<em>Stewartia pseudocamellia</em>, false camellia: planting, pruning, care

Description and botany

Stewartia, or Stuartia, is a small tree or large bush of family Theaceae, like tea and its better-known cousin camellia to which it is closely related. Genus includes about 80 species of trees and bushes native to wooded mountains or stream banks of Japan, South Korea, China and North America. American species such as Stewartia ovata are considered vulnerable or endangered and are rare in our latitudes.

Four main species are grown for ornamental purposes in gardens:

• Stewartia pseudocamellia, sometimes nicknamed Stewartia false-camellia, and its varieties such as Stewartia pseudocamellia ‘Koreana’ with large flowers
• Stewartia rostrata, very hardy (down to -20°C)
• Stewartia monadelpha, favoured by bonsai enthusiasts for its regularly tiered habit
• Stewartia sinensis, prized for very handsome decorative bark

All flower in summer and are valued for autumn colours as well as for colourful bark in winter.

Slow to establish and slow-growing, it eventually forms after many years a true small tree that will rarely exceed 5–6 m in our gardens, with a spread of 3–5 m at ripeness, whereas in native regions it can reach up to 15 m. It displays a fine, well-balanced branching from the base. A slowness matched only by longevity — venerable specimens of two to three hundred years are known.

Stewartia sinensis – botanical illustration

Habit differs markedly according to species: conical, ramified very low, even columnar in Stewartia pseudocamellia, spreading pyramid crown then trailing with age in S. rostrata, erect and regular in Stewartia monadelpha. Crown generally rounds with time.

Stewartia is notable for extremely decorative bark that exfoliates over the years. Smooth cinnamon-red bark peels in fine plates from pink to grey-beige, orange to purplish-brown according to variety, very attractive in winter. Only Stewartia rostrata has unremarkable bark.

In Stewartia, deciduous and elegant foliage remains attractive outside flowering period as it takes on splendid autumn colours. These glossy, entire, obovate to elliptical, rather leathery leaves are 3–10 cm long, with strongly marked veins and finely dentate margins. Silky and paler beneath, they are bright to dark green until late summer, more rarely variegated cream in some cultivars, then turn shades from orange to scarlet and purplish before falling late in autumn.

From May–June to August, Stewartia is covered in pretty flower buds opening into simple, delicate flowers. They appear solitary in axils of leaves and bloom all along shoots. They open as widely displayed silky cups, 3–6 cm across, made of five rounded pure white petals, sometimes streaked with pale pink, edged by elongated or slightly twisted sepals in Stewartia rostrata. They show a yellow or purplish centre with anthers yellow-orange or violet depending on variety. Their infinite delicacy recalls shape of wild rose or camellia flowers, hence nickname false camellia; “Pseudocamellia” also means in Latin “resembling camellia”. Petal edges are sometimes attractively fringed. Short life of individual flowers is compensated by abundance as they succeed one another for nearly two months. Although scentless, they lend great elegance.

Plant in light shade, sheltered from cold winds, preferably in acidic soil such as heather soil, not too calcareous, and that remains cool even in summer.

With slow growth, Stewartia suits all garden sizes and can be used in a flowering hedge, planted as a specimen, at woodland edge or in a shaded mixed border.

Latin name honours John Stuart, botanist and British prime minister of 18th century.

Main species and varieties

Most popular

Stewartia pseudocamellia

This species is the most widely cultivated. Everything about it is lovely: the flower, the fruit, the autumn foliage, even the bark! Relatively compact, it suits gardens of all sizes.

• Flowering time August, September
• Height at maturity 4,50 m

See the product sheet

Stewartia pseudocamellia Koreana

This cultivar differs from the type species by its broader leaves and more open flowers. It is one of the hardiest (down to -25°C). Plant as a specimen, or combine with other plants in lime-free soil.

• Flowering time July to September
• Height at maturity 6 m

See the product sheet

Our favourites

Stewartia rostrata

One of the hardiest and least demanding regarding soil, its summer flowering is more abundant and more colourful than that of other Stewartia. However its bark is rather ordinary. Ideal for a small garden.

• Flowering time July
• Height at maturity 6 m

See the product sheet

Stewartia monadelpha

A species well known to bonsai enthusiasts who appreciate it for its regularly tiered silhouette, its extremely decorative bark and its splendid autumn colours.

• Flowering time July to September
• Height at maturity 6 m

See the product sheet

Planting

When to plant Stewartia?

Very hardy in ground (from -15°C to -25°C depending on species), Stewartia is fairly easy to acclimatise except perhaps in Mediterranean climate, which is too hot and dry in summer. However, in regions with long winters it is advisable to give it a very sheltered spot as late frosts can compromise buds and young shoots, especially on young specimens, which are more fragile.

Native to woodland understorey, it likes cool conditions and is best grown in partial shade, at a push in sun if the soil remains cool. It dislikes deep shade. As for soil, it is less demanding than its cousin the camellia; it will make do with ordinary, neutral or slightly acidic soil, preferably cool, light and humus-bearing, not too dry, without excess lime.

Of slow growth and compact habit, it suits small gardens well. Still give it enough room so it can spread freely — allow roughly 2 to 5 metres across. It tolerates transplantation poorly; so think carefully about position before planting.

