<em>Rodgersia</em>: planting, cultivation, care

Description and botany

Le Rodgersia is a perennial of the family Saxifragaceae, native to humid, mountainous zones, fresh forests and copse of Burma, Korea, China and Japan. This plant has acclimatised to temperate gardens and parks.

The genus comprises 6 species and numerous cultivars. Among those most common in our climates are Rodgersia aesculifolia, often called “chestnut-leaved Rodgersia”, Rodgersia pinnata or “pinnate-leaved Rodgersia”, Rodgersia podophylla or “duck’s-foot-leaved Rodgersia”, Rodgersia sambucifolia or “elder-leaved Rodgersia”, and Rodgersia aesculifolia var. henrici, a natural variety of the chestnut-leaved Rodgersia.

Rodgersia takes 3 to 5 years to establish and reach full development. The plant develops slowly on fleshy, scaly, running rootstock. It will vegetate during the first years, flowering only after two years of cultivation. Its slowness to establish is matched by its remarkable longevity! Without being invasive, it gradually spreads to form stumps of more than 1 m² and colonise the ground over time.

It is a plant with an architectural, bushy habit. Rodgersia forms a quite dense, imposing clump that can reach 1.5 m in height in flower, with a 2 m spread.

Rodgersia is notable for its powerful, majestic growth. This deciduous foliage, particularly elegant and graphic, disappears completely in autumn at first frosts.

In spring, the fleshy stump produces a large clump of big petiolate, pinnate or more or less palmate leaves with more or less dentate margins. Leaves can reach 80 cm in length, divided into 3 to 11 large lanceolate, oblong or ovate leaflets.

Some foliage: Rodgersia pinnata, Rodgersia ‘Bronze Peacock’, Rodgersia podophylla (photo Megan Hansen‑Flickr), Rodgersia pinnata ‘Dark Pokers’

Some leaves are woolly or rough, others glossy; most are crumpled or puckered, strongly veined. Foliage of Rodgersia pinnata very much resembles that of horse‑chestnuts, while foliage of Rodgersia podophylla is as palmate as a “duck’s foot”!

Green veins marked with brown‑red on Rodgersia aesculifolia, bronze then dark green turning purple, red or orange in autumn on Rodgersia podophylla, the shades of this ample palmate foliage vary by species and variety, sometimes changing through the seasons.

Evolution of foliage of a Rodgersia podophylla: young leaves dark purple in spring, green in summer and red‑orange in autumn

What distinguishes form henrici of the type species Rodgersia aesculifolia is its young spring foliage bronze‑purple at bud burst period, becoming dark green in summer.

Some cultivars of Rodgersia pinnata such as ‘Bronze Peacock’ and ‘Chocolate Wings’ develop changing foliage evolving from bronze‑brown or chocolate brown to deep red before fading.

Summer flowering in large, cloud‑like panicles on tall, robust stems of Rodgersia often takes spectacular forms.

From early to late summer, the plant sends up large, impressive spikes of flowers, sometimes carried up to 1.5 m above the palmate foliage clumps. These large, feathery, branched inflorescences 20 to 70 cm long bear clusters of starry flowers pure white, ivory or pale pink to purplish pink, held on sometimes reddish stems. They are followed by capsules of dark red or brown fruit of little decorative interest.

Some Rodgersia flowers: Rodgersia pinnata ‘Superba’ (photo Rob Bakker‑Flickr), Rodgersia pinnata ‘Chocolate Wings’, Rodgersia aesculifolia ‘Irish Bronze’, ‘‘Rodgersia ‘Bronze Peacock’

The very graphic, airy plumes make beautiful fresh summer bouquets.

Despite its exotic appearance, Rodgersia shows good hardiness, at least down to -25°C. It is a shade‑loving plant that prefers cool conditions, ideal near water features or at edge of damp understorey, where it brings a lush, exotic note.

