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

Description and botany

Cimicifugas are hardy perennials of the Ranunculaceae family, like anemones. Native to temperate regions of the Northern Hemisphere, there are about thirty different species in Europe, Asia and North America. These are shade or partial-shade plants that prefer rich, cool or moist mediums. They also favour neutral to slightly acidic or alkaline clay soils.

The name Cimicifuga comes from the Latin contraction of cimex meaning “bug” and fugare meaning “to put to flight”. This name would stem from the unpleasant smell of some flowers, reputed to drive away such insects. It seems that the most common species, Cimicifuga racemosa, may even act as an insecticidal plant, repelling mosquitoes and other small insects.

The genus Cimicifuga and genus Actaea were formerly treated as two distinct genera. The first genus fruits as dry follicles while genus Actaea forms berries. Today most botanists have merged the genera, so species may be found under either genus name, for example Actaea racemosa or Cimicifuga racemosa, known as black cohosh. In France this species is the most widely cultivated of the group. In second place comes Actaea simplex, popular for its variety Brunette with brown‑purple foliage.

Cimicifugas are marketed under many names such as actaea, bugbane, silver candle, stinkweed or St Christopher’s herb.

Cimicifuga with beautiful chocolate foliage

Cimicifuga foliage is deciduous, often finely divided and dentate, with colours ranging from light green to purple‑violet. For example, variety Cimicifuga simplex atropurpurea is notable for its purple foliage.

Slow in growth, they form dense, leafy clumps more or less rounded from 60 cm to 1.80 m high depending on variety, and 50 to 90 cm wide.

Flowering varies from late spring to late autumn depending on species and variety. It appears as majestic inflorescences in upright spikes made up of numerous small, typically star‑shaped flowers. Their flowering stems, upright or slightly arching, can reach up to 1.30 m tall. These upright white inflorescences gave rise to the common name silver candle. Today inflorescence colours range from pure white to pink depending on variety. Actaea matsumurae White Pearl is particularly noteworthy for its pure white flowering.

Depending on variety, flowers emit a particular scent, sometimes unpleasant and sometimes delightfully scented, even evoking vanilla. Varieties with a sweet, vanilla‑like perfume include Cimicifuga simplex Brunette, Cimicifuga Carbonella and Actaea simplex James Compton.

Flowering stems of Cimicifugas can be used in bouquets.

After flowering, Cimicifuga flowers turn into fruits that vary with species. They may form a small dry fruit that opens at ripeness (a follicle), or they may form small round berries. These small berries, green, white, pink, red or black, measure several millimetres across and some are very decorative. They remain toxic to humans but appear to be enjoyed by birds. Variety Actaea pachypoda Misty Blue is perhaps the most decorative with its white berries borne on red pedicels.

Botanical species

• Black cohosh – Cimicifuga racemosa

Native to North America, this species is the most common in gardens. Among Actaeas it is one of the more drought‑tolerant, distinguished by its great height up to 1.80 m and light‑green foliage. Its spike flowers are white and appear between July and August. Their scent is not always appreciated. Plant away from terraces or paths, ideally toward back of a border.

• Silver candle – Actaea simplex

Native to temperate Asia, this species is widely cultivated in gardens. Its autumn flowering extends from August to November and is produced on flowering stems reaching between 1.20 m and 2 m tall. Terminal flower spikes measure between 10 and 30 cm long and consist of small white flowers about 2 cm across. 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

Variety with purple foliage and scented, arching white spikes measuring up to 60 cm.

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

See the product sheet

Cimicifuga simplex James Compton

Beautiful variety with purplish-violet, almost black foliage and very fragrant flowering.

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

See the product sheet

Cimicifuga japonica Cheju-Do

Distinctive feature of this small Cimicifuga is its silver-glazed, lobed foliage in spring. 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 blue-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 sublime with its 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 mainland France provided its hardiness and requirements for light and soil are respected. Hardy down to -15°C, it thrives in shade or partial shade. Avoid sunny spots to prevent leaf scorch.

It prefers clayey, neutral, humus-bearing soil that stays consistently cool and moist. It tolerates wet ground.

Wind is an enemy of Cimicifuga. It can damage or topple its flower spikes. Therefore, plant it in a sheltered spot.

It is possible to grow cimicifugas in pots when they are small-growing. Indeed, Cimicifuga needs fairly deep soil and a pot may be insufficient for large-growing varieties. For potted cimicifugas, 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 any heatwaves.

How to plant cimicifugas?

Cimicifugas are planted at a density of 3 to 5 plants per square metre. Distance between each plant should equal the plant’s spread at maturity. Before planting, soak the rootball in water for 15 minutes.

• Dig a hole three times the size of the rootball.
• Mix 3 to 5 spadefuls of compost or planting soil with the excavated soil.
• Fill half the hole with this mixture.
• Water copiously to settle it.
• Place your cimicifuga plant in the centre of the hole, aligned with soil level.
• Fill the hole completely with soil, making a basin around the plant.
• Firm the soil and water thoroughly.
• Mulch around the plant to prevent the soil drying out too quickly.

Keep up watering during the first years and gradually reduce frequency.

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

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

Cimicifuga or Actaea matsumurae ‘White Pearl’

Care

If position for your bugbanes has been chosen correctly, caring for this easy-care perennial will be all the easier.

As flowering progresses, cut off faded flowers to encourage formation of new flowers. At end of flowering, leave last flowers and foliage to dry; simply prune the dry clump back entirely when growth resumes in spring.

In spring, when growth resumes is the right time to add a dressing of compost to feed the plant throughout the year.

In summer, it is advisable to keep mulch around the base of your bugbanes to keep soil cool and reduce watering. Watering is essential during first years after planting. In following years, only watering during prolonged dry spells is recommended.

If wind flattens the flowering stems, stake them.

Easy to grow, cimicifugas are largely unaffected by diseases and pests.

Multiplication: division

Silver candles are easily propagated by dividing their rootstock in autumn or spring. Given the slow growth of most silver candles, division should only be carried out when plant is well established and large enough. Generally, wait 5 to 7 years. This division is simply carried out with a spade, favouring one end of the rootstock. Allow about 3 years for first dense flowering.

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

Uses and companion planting in the garden

Create a partial-shade autumn scene by pairing your silver candles with European cyclamens, hostas, Japanese anemones or pink or blue autumn asters. The white flowers with a pink flush of silver candles combine with green to purple foliage and white, pink, violet or bluish flowers.

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

Alternatively, opt for a shade border flowering all year round. For spring flowering favour barrenworts, wood hyacinths, lamiums, forget-me-nots, solomon’s seal and periwinkles. For summer flowering rely on heucheras, hardy geraniums or alchemillas. And for the rest of the year the foliage of ferns, helxines and carex will be ideal to dress a cool shady corner.

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

Play with foliage contrasts; varieties of silver candles with purple foliage will pair wonderfully with lime or light-green foliage of heucheras or carex.

Another combination 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?

Cimicifuga are known for certain medicinal properties, notably those of the most common species, Cimicifuga racemosa. Roots and leaves of the latter are reputed to combat women’s health problems: painful periods, hot flushes and depression associated with menopause.