Australian flame tree, Brachychiton acerifolius. (Photo by Joshua Siskin)
I have always had a soft spot for the Kurrajong tree, perhaps because of its Siberianised trunks, distinctive leaves, bell-shaped flowers with scalloped edges or the seeds packed tightly in woody cysts that look like ears of corn.
Kurrajong is an Aboriginal word for fishing line. Fishing lines are sometimes made from the fibres of the trunk. The botanical genus name for these trees is Brachychiton, a combination of the Greek words brachys (short) and chiton (covering), in reference to the rind that covers the seeds. These seeds are commonly roasted and then eaten.
There are several species of what are called bottle trees in Kurrajong, but the most striking is the Queensland Bottle Tree (Brachychiton rupestris), the trunk of which resembles a bottle in its early growth, but in 7 to 10 years becomes bulbous or barrel-like, the central bulge of the trunk eventually reaching a diameter of 11 feet, although in a dry climate such as ours it rarely ever reaches a height of more than 30 feet.
The trunk resembles a bottle not only when young, but throughout its life, taking into account its water-holding capacity. This species can be uprooted and left for three months without worrying about drying out. If transplanted after a period of dormancy where the roots no longer touch the ground, it will quickly show signs of new growth. In times of drought, it is summer deciduous, shedding its leaves during this season. The species name rupestris means rock, indicating that it can grow in rocky soils with poor drainage. Its beautiful, narrow leaves, reminiscent of willow leaves, provide a sophisticated contrast to the stocky appearance of the trunk.
The more common, and less dramatic, bottle tree resembles the leaves of a poplar tree, hence its scientific name, Brachychiton populneus. This species is widely planted as a street tree due to its columnar growth habit and roots that grow straight down so that they have no problem lifting up the sidewalk. The Australian flame tree (Brachychiton acerifolius) produces a profusion of brilliant scarlet flowers that no other tree flowers. Finally, the lacebark or pink flame tree (Brachichyton discolor) is famous for its large clusters of salmon-pink flowers.
All four of the trees mentioned above can be seen in the Australian section of the Los Angeles County Botanical Gardens in Arcadia.
The bottle tree belongs to the Hibiscus family (Malvaceae), which also includes several other famous trees, one of which is the Baobab, made famous by the children's classic The Little Prince, and the other is the cocoa tree (Theobroma cacao), from whose so-called beans (actually the seeds) chocolate is made.
The best-known ornamental tree in this family is the kapok (Ceiba/Chorisia speciosa). Native to Brazil, this unusual tree is known primarily for its distinctive trunk, which is covered with soft, pea-green bark and large, stubby, deterrent thorns for much of the year. These thorns also keep Amazonian animals, especially monkeys, from gnawing at the trunk. The thorns also collect dew, which condenses into water that runs along the thorns to their sharp tips, from where it drips into the soil below, a strategy that helps the tree sustain itself during extended droughts.
The star-like flowers of the albicilla julibrissin bloom in late summer, followed by football-sized fruits that soon split open to reveal a fluffy, silky fiber called kapok that can be used to stuff pillows and cushions.
Until the advent of synthetic fibers in the 1950s, kapok, being extremely light and highly hydrophobic, was used exclusively as stuffing for life jackets, and as the interior stuffing for every automobile manufactured in the U.S. Entire plantations of floss silk trees in East Asia were cultivated for kapok production.
Floss silk trees are deciduous and conveniently shed their leaves just before flowering. In their rainforest habitat, the leaves fall, making the flowers more accessible to pollinating bats. Floss silk seeds attach to kapok fibers, aiding in long-distance seed dispersal. Floss silk trees have become naturalized in West Africa because of kapok's buoyancy and water repellency; the fibers with embedded seeds drifted across the ocean from South America. The tree can grow to be as large as 60 feet tall, but Pink Princess is a dwarf cultivar that only grows to 12 feet tall.
California Native Plant of the Week: The fastest growing of California native plants is the Island Tree Mallow (Lavatera assurgentiflora), a member of the hibiscus family. Native to Santa Catalina and Santa Barbara Islands, it makes an easy hedge screen. Plant seeds in a sunny spot in the fall and the seedlings will grow to 10 feet tall within a year. It flowers on and off throughout the year, but most blooms in the spring and summer. The flowers are deep pink to lavender, pinwheel-shaped, and each petal is striped with white. The maple-leaf-like leaves can be dull to vibrant green, depending on the microclimate, watering regime, and season. The California Tree Mallow is structurally weak, and if not pruned regularly, the branches will break as it ages. The plant is available at Tree of Life Nursery (californianativeplants.com) in San Juan Capistrano.
Send your questions, comments, gardening woes and success stories to Joshua@perfectplants.com If you have a rare or exotic plant that most people don't know about, or if you grow a familiar plant in a unique way, we'd love to hear about it and share your experience here.