It favours fresh, moist soils that retain water well, with a preference for non‑calcareous ground; a typically acid or neutral understorey soil will suit it perfectly! It is an indispensable perennial in heavy soil. It will tolerate non‑scorching sun only if soil remains deeply moist in summer.

Main species and varieties

Most popular

Our favourites

Rodgersia aesculifolia

Its horse‑chestnut leaves form an attractive bushy clump with starry cream‑white flowers that turn pink towards the end of flowering.

• Flowering time September, October
• Height at maturity 1 m

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Rodgersia podophylla

Forms a majestic clump of large palmate leaves bronze‑coloured at emergence, then dark green with bronze highlights, turning purple, red or orange in autumn.

• Flowering time July, August
• Height at maturity 1 m

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Rodgersia pinnata

Foliage of this variety is very reminiscent of horse‑chestnut. Ideal near water features, alongside ferns and grasses.

• Flowering time July to September
• Height at maturity 1 m

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Rodgersia aesculifolia var. henrici

One of the most spectacular, with flowering in large cloud‑like purplish‑pink panicles dominating very handsome deep‑green horse‑chestnut foliage. A real star of cool, moist sites!

• Flowering time August, September
• Height at maturity 1,20 m

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Rodgersia pinnata Bronze Peacock

Horse‑chestnut palmate foliage of antique bronze‑brown, almost metallic, changing through the seasons. Irreplaceable in moist, shaded spots, even when space is limited.

• Flowering time July, August
• Height at maturity 50 cm

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Rodgersia pinnata Chocolate Wings

A striking Rodgersia, with an architectural habit and ample horse‑chestnut palmate chocolate‑brown foliage changing through the seasons.

• Flowering time August, September
• Height at maturity 1 m

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Rodgersia aesculifolia Irish Bronze

Admired for its large decorative bronze‑coloured leaves and pink flower buds that open to ivory white.

• Flowering time June, July
• Height at maturity 1 m

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Planting

Where to plant Rodgersia

Hardy, Rodgersia tolerates frosts down to −25 °C, thriving in cool, humid regions and particularly on the north-west coast of the country. Its cultivation can be more difficult in Mediterranean climate that is too dry and hot in summer.

Its only requirement is moist soil; this plant does not tolerate lack of water: it will wither in dry soil. Rodgersia dislikes drought.

It prefers shade and cool conditions but will tolerate sun in temperate regions, provided the soil remains constantly moist and cool. However, site it sheltered from dry, cold winds and direct sun, which can damage its foliage.

Easy to grow, it will be most luxuriant and vigorous in soil rich in organic matter.

It typically prefers woodland soil, neutral or acidic, free of lime.

While it likes rather heavy soils that never completely dry out in summer, it is, however, vulnerable to excess water during winter; provide perfectly drained soil.

Choose a well-exposed site that will allow it to reach its full size. This perennial is very impressive, slowly but surely forming fairly opulent clumps up to 2 m across without ever becoming invasive despite its running rootstocks. The foliage truly becomes large when the plant is grown in a partially shaded spot with high ambient humidity in summer.

Rodgersia is at its best as a woodland young plant, waterside young plant, on pond margins, where it lights up the area with its bright flowering and its imposing palmate foliage.
It will make a statement in beds of fresh heather soil, as a specimen or planted in numbers along the edge of a shaded path.

When to plant Rodgersias

Rodgersias are planted in autumn (September–October) in temperate zones, or in spring from March to May in cold climates.

How to plant Rodgersia

In open ground

Space plantings well: at ripeness, Rodgersia reaches a spread of 1 to 2 metres. Do not be misled by its small size in the bucket!

Space young plants at least 0.70 to 0.80 m apart in worked, loosened soil enriched with well-rotted compost or manure.

• Dig a hole 2 to 3 times wider than the rootball
• Fork over the soil to a depth of 30–40 cm
• Spread a layer of gravel at the bottom of the planting hole
• Add a good shovelful of well-rotted compost or manure to the bottom of the hole before placing the rootball
• Bring the soil back to enclose the roots and firm down
• Water copiously until established and throughout the first year after planting
• Carefully mulch the base in late May with an organic mulch to preserve moisture during summer

Planting Rodgersia in a pot

Despite the vigorous growth of this perennial, container cultivation is possible because Rodgersia’s roots are fairly shallow. However, the rootstocks can quickly tend to escape their container: provide a large pot of at least 70 cm diameter.

