Fouquieria
Fouquieria is a small genus of spiny, drought-deciduous desert shrubs and pachycaul trees native to the arid regions of the American Southwest and Mexico. It is the only genus in the family Fouquieriaceae, and includes some of the most striking silhouettes in the desert flora — the whip-like ocotillo (Fouquieria splendens) and the surreal, upturned-carrot form of the boojum tree (Fouquieria columnaris). Though woody and shrub-like rather than fleshy, several species store water in swollen stems and are grown by succulent enthusiasts as caudiciform or pachycaul curiosities.
Description
Members of Fouquieria share a distinctive growth strategy suited to unpredictable desert rainfall. Most are woody, spiny plants whose stems are lined with stout thorns; in the typical ocotillo group these emerge as clusters of tall, cane-like branches from a short basal trunk, while the pachycaul species (such as the boojum and F. fasciculata) develop a thickened, water-storing trunk that can become massive with age.
The defining trait of the genus is that they are drought-deciduous. After rain, small oval leaves flush rapidly along the stems; as the soil dries the leaves are shed, and the plant waits out drought as a bundle of bare, thorny wands. Many species can leaf out and drop several times in a single year in response to rainfall. The thorns themselves are the hardened, persistent petioles of the first leaves of each flush — a neat piece of desert economy, as later fascicles of leaves emerge from a bud at the base of each spine.
Flowering is showy. Tubular blooms, most often in vivid reds and oranges but sometimes cream or yellow, are borne in clusters at the branch tips and are much visited by hummingbirds and, in some species, bats.
Distribution
The genus is centred on Mexico, with its greatest diversity in the arid interior and along the Baja California peninsula. F. splendens ranges most widely, extending north into the Sonoran, Chihuahuan and Mojave deserts of the southwestern United States (Arizona, New Mexico, Texas and California). The boojum, by contrast, is a narrow endemic of the fog-influenced deserts of Baja California and a small pocket of coastal Sonora. Plants typically grow on rocky slopes, desert flats and thornscrub in fast-draining, mineral soils.
Notable species
- Fouquieria splendens — the ocotillo, a fountain of tall spiny canes topped with scarlet flowers; the most familiar species and the emblem of the Sonoran and Chihuahuan deserts.
- Fouquieria columnaris — the boojum tree (cirio), a slow-growing pachycaul whose tapering trunk can reach great heights, sometimes bending and forking into fantastical shapes.
- Fouquieria fasciculata — a prized caudiciform species with a swollen, fissured trunk, popular with collectors of fat-stemmed plants.
- Fouquieria macdougalii — the tree ocotillo, forming a distinct trunk topped with ocotillo-like branches and free-flowering in cultivation.
- Fouquieria diguetii — a branching, tree-like ocotillo of Baja California and Sonora with red tubular flowers.
Cultivation
Fouquieria are grown much like other desert succulents, with an emphasis on sharp drainage and strong light. Give them a very free-draining, mostly mineral mix and the brightest position available — these are full-sun desert plants and will sulk in shade. Water generously during the warm growing season while the plant is in leaf, then reduce sharply once it drops its leaves and enters dormancy; keep them dry and, ideally, cool through winter. Overwatering a leafless, dormant plant is the surest way to rot it. See Watering and Repotting for general technique.
A quirk worth knowing: freshly transplanted plants, especially bare-root ocotillo, can be slow and reluctant to re-establish, sometimes sitting dormant for months before roots take hold. Patience and restraint with the watering can go a long way. Most species are frost-sensitive and are best protected from hard freezes, though established F. splendens tolerates light frost in dry conditions.
Hobby and cultivar notes
For succulent and caudiciform collectors, the pachycaul species — the boojum, F. fasciculata and F. macdougalii — are the main draw, valued for their sculptural, water-storing trunks rather than for named cultivars, of which the genus has few. These are slow, long-lived plants that reward a hands-off approach.
Propagation is chiefly by seed, which is the reliable route for the pachycaul species and produces the best-formed trunks. Ocotillo (F. splendens) is also commonly established from large stem cuttings pushed directly into the ground, a traditional method used to make living fences, though success can be hit-or-miss. Wild-collected ocotillo is widely sold for landscaping; buyers should seek nursery-propagated or legally salvaged stock, as digging plants from the wild is regulated in parts of the range.
See also
- Fouquieria splendens · Fouquieria columnaris · Fouquieria fasciculata
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — cuttings
- Pests and diseases