Acer henryi (Henry's Maple)
Acer henryi (Henry's Maple)
Introduction
Acer henryi, Henry's maple, is a Chinese species with trifoliate compound leaves — three separate leaflets on each petiole — creating an unusual maple character for bonsai. The compound leaves give it a lighter, more airy appearance than palmate-leaved maples. Autumn colour is a soft red-orange. It is uncommon in bonsai but offers a distinctive alternative.
Leaves are trifoliate — three elliptic leaflets 5-8 cm long on a common petiole. The compound leaf structure resembles negundo but with only three leaflets and a more refined appearance. Autumn colour is soft red-orange. Bark is smooth grey. Growth is moderate. The species is smaller than most maples, reaching only 10 m in the wild.
| Common Name | Henry's Maple | Family | Sapindaceae |
| Origin | Central China | Indoor/Outdoor | Outdoor |
| Bonsai Tradition | Emerging | Japanese Name | — |
| Difficulty | Intermediate | Group | Maple |
| Recommended Styles | Moyogi (Informal Upright), Shakan (Slanting), Hokidachi (Broom) | ||
| Size Categories | Chuhin (25–46 cm), Omono (46–76 cm) | ||
History & Tradition
Extremely rare in bonsai. Occasional specimens in Chinese collections. A collector's curiosity rather than a mainstream bonsai species.
About Maple Bonsai
Japanese maples are among the most popular deciduous bonsai, prized for their spectacular seasonal color changes and delicate leaf structure. From the fresh chartreuse of spring emergence through deep summer green to the fiery reds and golds of autumn, maples offer a living calendar. Leaf reduction through defoliation techniques can produce miniature leaves barely a centimeter across on well-developed trees. The fine ramification achievable on mature maple bonsai creates winter silhouettes rivaling the best deciduous trees in nature. Acer palmatum cultivars number in the hundreds, giving artists choices ranging from threadleaf dissectums to bold-lobed varieties. Maples prefer morning sun with afternoon shade protection and consistent moisture.
Botanical Profile
| Family | Sapindaceae | Genus | Acer |
| Species | henryi | Plant Type | deciduous |
| Origin | Central China | Growth Rate | moderate |
| Foliage Type | deciduous | Bark Character | grey, smooth |
| Autumn Color | red to orange | Height Range | 20-80 |
Named after Augustine Henry, the Irish botanist who collected extensively in China. Native to central China (Hubei, Sichuan). Hardy USDA zones 6-8. Belongs to section Negundo with negundo, sharing the compound leaf character.
Bonsai Styles
| Style | Japanese Name |
|---|---|
| Moyogi | Informal Upright |
| Shakan | Slanting |
| Hokidachi | Broom |
Informal upright works for the moderate growth. The trifoliate leaves create a distinctive canopy texture. Best at chuhin size where the compound leaves provide appropriate scale. Group plantings create unusual woodland effects.
Group Style Guide
Informal upright (moyogi) is the dominant style for Japanese maples, showcasing their natural graceful form. Broom style (hokidachi) is classical for maples, creating a rounded canopy on a straight trunk that displays autumn color spectacularly. Root over rock (sekijoju) exploits the maple's ability to develop dramatic surface roots gripping stone. Twin trunk (sokan) and clump (kabudachi) styles emphasize the forest-like quality of maple groves. Forest plantings (yose-ue) of maples are among the most popular group compositions. Cascade styles are rare for maples, as the species naturally grows upright.
Trunk & Nebari
| Nebari Development | moderate | Deadwood Suitability | not_suitable |
| Bark Scarring Risk | moderate | Bark Character | grey, smooth |
Standard development. Moderate growth rate. Air-layering works. The smooth bark is unremarkable but clean.
Deadwood Techniques
Not suited for deadwood. The smooth bark and moderate character do not invite deadwood work.
Wiring & Shaping
Aluminium wire. Standard techniques. The moderate growth is manageable.
| Wire Type | Bark Scarring Risk | Best Season |
|---|---|---|
| Aluminum | Lower (softer wire) | Late autumn / early spring |
| Annealed copper | Higher (holds shape better) | Late autumn / early spring |
🌍 Distribution Map
Native origin: Central China
Pruning & Pinching
| Ramification Quality | medium | Leaf/Needle Reduction | moderate |
Prune extending growth to maintain shape. Defoliation is possible but the compound leaves do not reduce in the same way as simple leaves. Manage opposite buds.
Watering
Standard maple watering. Consistent moisture. Not drought-tolerant.
Soil & Repotting
| Substrate Type | Standard Akadama Mix |
| Repotting Frequency | Every 2 years |
| Root Pruning Tolerance | moderate |
Standard maple mix. Repot every 2-3 years. Not demanding.
