Tree · Theaceae
Japanese Stewartia
Stewartia pseudocamellia
Every season sharpens its look: white summer cups, fiery fall leaves, and gray, orange, and rust bark.
Partial shade
Every 3–7 days
USDA 5–8
12–40 ft · 3.7–12.2 m
Overview
Japanese stewartia is a small deciduous tree in the tea family, the same group as the camellias, and up close it changes character with the seasons. Through early and mid summer it opens white, cup-shaped flowers with rounded petals cradling a boss of stamens. In fall the leaves flare to deep red and orange, and year-round the trunk shows flaking bark that peels in patches of gray, orange, and rust.
It is a tree that rewards a slow, patient look rather than a quick one. It grows slowly and settles into a new spot slowly, and it will not stand drought, baking heat, or waterlogged roots. With the site right, though, it asks for little, and that lets the fine detail of its bark and bloom take center stage as a specimen.
Plant it close to where you walk, where the eye can pick out the mottled trunk and the summer cups at close range. Give it moist, acidic, well-drained soil and a spot with morning sun and cover from harsh afternoon glare, and it delivers years of finely detailed, four-season interest.
Care
The short version: part shade with cover from hot afternoon sun, moist and acidic well-drained soil that never dries out or stays soggy, and patience while it slowly settles in.
Light
Stewartia does best in part shade with cover from hot afternoon sun. It will take full sun in cooler climates, but where summers run hot the thin leaves scorch at the edges, so morning light with afternoon shade keeps the foliage clean and whole.
Water
Keep the soil evenly moist, soaking it deeply every 3 to 7 days in dry weather. The tree has no drought tolerance, so the root zone must not dry out, and a mulch layer over the soil holds moisture and keeps the fine roots cool.
Soil
Plant it in moist, well-drained, acidic soil rich in dark organic matter, ideally a loose sandy loam, at a pH of 5.0 to 6.5. It does poorly in heavy, sticky clay or in dry, rocky, or waterlogged ground, so loosen and enrich the site before planting.
Temperature
The tree is hardy from about -20°F to 86°F (-29°C to 30°C), taking sharp winter cold in stride but wilting under extreme summer heat. In hot regions, afternoon shade and steady moisture keep the leaves from crisping.
Humidity
Average outdoor humidity suits it, so there is no reading to chase. What counts far more is steady soil moisture and cover from drying heat, since hot, parched air is what browns and curls the leaf edges.
Feeding
Feed it once in early spring with a balanced or acid-forming slow-release fertilizer made for acid-loving woody plants. One seasonal feeding is enough, and an acid-lover formula holds the soil on the acidic side its roots prefer.
Pruning
The tree needs almost no pruning. Take out only dead, damaged, or crossing branches in late winter or early spring while it is bare and dormant, and otherwise let the slender, layered branches build their own graceful shape.
Repotting
Stewartia is rarely repotted and resents having its roots disturbed, so leave an established plant be. Roots coiling around the drainage holes, water sluicing straight through, or new shoots that stall are the signs a young potted tree has run out of room.
Size & spacing
Give it room, since over many years it can rise 12 to 40 feet (3.7 to 12 m) tall and spread 8 to 25 feet (2.4 to 7.5 m) across. Set it well clear of walls and other trees so the open, layered canopy and the mottled trunk stand out in full view.
When to plant
Stewartia sulks when it is moved, so gentle handling and good timing count. Set out young container-grown trees in spring to give the roots a full season to grip the soil, and watch for the white cup-shaped flowers opening from June into August.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring, using young container-grown plants for best establishment
- Harvest: White cup-shaped flowers in early-to-mid summer (June to August)
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
This tree carries few serious pests, and most of its trouble shows on the roots or across the leaves rather than as insect damage. Read the foliage closely, since wet feet and dry summer heat leave their marks first in browned edges and limp, fading leaves. Match the look below and correct the conditions before the tree slides into decline.
Limp, yellowing leaves and branches dying back
Leaves that hang limp and fade to yellow, with bare twigs creeping down from the crown, usually mean root rot underground. In soil that stays soaked, the fine roots darken and go soft and slimy, and once they rot they can no longer push water up to the canopy. Move young trees to a raised, freer-draining spot, hold back the hose while the ground is still wet, and mix crumbly organic matter into the dense soil to loosen it.
