<i>Tiarella</i> and <i>Heucherella</i>: to plant and to grow

Description and botany

Tiarella and Heucherella both belong to family Saxifragaceae. They are cousins of Heucheras, with which these two perennial plants hybridise easily. Heucherella in fact results from hybridization between Heuchera and Tiarella: X Heucherella is a hybrid genus created in 1912 that combines best characteristics of both parents: decorative leaves and a dense, long flowering.

Genus Tiarella includes seven herbaceous, rootstock-bearing perennial plants with ornamental foliage native to cool woodland understoreys and stream banks in North America and Asia. In gardens, the most commonly seen species are Tiarella cordifolia, the heart-leaved Tiarella, which spreads by rootstocks without ever becoming invasive, and Tiarella wherryi, which has no stolons and a slower growth habit.

About thirty Heucherella varieties exist today, not counting new cultivars that appear each year.

Most Tiarellas and Heucherellas have a mat-forming habit. Some varieties (‘Tiarella Running Tiger‘) spread rapidly by means of leafy stolons that root like strawberry runners, producing new plants until forming large groundcover mats 10 to 90 cm high and equally wide at maturity.

Smallest varieties measure under 20 cm high in leaves, while larger cultivars reach at least 50 cm in height. Some, such as ‘Heucherella Redstone Falls‘, produce gracefully trailing stolons.

Tiarella wherryi, or Wherry Tiarella, is distinguished by a upright habit and forms clumps that are broader than tall, not exceeding 45 cm in height at maturity for a little more in width.

Tiarellas and their hybrids, the Heucherellas, belong to group of perennial plants noted for very decorative leaves with incredibly varied colours and textures. However, it is not always easy to tell these two plants apart because they are so similar. Differences occur between genera and among cultivars.

Some Tiarella leaves: T. ‘Appalachian Trail’, T. polyphylla and T. cordifolia ‘Mint Chocolate’

From a thick stem emerge in spring rosettes of evergreen to semi-evergreen leaves depending on winter severity. Basal leaves are ovate, heart-shaped or rounded and measure about 5 to 15 cm long. Leaves are simple or divided into 3 to 7 lobes of varying depth or palmate with a dentate margin and sometimes long-petiolate, resembling maple leaves. Heucherella leaves, smaller but equally colourful as those of Heucheras, have same elegance as Tiarella leaves.

Very dissected, leaves display vivid, warm colours, solid, variegated or marbled that change slowly with temperature, often more colourful in spring and autumn.

Silky or glossy, from pale green to emerald green sometimes shaded with red or purplish bronze, they may show, depending on cultivar, a central macule or striking, strongly contrasted veins, often purple on a clear green lamina. Foliage often takes coppery autumn tones before turning a deep red that can cover almost entire leaf lamina as cold sets in.

Some Heucherella leaves: H. ‘Copper Cascade’, H. ‘Solar Eclipse’, H. ‘Tapestry’, H. ‘Stoplight’

New hybrids offer remarkable colour range from chartreuse green to golden or silvery, through apricot orange, coppery red, pink veined with purple or glossy black purple. During summer they may develop cinnamon, copper-orange, soft pink or ruby tones. Prominent venation often enhances leaf pattern beautifully.

In spring, slender pubescent stems, sometimes reddish-brown, emerge from this mass of small leaves. From April to August, sometimes into autumn for Heucherellas depending on climate, starry or bell-shaped tiny flowers 1 to 10 mm across grouped in airy panicles or in loose clusters open, sometimes held up to 50 cm above leaves, forming a frothy floral display. Stems are shorter on Tiarellas.

This pretty, mossy-cone flowering is mainly springtime, February to June for Tiarellas, summer and autumn for Heucherellas. But both flower abundantly.

These airy spikes are white, creamy-white or pink and later develop into shiny black capsule fruits.

They make excellent cut flowers for delicate, fresh bouquets.

