Boswellia neglecta
| Light | Full sun to very bright light; the more light, the better the form |
|---|---|
| Water | Sparingly while in leaf; keep dry when leafless and dormant |
| Soil | Very sharp, mostly mineral mix (see Soil and potting mix) |
| Temperature | Frost-tender; keep warm and above freezing, USDA zones 10–11 |
| Propagation | Seed (best for a good caudex); cuttings possible but often rootier than fat |
| Toxicity | No serious toxicity reported; the aromatic resin can irritate skin and mucous membranes |
Boswellia neglecta is a small, drought-deciduous tree or shrub from the dry lands of East Africa, and one of the true frankincense species in the genus Boswellia. In habitat it can become a sizeable bush, but succulent collectors prize it as a caudiciform pachycaul: raised hard and lean, it develops a swollen, flared base and flaking, papery bark, releasing a fragrant resin when cut. It is sometimes sold under the common names frankincense or, loosely, black frankincense.
Description
Boswellia neglecta is a stem-succulent, drought-deciduous shrub or small tree. The trunk and lower branches thicken with age into a stout, often bottle-shaped base, above which the growth divides into a knot of twiggy, spreading branches. The bark is the great ornament of the species — thin, coloured in greys, coppers and reddish browns, and peeling away in fine papery flakes to reveal fresh tissue beneath.
The leaves are pinnate (divided into small leaflets) and carried only during the growing season; the plant sheds them and rests bare through drought and cold. Small, creamy white to pale yellow flowers appear in short sprays as the plant is coming back into leaf. All parts are aromatic, and a wound to the bark weeps the pale, gummy resin for which the frankincense trees are famous.
Distribution and habitat
The species is native to seasonally dry country in eastern Africa, across parts of Ethiopia, Somalia, Kenya and Tanzania and neighbouring areas. It grows in hot, open bushland and on rocky slopes, in gritty, sharply drained ground that bakes dry for much of the year and receives rain in a short, defined season. Plants there endure long droughts leafless, drawing on the reserves stored in their thickened stems.
Cultivation
Boswellia neglecta is a plant for the sunny, well-ventilated end of the collection, and its needs closely follow its wild rhythm. Give it as much light as you can — strong sun encourages a compact, fat-based plant, while shade produces thin, drawn growth. Use a very free-draining, largely mineral mix and a pot no larger than needed, and keep everything warm; the species is decidedly frost-tender.
Water is all about timing. Through the warm growing season, when the plant is in leaf, water thoroughly and then let the mix dry out before repeating. As the leaves yellow and drop, taper off and keep the plant dry and warm through its leafless rest — wet, cold roots on a dormant, bare-stemmed Boswellia are the surest route to rot. Many growers deliberately raise the caudex by planting a touch high and washing soil away from the base over successive repottings. See Watering for general technique.
Propagation
Seed is the best route to a well-shaped, thick-based plant. Fresh seed sown warm on a mineral surface germinates most reliably, and seed-grown specimens tend to build the fattest, most characterful bases over time; see Propagation — seed.
Cuttings will sometimes root, and are used to bulk up a desirable clone, but cutting-grown plants often stay comparatively slim and "leggy" rather than developing a proper swollen caudex. Take and callus them in the warm growing season and treat them as for other succulent cuttings.
Common problems
- Rot — the classic killer, almost always from watering a dormant, leafless plant or from a slow, water-holding mix. Keep it dry when bare and grow it hard.
- Etiolation — too little light gives thin, elongated shoots and a poorly defined base; move it to the brightest, sunniest spot available.
- Leaf drop out of season — usually a normal response to cold, drought or a check in conditions; the plant is simply going dormant early rather than dying.
- Pests — watch for mealybugs tucked into branch junctions and, in dry indoor air, spider mites; see Pests and diseases.
See also
- Boswellia — the genus overview and other frankincense species
- Caudiciform · Soil and potting mix · Watering · Repotting
- Propagation — seed · Propagation — cuttings