

• ‘Berry Smoothie‘ delights us with its purple, silvery leaves. The white flowers appear from June to July, although this variety is lazy in flowering overall. The popularity of this variety is due to its longevity and endurance. A planting distance of 20 to 30 cm offers ‘Berry Smoothie’ sufficient space.

• ‘Caramel‘ is equally among the lazy-flowering heuchera varieties, but this does not affect its ornamental value. The large, caramel-coloured leaves with dark undersides shine intensely, especially amid green-leaved neighbours. ‘Caramel’ blooms from June to August and has good heat tolerance. Plant this variety with a spacing of 35 cm, that is, about 8 specimens per m².

Heuchera sanguinea

In its wild form Heuchera sanguinea is rather inconspicuous, but known for the variety ‘firefly’. In total, these species grow up to 40 cm in height, and even up to 100 cm in flowering state. The original variety grows preferably on a coarse-grained, humus-rich limestone soil.

• ‘Firefly’ belongs to the standard assortment with its purple flowers. The variety blooms from June to July and tolerates a sunny to semi-shady location. Choose a maximum of 10 plants per m² to provide enough space. The same soil preferences apply – fresh, well-drained and nutrient-rich.

Tip: The popular ornamental perennial Heucherella, also known as foamy bells, is a cross between Heuchera and Tiarella (foam flower). The hybrids combine the beautiful leaves of the Heuchera and the attractive flowers of the foam flower.

Planting heuchera: location and procedure

Select an alumroot species that suits your site conditions – see species-specific site preferences in the species and cultivar descriptions above. In general, choose a sunny to semi-shady place that provides protection from frosts.

Tip: Go by leaf colour – the darker the leaves, the sunnier the location should be. Otherwise, the green colour of these varieties may fade. Conversely, species and varieties with light-coloured leaves should not be exposed to strong sunlight.

For most species and varieties, permeable and loose soil and constant soil moisture are important. Drought is tolerated only briefly – too much soil moisture favours diseases and pest infestations. Rust fungi and black vine weevils occur in heuchera species especially in overly moist locations, while slugs completely disregard alumroot.

Once you have found a suitable location, you can plant alumroot almost all year around. The ground should not be frozen, so the months from March to October are suitable. In small groups of 3 to 10 plants and a planting distance of 30 to 45 cm, depending on the species and variety, alumroot has enough space to grow. Prepare the soil by loosening it and removing weeds.

Most alumroot species require nutrient-rich soil. Extremely sandy soils should be mixed with a humus-rich soil, otherwise fertilising in the spring is sufficient. For example, our Plantura Flower Food could provide Heuchera with the nutrients it needs. It has a long-term effect of at least 3 months. Applying fertiliser in the spring will thus allow the alumroot to get through the year in good health. If your soil is very clayey and therefore prone to high soil moisture, mix in a generous amount of 50% sand to thin it out.

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Use the rootstock as a guide for planting depth. Alumroot should be planted low enough so that the leaf rosette rests level on the ground. After planting, you may water the Heuchera generously.

Heuchera species make a superb display in window boxes or pots. Alumroot grow up to 30-40 cm in width. Accordingly, the pot should be at least 30 cm in diameter. A water drainage hole and a drainage layer of gravel or chippings prevents waterlogging, which must be avoided at all costs. It is best to use a substrate rich in humus, such as our Plantura Organic Flower Compost. It is rich in nutrients and provides the necessary permeability due to the presence of expanded clay. In addition, it is made of 100% natural raw materials, which means that less CO₂ is released during production. A drainage layer is recommended.

The right care

If the conditions for planting were observed, alumroot care is not particularly time-consuming.

Watering and fertilising

Water the alumroot tactfully – it tolerates short dry periods better than constant moisture. In general, the soil should not be too wet, but also not completely dry. In the flower bed, annual fertilisation of alumroot with a primarily organic flower fertiliser or some fresh compost is possible. For best results, add fertiliser in spring. For plants cultivated in tubs, the use of a slow-release fertiliser is a must, but no more than once in the spring and once in late summer.

Pruning alumroot

Regular cutting out of the wilted leaves not only beautifies the appearance of Heuchera, but leads to more strength for the remaining leaves. Cut the alumroot for care in the spring. Make sure that the cutting height is about 10 cm so as not to damage the lower part of the plant. Avoid pruning in the autumn, as the foliage serves as winter protection and adds an appealing touch of decoration even in winter.

More important than cutting the leaves is a division of the rootstock every 2 to 3 years. Alumroot forms rhizomes underground. These store nutrients, but also serve for vegetative propagation. Nearby offshoots compete with the mother plant for light, water, and nutrients, causing the entire bunch to lose vitality over time. How to successfully divide Heuchera, we explain later in the article.

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Is alumroot hardy?

Alumroot plants are hardy as long as they are planted in a protected location. They easily survive temperatures as low as – 22 °C in suitable locations. To provide your alumroom with enough nutrients for the coming spring and thus for their new shoots, you can prepare the Heuchera for winter with a foliage cover. Place alumroot cultivated in tubs in a protected but not frost-free place, as they need a cold period to resprout in the spring.

Propagating Heuchera

The simplest and most common way to propagate Heuchera and help it grow again is by division, as mentioned above. To do this, carefully dig up the plant and divide the rhizomes into sections, each with a terminal bud. This can be done using a simple pair of rose secateurs. The newly obtained pieces can then be planted, leaving a sufficient distance between each specimen. Water the newly planted rhizomes well and care for them as described.

is alumroot poisonous?

Alumroot is not poisonous, neither for us humans nor for animals. You can safely plant the colourful Heuchera in the garden and enjoy its beauty.