Blackboard tree
Alstonia scholaris (L.) R.Br.
The blackboard tree (Alstonia scholaris), also called scholar tree or milkwood, is a large evergreen of the dogbane family (Apocynaceae) with whorled leaves, night-fragrant white flowers and paired pendulous follicles; the bitter bark yields medicines and the soft wood once made school blackboards — a famous shade tree of Hanoi streets.
No ratings yet — be the first!
Gallery
Blackboard tree — Street trees on Trần Nhân Tông St, HanoiBlackboard tree — Tree
Blackboard tree — Leaves
Blackboard tree — Flowers
Blackboard tree — Fruit
Blackboard tree — BarkBlackboard tree — Street trees on Trần Nhân Tông St, HanoiBlackboard tree — TreeLife cycle
From seed to productTree
Large evergreen tree with straight bole and broad crown.
Leaves
Whorled oblong leaves, glossy above.
Flowers
Small white night-fragrant flowers in terminal cymes.
Fruit
Two slender pendulous pods; hairy wind-borne seeds.
Distribution & origin
Share of recorded occurrences by region- Southeast Asia (incl. Vietnam)30%
- India & Sri Lanka20%
- East Asia (China, Taiwan)15%
- Australia & Melanesia15%
- Planted across the tropics (Africa, Americas)20%
Chemical composition
Relative content in agarwood resin- Water55%
- Fibre & cellulose (wood, bark)25%
- Alkaloids (echitamine, alstonine)5%
- Tannins5%
- White latex5%
- Essential oils & aromatics5%
Uses
- Urban landscape: street shade tree, famously lining Trần Nhân Tông Street in Hanoi — the 'milk street'; rainy-season blooms scent the night air
- Wood: soft and light — formerly made school blackboards, pencils, crates and light boards; rarely used today as it is brittle
- Folk medicine: bark, leaves and latex against malaria, dysentery, asthma and inflammations; alkaloids studied for anticancer and antimicrobial activity
- Ecology: flowers feed pollinators, seeds spread by wind; low pest burden and easy to grow — suited to green streetscapes
Properties
- Form
- Large evergreen tree
- Product
- Blackboard/wood products; folk medicines
- Hallmark
- Whorled leaves; night-fragrant flowers; long paired pendulous pods
- Uses
- Shade tree, timber, medicine
Habitat & conservation
The blackboard tree is sun-loving and tolerates dry or poorly drained sites; it grows naturally in secondary forest, riparian and moist valley habitats of tropical Asia, and is now common along streets, in parks and schoolyards. In Vietnam it is frequent in Hanoi, Huế and Ho Chi Minh City; the milk trees of Trần Nhân Tông Street are a familiar summer sight.
Conservation
A widespread, adaptable species not under threat — classified as Least Concern (LC). Dogbane family (Apocynaceae), genus Alstonia — the same family as oleander and Gymnema.
References
- 1Plants of the World Online — Alstonia scholaris (L.) R.Br. — Kew Science, 2026
- 2Alstonia scholaris (blackboard tree, scholar tree, devil's tree) — description, distribution, uses — Wikipedia tiếng Anh, 2026
- 3Cây sữa (Alstonia scholaris) — cây bóng mát & thuốc dân gian — Vietnamese Wikipedia & urban greenery references, 2026
- 4黑板树 / 糖胶树 Alstonia scholaris — 形態、分布與用途 — Wikipedia tiếng Trung, 2026
- 5Nguồn ảnh: Forestowlet (CC0); Steve Fitzgerald (CC BY-SA 4.0) — Wikimedia Commons,
- 6Nguồn ảnh: Ltn12345 (CC BY-SA 4.0) — Wikimedia Commons,