Group Soil Recipes
Deciduous maple substrate should retain more moisture than conifer mixes: 60% akadama, 20% pumice, 20% lava rock or perlite. The higher akadama ratio supports the moisture needs of large-leafed deciduous trees. Particle size of 2–5 mm works well for most sizes. Repot every 2–3 years in early spring before bud break. Root pruning can be aggressive on healthy maples, removing up to 50% of the root mass. A thin layer of sphagnum moss on the soil surface helps maintain even moisture during hot summers.
Fertilizing
| Season | NPK Ratio | Frequency | Notes |
|---|---|---|---|
| Spring | 10-10-10 | Every 2 weeks | Support new growth |
| Summer | 10-10-10 | Every 2 weeks | Sustain vigor |
| Autumn | 0-10-10 | Every 3–4 weeks | Harden off for winter |
| Winter | None | — | No feeding during dormancy |
Standard balanced feeding. Not demanding.
Light & Placement
Partial shade to full sun. Handles moderate conditions.
Seasonal Placement Guide
Spring: Watch for bud break; protect emerging leaves from late frost; apply dilute fertilizer after leaves harden off. Summer: Partial defoliation in early summer for leaf reduction on strong trees; protect from scorching afternoon sun; maintain consistent moisture. Autumn: Enjoy the color display; reduce fertilizer; leaves drop naturally — remove fallen leaves from soil surface. Winter: Protect roots from hard freezes below -5°C; prune heavy branches during dormancy when sap is down; seal large cuts with wound paste.
Seasonal Care
| Season | Watering | Feeding | Key Tasks |
|---|---|---|---|
| Spring | Increasing | Resume / increase | Repotting, structural pruning, wiring |
| Summer | Maximum | Regular biweekly | Maintenance pruning, pinching, pest watch |
| Autumn | Decreasing | Reduce / stop | Wiring, structural work, winter preparation |
| Winter | Minimal | None (dormancy) | Protect roots, plan next season |
Standard deciduous bonsai care. Autumn: Soft red-orange colour. Winter: Hardy to zone 6.
Group Seasonal Guide
Spring: Watch for bud break; protect emerging leaves from late frost; apply dilute fertilizer after leaves harden off. Summer: Partial defoliation in early summer for leaf reduction on strong trees; protect from scorching afternoon sun; maintain consistent moisture. Autumn: Enjoy the color display; reduce fertilizer; leaves drop naturally — remove fallen leaves from soil surface. Winter: Protect roots from hard freezes below -5°C; prune heavy branches during dormancy when sap is down; seal large cuts with wound paste.
Pests & Diseases
Generally healthy. Standard maple issues. Few specific pests.
Group Pest Guide
Aphids frequently colonize new growth in spring, causing leaf curl and sooty mold; treat with insecticidal soap or systemic insecticide. Powdery mildew appears as white patches on leaves in humid conditions; improve air circulation. Verticillium wilt is a serious fungal disease causing branch dieback; no cure exists, but affected branches can be removed. Scale insects occasionally appear on branches; treat with horticultural oil. Leaf scorch from hot sun or wind is cosmetic but stressful; provide afternoon shade protection.
| Pest/Disease | Identification | Treatment |
|---|---|---|
| Aphids | Clusters on new growth, sticky honeydew | Insecticidal soap, water spray, ladybugs |
| Scale Insects | Brown or white bumps on stems/branches | Horticultural oil, systemic insecticide, manual removal |
| Mildew | Check foliage and stems | Consult specialist resources |
Propagation
Seeds after stratification. Air-layering works. Cuttings moderately successful. Limited availability.
Group Propagation Guide
Japanese maples propagate readily from seed collected in autumn. Fresh seed requires 90–120 days cold stratification. Named cultivars must be propagated by grafting or air layering, as seedlings vary. Air layering in spring produces rooted sections within one growing season. Softwood cuttings taken in early summer can root under mist propagation. Approach grafting in spring is used for specialized cultivars. Ground layering of low branches produces new plants while maintaining the mother tree. Seedlings take 3–5 years to reach initial training size.
| Method | Timeline | Notes |
|---|---|---|
| Seeds | Variable | Consult species-specific guides |
| Air Layering | 8–12 weeks | Instant thick trunk; advanced |
Size Classification
Best at chuhin to medium sizes. The trifoliate leaves create acceptable scale at 30-60 cm tree size.
| Keshitsubo (3–8 cm) |
| Shito (5–10 cm) |
| Mame (5–15 cm) |
| Shohin (15–20 cm) |
| Komono (15–25 cm) |
| Chuhin (25–46 cm) ✅ |
| Omono (46–76 cm) ✅ |
| Dai (76–122 cm) |
| Imperial (122+ cm) |
Varieties & Cultivars
No widely available cultivars. The species itself is the ornamental form.
