Treefern: Cibotium

• Cibotium
  A relatively small genus of magnificent tree ferns from Central America, Hawaii and Southeast Asia; not formerly included because they are generally not particularly cold-hardy. However, I did recently hear about someone overwintering the spectacular Hawaiian C. menziesii in the cool climate of Britain, and so decided this genus deserved a little more attention. Cibotium is closely related to Dicksonia.

Cibotium chamissoi-This species is a large, beautiful tree fern with an upright habit. Its cold-hardiness, I would speculate, may be intermediate between that of C. menziesii and C. glaucum. Apparently it forms suckers on the trunk resulting in multiple crowns.

Cibotium glaucum-This large tree fern with leathery fronds is native to Hawaii and can occasionally be found for sale in California. Although the trunk usually does not surpass 12' tall, the beautiful arching fronds can reach a great length. It seems to be able to handle a degree or two of frost without protection, and there may be some large specimens outdoors in sheltered California gardens. It is probably not unlike C. menziesii in its requirements in cultivation, but one reference suggests it is even less cold-hardy. Any attempt to grow it outdoors in zone 8 or 9a would require elaborate winter protection measures, as temperatures more than a couple degrees below freezing would likely be the death of it.

Cibotium menziesii-Cibotium menziesii is probably the hardiest of the Hawaiian Cibotiums, although I am not certain how its hardiness compares to that of C. schiedei. It has a very large, upright crown of fronds, a good one to walk under even if the trunk is short. The stipes are slightly glaucous and uncurling croziers are covered in a brown tomentum.
Despite its tropical origins, it seems able to withstand long, cool winters without its fronds, and it does not require a great deal of heat to begin new growth--a remarkably adaptable plant. One fellow overwintered this species through a temperature of 14°F in England by packing straw bales around his plant. I am therefore optomistic for its potential in similarly cool climates such as that of the Pacific Northwest. It should adapt to hot as well as cool climates, and is also worth trying throughout the Southern United States if appropriate protection measures are taken.

Cibotium schiedei -"Mexican Tree Fern" This species is a small to moderate sized tree fern, easily recognized by its long, arching and drooping light green fronds with elongated pinnae. It can reach 12' tall over time, but trunk development is quite slow; and the fronds may be as long as 10' in favorable situations. Like C. menziesii, the lower stipes are covered with brownish fuzz. The croziers are covered with silky white fuzz. Older plants send up offshots like some species of Dicksonia, untimately forming a clump of treeferns if the offshoots are not removed.
Cibotium schiedei is very easy to grow, and, though it thrives in a shady, damp area, it will tolerate a wide range of conditions. It is also well adapted to pot culture. Its hardiness is reputed to be around 25°F, and it also grows well in cool temperatures. It should make a suitable specimen with winter protection in at least zones 8b and up.

Other species of Cibotium

Cibotium barometz (Southeast Asia)-A small Cibotium that forms little or no above-ground trunk. Has reportedly withstood 24°F in Australia. There are two other species from Southeast Asia which might or might not be as hardy.

Cibotium regale (Mexico)-This species is likely to be rather difficult to grow outside the tropics, but is still worth trying. The beautiful deep-bluish green fronds are rather triangular and held in a very attractive habit with drooping tips. Trunk development is slow, but the trunk can eventually reach 12' tall, with a crown spread of 16'. It requires lots of shade, moisture and protection from wind.

Thank: angelfire.com