It will be magnificent whether isolated in the middle of a short grass meadow, or in a small flowering hedge, or in a bed of bushes, alongside other plants for non-calcareous soil (Magnolias, Rhododendron, azaleas, Hydrangea, Hamamelis, Pieris, Camellias, Kalmias, Japanese maples), or in a large pot on the terrace.

When to plant Stewartia?

Planting in spring, from March to April after the worst frosts, will favour establishment.

How to plant Stewartia?

In open ground

If your soil is too calcareous, improve it with a supply of heather soil. Allow a space of 5 to 6 m wide. Once well established, avoid moving it — its roots tolerate transplantation poorly.

• Dig a hole 3 times wider than the rootball and 40 to 50 cm deep; the Stewartia must not be planted too deeply
• Plant the bush in a mixture of compost and heather soil: the top of the rootball should be covered by 3 cm
• Ensure the tree is perfectly upright
• Spread an organic mulch of pine bark or dead leaves
• Water regularly for the first 15 days after planting to keep the soil cool

In a pot

The modest growth of Stewartia makes this use perfectly possible. It tolerates pot culture very well in regions south of the Loire; elsewhere potted specimens will be more sensitive to severe frosts. It will thrive in a large container (30 to 40 cm diameter) filled with a fresh, very free-draining mix, based on 1/3 heather soil, 1/3 potting compost and 1/3 garden soil not too calcareous, kept consistently moist because in a pot it will not tolerate even temporary drought.

Place a layer of gravel or clay pebbles at the bottom of the container before planting.

Stewartia pseudocamellia: flower and autumn foliage

Maintenance, pruning and care

In summer, monitor water needs during first year after planting of young Stewartia: water once a week and thoroughly in dry weather, soil must never be dry, it dislikes drought and likes its roots kept cool during summer heat. Once well established, water only in case of hot weather.

Apply an organic mulch (pine needles that will acidify soil) to keep roots cool in summer.

In winter, water occasionally if it does not rain.

In autumn, you can fertilise with a little compost by lightly forking around the base.

In regions north of the Loire, protect bush from severe frosts by covering stump with a 5–7 cm layer of mulch made from leaf mould and shredded bark. If late frosts are a concern, cover with a winter fleece. Young specimens must be protected from severe frosts for at least 3 years.

Pruning is not necessary for Asian species, they do very well without intervention. However, it can be useful to clear lower trunk to highlight bark in winter.

About every 3 years, after flowering, from February to April:

1. Remove crossing branches and dead wood
2. Trim branch tips slightly to rebalance branches

When grown in good conditions, Stewartia is not very susceptible to diseases and pests. However, too calcareous soil can cause chlorosis, responsible for yellowing of leaves and, over time, decline of the tree.

Propagation

Stewartia is rather difficult to propagate; sowing is possible but tedious and very slow (2–5 years to germinate), layering is always feasible on branches closest to ground, but results are slow as well and separating a viable layer generally takes 2 years. We recommend stem cuttings in spring.

How to take cuttings?

Allow 1 year for complete rooting.

• In May–June, take shoots 10 cm long
• Remove all leaves from lower part
• With a small knife, strip bark over 2–3 cm
• Insert cuttings into a well-draining mix of turf and perlite
• Place in shade, enclosed under plastic
• Mist cuttings regularly with a sprayer
• During summer, re-pot cuttings into buckets
• Overwinter them frost-free until following spring
• Plant out in open ground next spring

Companion planting Stewartia in the garden

Still too little known, Stewartia is nonetheless a very handsome bush that fits easily into any garden provided it can be offered a shaded spot. Magnificent throughout summer with its profusion of large white camellia-like flowers, it is also essential to enliven garden in autumn with foliage taking sumptuous colours and in winter with its colourful bark. As it dislikes lime, it pairs easily with ericaceous plants. It is the perfect guest for white gardens or romantic gardens, bringing much softness and freshness.

An example of a combination: Stewartia with, beneath its canopy, blue Hostas (‘Fragrant Blue’, ‘Halcyon’), or variegated with blue (‘June’, ‘Frances Williams’, ‘El Niño’), Milium effusum ‘Aureum’, Brunnera macrophylla ‘Jack Frost’ or another variety, Campanula poscharskyana ‘Stella’ or the species

Its large white flowers provide lovely brightness and its glossy green foliage adds density to a large, somewhat dull partial-shade border. Place at back of border mixed with shade-loving acidophilous plants like small rhododendrons, ferns with finely divided fronds and Hostas, which will offer an ideal contrast of form.

Against a permanent green background made up of conifers and bushes with evergreen foliage, it will be magnificent alongside Calycanthus, Hamamelis and Fothergilla, equally charming bushes.

In summer, Stewartia also makes a handsome grouped specimen on woodland edge. It combines well with bushes such as Andromeda, Azaleas, Kalmia, Camellias and Hydrangeas, which will complement its flowering.

In a flowering hedge, it will sit alongside a handsome Cornus kousa, viburnums, Mexican orange blossom, spireas or Deutzia.

To set alight shady corners of garden in autumn, think of Acer, Chinese azaleas, Leucothoe, Nandina and tulip tree, with their splendid autumn hues to accompany it.

For a colourful winter garden and to showcase its decorative bark, why not plant it near the highly original Edgeworthia chrysantha, and dogwoods with colourful wood such as Cornus alba ‘Bâton Rouge®’.

You can also dress base of this Asian tree with some Japanese primroses, a Magellan Fuchsia or autumn bulbs such as white Naples cyclamens.