Group Varieties
Acer palmatum is the primary bonsai maple with hundreds of cultivars. Deshojo has brilliant red spring growth. Kiyohime is naturally compact with fine ramification. Seigen offers red spring and autumn color. Acer buergerianum (trident maple) has superior trunk development and tolerates more sun. Acer ginnala (Amur maple) is extremely cold-hardy. Mountain maple (A. campestre) suits European collections. Dissectum cultivars with thread-like leaves create weeping bonsai forms. Coral bark maple (Sango-kaku) offers year-round red branch color.
Buying Guide & Display
Very difficult to source — specialist botanical nurseries or seed exchanges are the best options. Not commercially available as bonsai material.
| Check | What to Look For |
|---|---|
| Trunk | Good taper, interesting movement, no reverse taper at graft union |
| Nebari | Even radial root spread, no circling or crossing roots |
| Roots | Healthy white root tips visible, no root rot smell |
| Branches | Well-placed primary branches, no large scars or stubs |
| Health | Vibrant foliage color, no pests, firm bark, strong buds |
Troubleshooting
Few specific problems. Leaf reduction is limited with compound leaves. Accept the natural leaf character rather than fighting it.
Common Problems
Display & Exhibition
Display to highlight the trifoliate leaf character — unusual and conversation-worthy. Simple pots that do not distract from the unusual foliage.
Group Display Guide
Autumn is the prime season for maple bonsai display, when foliage color creates maximum visual impact. A light-colored oval or rectangular pot in unglazed or subtle grey-blue glaze complements autumn colors. The display stand can be lighter in style than conifer stands, reflecting the tree's delicate character. Spring display showcases fresh green leaves; winter display reveals the branch structure and ramification. A water stone or autumn-themed scroll enhances the seasonal composition. Avoid display in direct sunlight, which fades autumn colors prematurely.
Frequently Asked Questions
How often should I water my Henry's Maple bonsai?
Water your Henry's Maple bonsai when the top layer of soil begins to dry. During summer this may be daily or even twice daily for outdoor trees; in winter, reduce frequency significantly. Always water thoroughly until water runs from the drainage holes, then allow the soil to partially dry before the next watering.
Can I keep Henry's Maple bonsai indoors?
No. Henry's Maple is an outdoor species that requires natural sunlight, air circulation, and seasonal temperature changes including winter dormancy. Growing it permanently indoors will weaken and eventually kill the tree.
What bonsai styles suit Henry's Maple?
Henry's Maple is particularly well-suited to Moyogi, Shakan, Hokidachi. Choose a style that complements the existing trunk movement and natural growth habit of your individual tree.
When should I repot my Henry's Maple bonsai?
Repot Henry's Maple every 2 years in early spring, just before the buds begin to swell. Signs that repotting is needed include water sitting on the surface without soaking in, roots circling inside the pot, or reduced vigor despite proper care.
How do I wire Henry's Maple bonsai?
Use aluminum wire for Henry's Maple. Apply wire at a 45-degree angle, with wire thickness approximately one-third of the branch diameter. Wire during the dormant season when possible, and check wires every 2–4 weeks during the growing season to prevent them cutting into the bark.
Is Henry's Maple good for beginners?
Henry's Maple has a difficulty level of intermediate. While not the easiest species, it rewards careful attention to watering and seasonal care.
What soil mix should I use for Henry's Maple?
Use a well-draining bonsai mix for Henry's Maple. The key principle is excellent drainage combined with adequate moisture retention. Never use standard garden soil or purely organic potting mix for bonsai, as these compact over time and suffocate roots.
How do I promote ramification on Henry's Maple?
Ramification on Henry's Maple is rated as medium. Promote finer branching through repeated cycles of growing and cutting back. Allow shoots to extend 4–6 nodes, then prune back to 1–2 nodes. Over multiple growing seasons, this creates increasingly dense and refined branch structure.
When is the best time to prune Henry's Maple?
Perform structural pruning on Henry's Maple during the dormant season (late autumn to late winter) when the tree's energy reserves are in the roots. Maintenance pruning and pinching of new growth can be done throughout the growing season to maintain shape and promote density.
How cold-hardy is Henry's Maple?
Henry's Maple requires winter dormancy and tolerates cold well, but container-grown bonsai need root protection from sustained hard freezes below -5°C. Hardy in USDA zones 6-9. Protect container roots by placing in an unheated garage, cold frame, or burying the pot in ground soil during extreme cold.
Quick Reference Summary
| Scientific Name | Acer henryi |
|---|---|
| Common Name | Henry's Maple |
| Family | Sapindaceae |
| Origin | Central China |
| Group | Maple |
| Indoor/Outdoor | Outdoor |
| Difficulty | Intermediate |
| Bonsai Tradition | Emerging |
| Wiring Suitability | good |
| Wire Type | aluminum |
| Ramification | medium |
| Leaf/Needle Reduction | moderate |
| Nebari Development | moderate |
| Deadwood Suitability | not_suitable |
| Substrate | — |
| Repotting Frequency | Every 2 years |
| USDA Zones | 6-9 |
