What hardiness zones is Stewartia monadelpha suitable for?

Stewartia monadelpha is suitable for USDA hardiness zones 5, 6, 7, 8.

What are the sun requirements for Stewartia monadelpha?

Stewartia monadelpha requires Part Sun.

How much water does Stewartia monadelpha need?

Stewartia monadelpha has Medium water needs.

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Broadleaf Deciduous Trees

Stewartia monadelpha

tall stewartia

TheaceaeJapan and Korea

At a Glance

TypeTree

HabitUpright

FoliageDeciduous

Height20-30 feet (6-9 m)

Width15-20 feet (4.6-6 m)

Maturity20 years

Growing Zones

USDA Hardiness Zones

5 - 8

Zone 5

Zone 6

Zone 7

Zone 8

These zones indicate the coldest temperatures this plant can typically survive.

Frost Tolerancehardy

Key Features

Attracts Pollinators

Deer Resistant

Maintenancevery low

Overview

Stewartia monadelpha is a deciduous tree reaching 20-30 feet (6-9 m) tall in cultivation (taller in the wild) with a spread of 15-20 feet (4.6-6 m), developing an upright, somewhat columnar to narrowly pyramidal form — narrower than S. pseudocamellia. Bark is the primary ornamental feature: smooth, exfoliating in thin, papery flakes to reveal a polished cinnamon-brown to rich reddish-brown underlayer, becoming increasingly spectacular with age. The bark is often described as the finest of any deciduous tree. Leaves are alternate, simple, elliptic to ovate, 1.5-3 inches (4-8 cm) long, finely serrate, dark green, turning orange to bronze-red in fall. Flowers are white, camellia-like, 5-petaled, 1-1.5 inches (2.5-4 cm) across — smaller than S. pseudocamellia — with fused (monadelphous) violet-purple stamens, borne singly along the branches in June to July. The species name 'monadelpha' refers to the fused stamen filaments. Growth rate is slow at 6-12 inches (15-30 cm) per year. Resents transplanting; establish in permanent location when young. The Pacific Northwest's maritime climate with cool, moist summers and acidic soils provides ideal growing conditions.

Native Range

Native to Japan and Korea, occurring in moist montane forests at moderate elevations. The species grows taller in the wild (to 80 feet / 25 m) than in cultivation.

Suggested Uses

Planted as a specimen or focal point where the exceptional bark can be appreciated at close range, spaced 15-20 feet (4.6-6 m) from other trees. The narrow, upright form fits into smaller spaces than S. pseudocamellia. Site near paths, patios, or windows where the bark can be observed year-round. Effective as an understory tree at woodland edges. Combines well with rhododendrons, Japanese maples, and other acid-loving plants. The bark is most visible and dramatic when illuminated by low winter sun.

How to Identify

Identified by smooth, exfoliating cinnamon-brown to reddish-brown bark, narrowly upright form, small white camellia-like flowers with distinctive violet-purple fused stamens, and dark green elliptic leaves. Distinguished from S. pseudocamellia by narrower, more upright form, smaller flowers (1-1.5 vs 2-3 inches), smoother and more uniformly cinnamon-colored bark (vs patchwork mosaic), and violet-purple (not yellow) stamens. The monadelphous (fused) stamens are diagnostic.

Appearance

Size & Dimensions

Height20' - 30'

Width/Spread15' - 20'

Reaches mature size in approximately 20 years

Colors

Flower Colors

white

Foliage Colors

green

Fall Foliage Colors

orange

red

Bloom Information

Bloom Period

~4 weeks

Summer

White camellia-like flowers with violet-purple fused stamens appear singly along branches in June to July, lasting 3-4 weeks. Individual flowers last 1-2 days but open sequentially over the bloom period. Flowers are smaller than S. pseudocamellia but the violet-purple stamens add a distinctive color accent. The bark display is year-round and is the primary ornamental feature.

Detailed Descriptions

Flower Description

White with violet-purple stamens

Foliage Description

Dark green

Growing Conditions

Sun Requirements

Full Sun

Partial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 6.5(Acidic)

357912

Soil Types

loampeat

Drainage

well drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

8-15 years

Care & Maintenance

Care Guide

Water regularly; stewartias require consistent moisture, particularly during the first 3-5 years. Mulch 3-4 inches (8-10 cm) with organic matter. Plant in part shade to full sun; afternoon shade is beneficial in warmer locations. Requires acidic, moist, well-drained soil rich in organic matter — conditions naturally present in much of the Pacific Northwest. Resents transplanting; establish in a permanent location from a container-grown plant. Protect from hot, drying winds. Essentially pest- and disease-free when properly sited.

Pruning

Minimal pruning needed. Establish a central leader in youth. Remove crossing and dead branches in late winter. Avoid heavy pruning; stewartias have a naturally elegant form that should be maintained. Do not remove lower branches unless necessary — the bark display on the trunk and lower limbs is the primary ornamental feature. If branches must be removed, prune in late winter.

Pruning Schedule

winter

Maintenance Level

very low

⚠️ Toxicity Warning

Non-toxic