<em>Cimicifuga</em>: to plant, to grow and to care for

Description and botany

The Cimicifugas are hardy perennials in the Ranunculaceae family like anemones. Native to temperate zones of Northern Hemisphere, about thirty different species occur in Europe, Asia and North America. They are shade or partial-shade plants that prefer rich, fresh or moist media. They also favour clayey, neutral to slightly acidic or alkaline soils.

The word Cimicifuga derives from Latin contraction of cimex meaning “bug” and fugare meaning “to flee”. This name would come from unpleasant scent of its flowers thought to repel such insects. It is said that most common species, Cimicifuga racemosa, may act as an insecticidal plant, repelling mosquitoes and other small insects.

Genus Cimicifuga and genus Actaea used to be treated as two distinct genera. The first produces fruit as dry follicles while Actaea forms berries. Today classification has evolved and genera have been merged by most botanists. Thus species may be found under either genus name, for example Actaea racemosa or Cimicifuga racemosa, known as black cohosh. In France this is the species most commonly cultivated in the genus. Second in popularity is Actaea simplex, widely grown for its variety Brunette with brown-purple foliage.

Cimicifugas are known under many common names such as actaea, bugbane, silver candle, stinkbug herb or St Christopher’s herb.

Cimicifuga with beautiful chocolate-coloured foliage

Cimicifuga have deciduous foliage that is cut or even divided, finely dentate, with colours ranging from light green to purple‑violet. For example, variety Cimicifuga simplex atropurpurea is notable for its purple foliage.

Of slow growth, they form dense leafy clumps, more or less rounded, from 60 cm to 1.80 m tall depending on variety, with a spread between 50 and 90 cm.

Flowering of Cimicifugas ranges from late spring to late autumn depending on species and varieties. It appears as majestic upright spikes composed of numerous small usually star‑shaped flowers. Flowering stems, erect or slightly arching, can reach up to 1.30 m in height. These upright white inflorescences gave rise to common name silver candle. However today flower colours range from pure white to pink depending on variety. Actaea matsumurae White Pearl is most remarkable for its pure white flowering.

Depending on variety, flowers emit a distinctive scent, sometimes unpleasant and sometimes deliciously perfumed, even evoking vanilla. Vanilla‑scented varieties include Cimicifuga simplex Brunette, Cimicifuga Carbonella and Actaea simplex James Compton.

Flowering stems of Cimicifugas can be used in bouquets.

After flowering, Cimicifuga flowers develop into fruits whose form varies with species. They may become a small dry fruit that opens at ripeness, a follicle, or small round berries. These small berries in green, white, pink, red or black measure a few millimetres across and some are highly decorative. They remain toxic to humans but seem appreciated by birds. Variety Actaea pachypoda Misty Blue is perhaps most decorative with its white berries borne on red pedicels.

Botanical species

• Black cohosh – Cimicifuga racemosa

Native to North America, this species is most common in gardens. Among actaeaceae most resistant to drought, it stands out by its great height up to 1.80 m and its light green foliage. Its spike flowers are white and appear between July and August. Their scent is not always appreciated. Plant at back of a border, avoiding proximity to terrace or path.

• Silver Candle – Actaea simplex

Native to temperate Asia, it is widely cultivated in gardens. Its autumn flowering extends from August to November, with flowering stems reaching between 1.20 m and 2 m tall. Terminal flower spikes measure between 10 and 30 cm long and are made up of small 2 cm white flowers. This species occurs in many varieties with decorative brown or purple foliage.

Main species and varieties of Cimicifuga

Actaea simplex Carbonella

Foliage colour ranges from chocolate to purplish-violet. It has a more compact habit than variety Brunette. Flowers are pleasantly scented.

• Flowering time October to December
• Height at maturity 90 cm

See the product sheet

Cimicifuga Brunette

A variety with purple foliage and scented, arching white spikes up to 60 cm long.

• Flowering time September to November
• Height at maturity 1,20 m

See the product sheet

Cimicifuga simplex James Compton

A beautiful variety with purplish-violet to almost black foliage and very fragrant flowering.

• Flowering time October, November
• Height at maturity 90 cm

See the product sheet

Cimicifuga japonica Cheju-Do

This small Cimicifuga is notable for its silvery, lobed foliage in spring. Its spikes are very airy and scented.

• Flowering time October, November
• Height at maturity 80 cm

See the product sheet

Actaea pachypoda Misty Blue

This small variety is characterised by early flowering and bluish-tinged foliage in spring. Its scented white flowers give way to decorative white berries borne on red pedicels.

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

See the product sheet

Cimicifuga White Pearl

Actaea White Pearl is stunning with numerous pure white scented spikes that contrast with the light green tone of its foliage.