Easy to grow and with good hardiness below -15°C, Tiarellas and Heucherellas are excellent perennials for shaded, cool parts of the garden, where they provide a very airy aspect from spring into summer.

They thrive in fresh to moist, well-drained soils. Both are shade to partial-shade perennial plants that dislike very hot exposures.

Tiarellas and Heucherellas are among best mat-forming perennial plants: indispensable in a shade garden for dressing the bases of trees and bushes, in beds, damp rockeries or shaded borders, or even in pots or containers sheltered from strong sun.

Tiarellas are used in herbal medicine for their tonic and diuretic properties.

Main species and varieties

Most popular

Our favourites

Tiarella cordifolia

Perfect spring flowering to cover large areas in cool soil.

• Flowering time May to July
• Height at maturity 20 cm

See the product sheet

Heucherella Sweet Tea

Vigorous variety with remarkable apricot-orange foliage taking on a copper-orange hue in summer. Perfect in perennial beds and borders. Also a good groundcover. Can also be grown in containers on the terrace.

• Flowering time June, July
• Height at maturity 60 cm

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Heucherella Stoplight

Yellow to tangy green leaves, puckered and marbled with reddish-brown. This excellent groundcover also performs well in pots.

• Flowering time June, July
• Height at maturity 40 cm

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Tiarella Running Tiger

New variety with dark green, brown-maculated foliage that spreads to form large groundcover tapetums. Also cascades gracefully from a wall or hanging basket.

• Flowering time May to August
• Height at maturity 30 cm

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Heucherella Golden Zebra

Sumptuous colour-changing leaves through the seasons topped by airy, early flowering. Covers soil in perennial beds, borders or containers.

• Flowering time June, July
• Height at maturity 40 cm

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Tiarella wherryi

Beautiful perennial for cool shade forming a low tuft. Ideal for ornamenting damp woodland understorey or cool rockeries.

• Flowering time June to August
• Height at maturity 30 cm

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Heucherella Brass Lantern

Recent selection, highly ornamental and vigorous, with copper and amber tones, olive green in winter. Suits semi-shade beds and colourful understorey settings.

• Flowering time July to September
• Height at maturity 35 cm

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Heucherella Redstone Falls

First stoloniferous heucherella to bear copper-red leaves! Heucherellas of the 'Falls' series cascade. Ideal installed at the edge of a wall or in a hanging basket.

• Flowering time June, July
• Height at maturity 30 cm

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Tiarella Ninja

Long flowering and attractive, very persistent dark foliage that lasts into autumn. Perfect for covering large areas.

• Flowering time May to July
• Height at maturity 30 cm

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Heucherella Copper Cascade

A riot of colour for this new variety! Highly appreciated in hanging baskets or containers.

• Flowering time July, August
• Height at maturity 30 cm

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Tiarella Sugar and Spice

Early flowering. Chic and graphic for spring compositions on a terrace, balcony or windowsill.

• Flowering time June, July
• Height at maturity 20 cm

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Heucherella Honey Rose

Recent outstanding selection for shade and semi-shade in beds or at the foot of trees.

• Flowering time July to September
• Height at maturity 35 cm

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Tiarella cordifolia Pink Brushes

Will brighten slightly shady areas of the garden! This plant spreads by stolons and can quickly cover large areas.

• Flowering time June to August
• Height at maturity 30 cm

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Tiarella Sugar and Spice

Excellent, very floriferous and vigorous groundcover. Colours difficult spots such as shaded beds.

• Flowering time June, July
• Height at maturity 20 cm

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Heucherella Solar Power

Golden foliage marbled with brown, exceptional. Makes a good groundcover thanks to its creeping habit.

• Flowering time June, July
• Height at maturity 35 cm

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Heucherella Citrus shock

Exclusive variety forming a low, persistent cushion of acid pale green leaves flushed with red. For shady, cool areas of the garden, in understorey.

• Flowering time July, August
• Height at maturity 35 cm

See the product sheet

Planting

Where to plant Tiarella and Heucherella?

