Bursera microphylla
| Light | Full sun to very bright light; loves heat |
|---|---|
| Water | Deeply but infrequently in the warm growing season; keep dry during winter dormancy |
| Soil | Fast-draining, gritty mineral mix (see Soil and potting mix) |
| Temperature | Frost-tender; keep above about 5 °C, USDA zones 9b–11 |
| Propagation | Seed; hardwood cuttings (variable success) |
| Toxicity | No specific toxicity data; not known to be dangerously toxic, but the aromatic resin can irritate skin |
Bursera microphylla, the elephant tree or torote, is a small caudiciform tree of the Bursera genus native to the deserts of the southwestern United States and northwestern Mexico. Prized among succulent growers for its swollen, tapering trunk, papery peeling bark and delicate fern-like leaves, it makes a striking natural bonsai and fills the air with a sweet resinous scent when its foliage or bark is bruised.
Description
Bursera microphylla is a stout, slow-growing tree that in habitat reaches a few metres tall but is usually kept far smaller in cultivation. Its most distinctive feature is the thick, water-storing trunk and lower branches, which taper abruptly like an elephant's leg and give the plant both its common name and its appeal as a caudiciform succulent. The pale, papery bark peels in thin sheets to reveal a greenish, photosynthetic layer beneath, an adaptation that lets the trunk keep working even when the plant is leafless.
The leaves are small and pinnate, made up of many tiny leaflets that give the whole crown a soft, ferny texture. They are drought-deciduous — dropped in dry spells and through the cool season, then flushed again with warmth and moisture. Small cream to yellowish flowers appear in the warm months, followed by little three-parted fruits. Every part of the plant is aromatic, exuding a fragrant resin that has long been valued locally.
Distribution and habitat
The elephant tree grows across the Sonoran Desert region, from southern California and Arizona in the United States south through Baja California, Sonora and neighbouring parts of Mexico. It favours rocky desert slopes, washes and canyon walls, often anchoring into cracks in bedrock where its swollen base can hoard the little water available. Plants here endure intense heat, blazing sun and long droughts, contracting through the dry season and leafing out opportunistically after rain.
In the northern part of its range it is uncommon and slow-growing, and wild elephant trees are best admired and left in place rather than collected.
Cultivation
Bursera microphylla is a rewarding subject for growers who can give it heat and restraint. Plant it in a very free-draining, mostly mineral mix and site it in the brightest, warmest spot available — full sun suits it well and encourages the compact, thickened growth that shows off the caudex. During the warm growing season water deeply once the mix has dried, and feed lightly; the plant responds to warmth and moisture by pushing fresh ferny foliage.
The critical rule is a dry winter rest. As temperatures fall and daylight shortens the tree naturally drops its leaves and goes dormant; at this point withhold water almost entirely and keep it warm and dry, as cold wet roots are the quickest way to lose it. Protect from frost at all times. Grown hard and bright, the trunk fattens over the years into a characterful bonsai-like form. See Watering and Repotting for general technique.
Propagation
Seed is the most reliable route to a well-formed, naturally swollen trunk, though germination can be slow and erratic; sow onto a warm, gritty surface and be patient. Hardwood cuttings will sometimes strike, offering a faster head start, but cutting-grown plants tend to root shallowly and often lack the fat tapering base that makes seed-raised specimens so prized. See Propagation — seed and Propagation — cuttings for full walkthroughs.
Common problems
- Rot — by far the commonest cause of loss, almost always from watering during dormancy or from a slow-draining mix; the trunk softens and discolours.
- Leaf drop — normal and seasonal; sudden drops can also follow cold, drought stress or a move, and are usually recovered from once conditions improve.
- Slow or reluctant growth — often simply too little heat and light; this is a sun-loving desert plant that sulks in cool, dim conditions.
- Pests — mealybugs and spider mites may appear under glass; see Pests and diseases.
See also
- Bursera — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — cuttings