• Flowering time November, December
• Height at maturity 1,20 m

See the product sheet

Planting

Where to plant cimicifugas?

Cimicifuga can be planted throughout metropolitan France provided its hardiness and requirements for sunlight and soil are respected. Hardy to -15°C, it prefers shade or partial shade. Sunny spots should be avoided to prevent foliage burn.

It thrives in a clay, neutral soil that remains consistently cool and humus-bearing. It tolerates damp ground.

Wind is an enemy of Cimicifuga. It can damage or flatten its flower stems. Therefore, plant it sheltered from wind.

Small-growing cimicifugas can be grown in a pot. Indeed, cimicifuga needs fairly deep soil and a pot may be insufficient for large-growing varieties. For cimicifugas in pots, summer watering and an annual addition of compost are essential.

When to plant cimicifugas?

Ideally, Cimicifuga are planted in spring between March and April but they also tolerate planting between October and November. Avoid planting during frosts or periods of heat.

How to plant cimicifugas?

Cimicifuga should be planted at a density of 3 to 5 plants per square metre. The distance between each plant equals the plant’s span at ripeness. Before planting, remember to soak the rootball in water for 15 minutes.

• Dig a hole three times the size of your rootball.
• Mix 3 to 5 shovelfuls of compost or planting compost with the excavated soil.
• Fill half the hole with this mixture.
• Water the soil thoroughly to settle it.
• Place your cimicifuga plant in the centre of the hole and correctly aligned with ground level.
• Fill the hole completely with soil, taking care to create a basin around the plant.
• Firm the soil and water thoroughly.
• Mulch the plant so the soil does not dry out too quickly.

It is advisable to keep up watering in the first years and to space it out gradually.

After 3 years, your cimicifuga will be well established and will reward you with its finest flowering displays. It is best not to move it to encourage its spectacular flowering.

Read also : How to plant a cimicifuga in a pot?

Cimicifuga or Actaea matsumurae ‘White Pearl’

Care

If the position of your silver candles has been chosen correctly, caring for them will be all the easier for this easy-to-care perennial.

As flowering progresses, deadhead faded flowers to encourage new blooms. At the end of flowering, leave the last flowers and foliage to dry; simply prune the entire dry clump at the return of spring.

In spring, when growth resumes is the right time to apply compost to feed the plant throughout the year.

In summer, it is advisable to maintain a mulch at the base of your silver candles to keep the soil cool and reduce watering. Watering is essential during first years after planting. In subsequent years, only watering during prolonged dry spells is recommended.

If wind flattens the flower stems, stake them.

Easy to grow, cimicifugas are rarely affected by diseases and pests.

Multiplication: division

Silver candles are easily propagated by dividing their rootstock in autumn or spring. Given slow growth of most silver candles, divide only when plants are well established and sufficiently large. Generally, allow 5 to 7 years. This division is carried out simply with a spade, favouring one end of the rootstock. It takes about 3 years to obtain the first dense flowering.

It is also possible to propagate silver candles by sowing, but we do not recommend this method given slow growth and establishment of this plant genus.

Uses and associations in the garden

Compose an autumn scene in partial shade by pairing your silver candles with European cyclamens, hostas, Japanese anemones or pink or blue autumn asters. The white to pink-tinged flowers of silver candles combine with green-to-purple foliage and flowers in white, pink, mauve or bluish tones.

An example of a planting in partial shade: Ligularia dentata ‘Britt-Marie Crowford’, Cimicifuga simplex ‘Atropurpurea’, Hosta ‘Tattoo’ and Holcus mollis ‘Albovariegatus’

Alternatively, choose a shady border flowering all year round. For spring flowering, favour barrenwort, wood hyacinths, dead-nettles, forget-me-nots, Solomon’s seal and periwinkles. For summer flowering, rely on heucheras, hardy geraniums or lady’s mantle. For the rest of the year, foliage of ferns, helxines and carex are ideal to dress a cool shady corner.

Think about playing with height in your border by placing lower-growing plants in front of the silver candles. Place a dark backdrop behind your silver candles to set off their pale flower spikes. For this, plant shade trees or bushes with dark foliage such as a conifer, holly, viburnum or euonymus.

Play with foliage contrasts; silver candle varieties with purple foliage will pair beautifully with anise-green or pale green foliage of heucheras or carex.

Another planting idea that works well: Cimicifuga ‘James Campton’, Stipa gigantea in the background, Persicaria amplexicaulis ‘Blackfield’ or ‘Fat Domino’ for example and Helenium ‘Ranchera’ or ‘Moerheim Beauty’

Did you know?

Cimicifugas are known for certain medicinal properties, notably Cimicifuga racemosa, the most common species. Roots and leaves of this species are reputed to alleviate women’s conditions: painful periods, hot flushes and depression associated with menopause.