Hardy to cold (sometimes down to -20°C), preferring coolness to drought, Tiarellas and Heucherellas are best suited to cool temperate climate. For these plants that appreciate cool conditions, cultivation will be difficult in Mediterranean climate.

They need a rich, humus-bearing soil that stays cool in summer but always well drained, especially in winter. In soils that retain too much moisture their roots risk rotting; it is preferable to plant them on a mound or bank.

They thrive in partial shade, dread bright, burning exposures above all that can scorch their attractive foliage. They nevertheless need a few hours of sun each day to ensure good flowering.

Once well established, Heucherellas can however tolerate dry shade under trees and bushes.

Stoloniferous varieties will quickly occupy the space given to them, being able to rapidly cover a large area.

Clumps increase in size over time but remain always very easy to control.

They are also useful to limit weed proliferation and will advantageously replace short grass meadow in hard-to-access areas of the garden. These perennial groundcovers will save you weeding or will take over from somewhat sad spring bulbs after flowering.

Members of the Saxifragaceae are perfect to bring colour and brightness to cool shade, at the edge of light woodland. Their use depends on cultivar size, small (10 to 15 cm high), medium (20 to 45 cm) or giant (50 to 90 cm high in flower). They come into their own in the role of groundcover in woodland to dress shady areas, banks, as riverside plants, to rapidly colonise bush massifs or crown a wall even in winter.

Tapetum of Heucherella ‘Sunrise Falls’ with superb lemon-yellow foliage in spring then purplish in autumn!

They also make window boxes, pots, urns or hanging baskets in shade from which they will escape gracefully!

When to plant Tiarella and Heucherella?

Planting Tiarellas and Heucherellas is done in autumn from September to November to promote rooting before winter or in spring in cold regions from March to April, outside frost and drought periods.

How to plant Tiarellas and Heucherellas?

Easy to grow, they do well in open ground as well as in containers.

In open ground

These perennial plants with strong spreading habit will do best in soil rich in humus. Add a good shovelful of well-rotted compost or manure at planting. In heavy soil, add coarse river sand to improve drainage.

Space plants about 30 to 40 cm apart and allow 6 to 9 buckets or plug plants per m2 to create a dense tapetum. Plant our plug plants if possible as soon as received.

To colonise a neglected corner of the garden, under trees or bushes for example, or to advantageously replace short grass meadow in little-trodden, shaded areas, you can also plant Tiarellas and Heucherellas en masse. You will be trouble-free for many years!

• Dig a hole 3 to 5 times wider than the rootball
• Loosen soil well
• Place plant in centre of hole without burying the collar too deeply, keeping it slightly below soil surface
• Cover rootball with a mixture of potting soil, garden soil and compost
• Firm down
• Optionally apply organic mulch
• Water copiously then regularly until established

In pots

• In a container, spread a layer of clay balls over a quarter of the height
• Plant Tiarella and Heucherella, collar at substrate level, in a well-drained mix for flowering plants (eg geranium compost)
• Keep rootball always slightly moist

Hanging basket of Heucherella ‘Redstone Falls’

More advice on planting our plug plants on our blog!

Maintenance, pruning and care

Tiarellas and heucherellas (x Heucherella) really need little care to stay attractive all year round. They have only a few essential requirements.

They tolerate any type of well-drained soil, provided they do not lack water in summer.

In pots as in open ground, ensure to maintain sufficient moisture at the base. The soil must always remain fairly cool throughout summer. Mulch the stumps in spring to keep the roots cool during summer. In regions with harsh winters, renew this vegetal mulch (pales of flax…) in autumn to protect them from severe frosts.

In pots, reduce water supply in winter and do not let water stand in saucers. Mulching container-grown specimens can also be helpful.

If rainfall is scarce, water regularly during the first year after planting, then 1 to 2 times per week in periods of high heat or prolonged drought. After that, these plants become more tolerant of short dry spells.