Fix:
- Improve drainage or relocate young trees to a better-drained, raised site
- Reduce supplemental watering once soil is saturated
- Amend planting area with organic matter to improve structure
Crisp brown rims along the leaves in summer
When the leaf edges and pointed tips go brown, dry, and papery, that is leaf scorch from drought and hot, exposed sun. The browning bites in along the rim first and shows worst on the face of the tree that catches the fiercest afternoon light, right after the root zone dries out. Soak the ground deeply through dry weeks, blanket the roots in mulch to cool them and trap moisture, and cast some afternoon shade over the tree where the light burns hardest.
Fix:
- Water deeply during dry periods
- Apply mulch over the root zone to retain moisture and keep roots cool
- Provide afternoon shade where exposure is harsh
Toxicity
For a home with pets, the answer is easy: Japanese stewartia is not toxic. It does not appear on the ASPCA's poison lists, and nothing in its leaves, bark, or seed capsules is known to harm cats, dogs, horses, or other animals. As with any plant, a big mouthful of leaves might upset a stomach, but there is nothing dangerous in any part of it.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
A cat that rubs its cheek along the smooth bark or paws a dropped leaf takes no harm, since the tree holds no known toxins.
Dogs Safe
A dog mouthing a low, slender branch is in no danger, though swallowing a big wad of leaves may bring a brief, harmless bout of stomach upset.
Horses Safe
Horses that crop the grass beneath the spreading canopy come to no harm, as the tree holds no compounds known to trouble them.
Rabbits Safe
Rabbits nosing at the low bark or a fallen leaf run no poisoning risk, since neither the foliage nor the bark carries anything toxic.
Livestock Safe
Cattle, goats, and sheep grazing around the trunk stay safe, because no part of this tree is toxic to grazing animals.
Birds Safe
Birds that perch on the flaking branches or peck at the dry seed capsules take no harm from this non-toxic tree.
People Safe
The tree poses no poisoning risk to adults or children who handle its leaves or peeling bark. It is grown for its white flowers and mottled trunk, not for eating, so no part is meant for the table.
No special handling required; as with any plant, discourage pets from chewing foliage to avoid mild stomach upset.
Varieties
A few named selections and close relatives stand out, chosen mostly for bigger blooms or more striking bark. These are the ones you are most likely to find.
'Ballet'
'Ballet' opens larger white flowers and holds them on a broad, spreading frame of branches.
'Milk and Honey'
'Milk and Honey' is prized for its showy flaking bark and its dependable flush of flowers.
Stewartia koreana (Korean stewartia)
Stewartia koreana, a close relative treated as a synonym or variety of S. pseudocamellia, opens broad camellia-like white flowers that spread flatter and more open.
Stewartia monadelpha (tall stewartia)
Stewartia monadelpha, a related species, wears smooth cinnamon-brown to tan flaking bark and grows to about 20 to 25 feet.
How to propagate
You can raise stewartia from seed or from cuttings, though neither is quick. Cuttings root in a few weeks and give the more dependable result, while seed is a slow crawl through a stubborn double dormancy.
SeedDemanding
Collect ripe seed in fall; seed requires warm then cold stratification and may take many months to germinate · 1 to 2 years or more to a transplantable seedling
Raising it from seed is slow work. The ripe seed, gathered in fall, must pass through a warm spell and then a cold one to break its double dormancy, which is why the small green shoots come up slowly and unevenly. Even after they surface, the seedlings need a year or two, sometimes more, to thicken into a plant sturdy enough to move.
Stem cuttingsModerate
Take softwood cuttings in early summer · Several weeks to root, then grow on for a season or more
Cuttings root faster. Soft green stem tips, taken in early summer and dipped in rooting hormone, throw out fine white roots within a few weeks under mist. The rooted cuttings then fill out for a season or more before they go into the ground.
Myths
Stewartia is just another kind of camellia.
The white, cup-shaped blooms really do echo a camellia's rounded petals, and both belong to the tea family. Even so, stewartia is a separate genus and a deciduous tree, and where a camellia keeps its glossy evergreen leaves, this one colors up and drops every leaf each fall.
Japanese stewartia is an easy, fast-growing shade tree.
It thickens and rises slowly, takes its time rooting into a new spot, and sulks when transplanted. Add its intolerance of drought, heat, and soggy ground, and it stands as a demanding tree, not an easy shade tree for beginners.