• Plant the rootball in a mix of garden soil, preferably clayey and enriched
• Spread a good layer of grit or clay pebbles at the bottom of the pot beforehand to improve drainage
• Mulch
• Water very regularly; never let the substrate dry out

Care and maintenance

This plant is not delicate and can be left alone provided conditions suit it.

Rodgersia is a perennial that likes water. It creates large, exotic-style displays until the frosts, but it must be watered often and generously!

Freshness and moisture at its base are the secrets to to grow this colossal perennial! Soil must be kept sufficiently moist, otherwise it will quickly decline in prolonged drought. A cool soil will allow vigorous development.

Water very regularly during first year to ensure good establishment. Afterwards, only once a week, especially during hot spells.

Mulch at end of May to reduce watering and evaporation. In very cold climate, mulch the stump with dead leaves in autumn; late frosts may damage young, still-tender shoots.

Every two years, in March, spread a few shovelfuls of compost over the stump.

Remove faded stems after flowering to encourage foliage development or leave them to dry on the plant to harvest the seeds.

Wait until spring to tidy the clump and remove withered leaves.

Divide the stumps into pieces in March to perpetuate the plant.

Potential diseases and pests

Hardy and robust, Rodgersia has few enemies.

It is nevertheless sensitive to dry, cold winds and scorching sun and to slugs in spring that can damage young shoots, though much less than hosta, its shade companion. Use mechanical traps or slug treatment every year from February. Take inspiration from our natural methods!

Potted Rodgersias can be more vulnerable, notably to vine weevil larvae that devour roots… Watch for attacks by these small beetles that notch leaf margins: burn them, remove young plants that are too badly infested. Spray tansy decoctions.

Propagation

Sowing of Rodgersia is possible, but requires a lot of patience. We recommend instead division of stumps in spring, in March. Do not intervene until after 4 or 5 years when plant is well established.

1. With a fork-spade, dig up part of the stump before foliage develops
2. With a spade, slice off a good-sized clump
3. Replant divisions immediately in well-worked soil enriched with compost

Associate

Essential in shade gardens and by water’s edge in marsh gardens, Rodgersia with its imposing foliage of large palmate leaves and its pastel feathery inflorescences brightens cool areas.
At edge of a cool, damp understorey, it is perfect with shade companions such as ferns, ligularias, Peltoboykinia, goat’s beard, Epimedium, filipendulas, heucheras or alongside Asian primulas or begonia grandis evansiana.

An example of a combination: Hostas, Rodgersia podophylla, Catalpa bignonioides ‘Aurea’, flowering dogwoods (Le Sous-Bois, Belgium)

Classic companions for Rodgersia, astilbes and hostas enjoy the same growing conditions and will make a statement in a cool shaded border.

Among other excellent companions are grasses (Carex, gardener’s rush, Japanese rush, tufted hair-grass).

At edge of a pond, pair with other moist-bank perennials such as gunnera or darmera, marsh euphorbias, Siberian iris, perennial lobelias.

An idea for a pondside combination: Gunnera tinctoria, Rodgersia pinnata ‘Hercule’ (R. pinnata or other species also work well), Iris sibirica (‘Blue King’, ‘Caesar’s Brother’), ferns…

Rodgersia complements a bush bed for heather soil such as rhododendrons.
To enhance edge of a shaded path, set it off with a groundcover carpet of polygonums, golden sagina, candelabra primulas and liverworts.

Its attractive palmate leaves, often turning bronzy-red in autumn, harmonise beautifully with a wide range of trees and bushes with late colouring such as maples, barberries and deciduous euonymus, smoke trees, sumachs and grasses with autumnal tints.