They appreciate soil rich in humus. In poor soil, apply each year at the start of spring a good layer of well-rotted compost by raking in around the plants’ base.

Remove faded flower stalks and wilted leaves as they appear.

At the end of winter, around February–March, tidy the clump by removing leaves damaged by cold when new leaves are just beginning to emerge.

If you wish to limit their spread, pull out surplus stolons from stoloniferous varieties.

Divide the clumps every 3–4 years in October or March to maintain vigour.

Repot every two or three years tiarellas and heucherellas grown in pots.

Diseases and potential pests

If heucherella has no natural enemies, its cousin tiarella can be more vulnerable to slugs and snails, which relish its young shoots in spring. Discover our natural solutions to keep these unwelcome visitors away.

Container-grown subjects can be more sensitive to vine weevils, which devour the roots and ‘punch’ notches out of leaf edges: burn plants that are too heavily infested and spray tansy decoctions as a preventative measure.

Similarly, it is fairly susceptible to powdery mildew during summer. As prevention: see our information sheet How to treat and prevent powdery mildew (white disease).

Abundant flowering of Tiarellas

Propagation

Heucherella and Tiarella multiply easily by clump division or by separating rooted stolons in autumn or in spring.

Division of clumps

Division helps to maintain clumps when the rhizomatous stems age.

• Using a spade fork, pry up part of the stump
• Divide it into several pieces, each with a few roots and a shoot of leaves
• Replant straight away in soil or in a pot

Separation of stolons

• With a spade, separate a rosette of leaves attached to the mother plant
• Dig up the stolon
• Pot up immediately into moist soil so that the base of the seedling is slightly buried
• If carried out in autumn, pot up and store in a frost-free place until spring

Use them and combine them in the garden

Heucherellas and Tiarellas are indispensable in shade gardens, in pink or romantic gardens, in beds or wooded sites with their such colourful foliage and pastel, feathery inflorescences that brighten any cool corner. With their graceful silhouette, they lighten perennials for shade that can be a little heavy or coarser-leaved and serve as backdrop for more spectacular or taller flowers.

Excellent, highly decorative ground-cover perennials in colourful understorey settings, under trees they combine easily with brunneras and pulmonarias and will look splendid in family groups with Heuchera.

An example of an understorey combination: Geranium phaeum ‘Album’, Betula utilis var. jacquemontii, Tiarella cordifolia ‘Moorgrun’, Brunnera macrophylla ‘Jack Frost’ (or other variety with silver foliage), Saxifraga umbrosa and Astrantia ‘Star of Billion’ (or ‘White Giant’)

In the edge of a cool understorey, they are perfect with their shade companions such as ferns, ligularias, Cierges d’argent, Epimedium, hardy geraniums or filipendulas.

Classic partners for Tiarellas and Heucherellas, astilbes, alchemillas and hostas enjoy the same growing conditions and will make a striking display in a softly shaded border.

Under trees, they are welcome among other ground-cover perennials for shade to create a tapetum of colours and subtle textures with woodland anemones, violets, creeping Lysimachia, columbines, Asarum…

They form a classic, fresh tableau with many spring bulbs such as snowdrops, hyacinths, daffodils, primroses and later tulips and colchicums.

An example of a bed combination: Galega orientalis, Lilium regale and Heucherella ‘Brass Lantern’

In a romantic-toned bed, they will grow among white or pink azaleas or cyclamens. At the front of a border, they pair beautifully with columbines, bleeding hearts, pink geums, small violas.

Their foliage, often turning reddish-bronze in autumn, happily harmonises with a wide range of trees and bushes with late colouration such as maples, barberries and deciduous euonymus, smoke trees or grasses with autumnal tones like Pennisetum setaceum ‘Rubrum’ and Miscanthus sinensis ‘Little Miss’.

In pots, new Heucherella hybrids make a striking display in mixed flowering combinations alongside small, airy grasses such as Carex and Stipa or with alyssum, campanulas, daffodils in spring and small cyclamens in winter.