Longan
Dimocarpus longan
Steady warmth above 10°C matters here more than anything else the tree asks for.
- Type
- Fruit · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Sunlight
- Full sun, in the brightest corner of a heated greenhouse.
- Watering
- Freely through summer; in winter, less, though never bone dry.
- Feeding
- A balanced liquid feed every two weeks from spring to autumn.
- Frost tolerant
- Yes
- Flowering
- April
- Pruning
- Prune in spring to hold its size and shape.
- Overwintering
- Heated glass above 10°C, and less of everything through winter.
- Apr–May Flowering
- May–Sep Fruit Set
- Sep–Dec Harvest
- Jan–Apr Harvest
- Plant spacing
- 29 ft 6 in
- In-row spacing
- 29 ft 6 in
- Between rows
- 36 ft 1 in
- Square-foot density
- Not suited to SFG
- Root system
- Woody, shallow and far-reaching
- Working depth
- 12–24 in
- Can reach
- 4 ft down where the soil allows
- Spread
- 33–49 ft across, about 2–3× the width of the plant
Almost all of a tree’s roots are in the top two feet of soil, where the air is, and they run out well past the branch tips. The deep taproot most people picture belongs to the seedling; the tree grows out of it and spends the rest of its life spreading sideways instead.
The habit is Longan’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Mealybugs White cottony sap-suckers that gather in leaf axils and along stems, mostly on houseplants and under glass. Dab colonies with a cotton swab dipped in soapy water and isolate affected plants.
- Scale insects Immobile brown or white bumps fixed to stems and leaf undersides, sucking sap and weakening growth. Wipe off with a damp cloth or dab with horticultural soap; watch for the sooty mold that follows.
- Spider mites Red spider mite
- Root & crown rot Root rot from overwatering
- Sooty mold A black film growing on the honeydew left by aphids, scale, or whitefly above. Deal with the sap-sucking pest and sponge the leaves clean.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Ladybird (lady beetle) Coccinellidae
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Green lacewing Chrysoperla carnea
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Hoverfly Syrphidae
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Big-eyed bug Geocoris spp.Hunts Spider mites
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Minute pirate bug Orius spp.Hunts Spider mites
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Predatory mites Phytoseiulus & AmblyseiusHunts Spider mites
Fast orange mites that hunt spider mites egg-by-egg, and cousins that clear thrips and fungus-gnat larvae. Sold as a biological control for greenhouses; outdoors they follow humidity — mist and mulch, don’t dust with sulfur.
- Rove beetle StaphylinidaeHunts Spider mites
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
Green-leaved fruit, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com