This remarkable New Zealand tree is only hardy in the maritime counties of the south and west. It is evergreen and in the wild grows 20 to 50 ft high. The leaves are extraordinarily variable according to the age and development of the tree, and Cheeseman describes them in four distinct stages. At the first or seedling stage they are 1 to 2 in. long, diamond-shaped or ovate-lanceolate, tapered at the base, coarsely toothed or lobed. At the second and most remarkable stage the plant is a straight, erect, unbranched, slender stem, bearing the leaves on the upper part; they are then sword-shaped, very stiff, deflexed, often 11⁄2 to 3 ft long but only 1 to 2 in. wide, of very leathery texture, the margins armed with large sharp teeth. At the third stage, when the tree begins to branch, the leaves are erect or spreading, some of them divided into three or five stalkless leaflets, whilst others retain the No. 2 shape but are only one-third as long. At the fourth or mature stage they become simple leaves again, 3 to 8 in. long, 1 to 11⁄2 in. wide, linear to linear-obovate, either without teeth or toothed towards the apex and tapered at the base to a stout stalk 1⁄2 to 1 in. long. Sometimes the third stage is omitted and the tree never bears compound leaves. It is at that stage trees commence to flower, the sexes on different ones. The blossoms are small, of no beauty, produced in terminal compound umbels 3 or 4 in. across. Fruits globose, black, 1⁄5 in. wide.
There is a specimen of this araliad approaching the third stage at Wakehurst Place, Sussex, 27 ft high and 11⁄2 ft in girth (1969). This is in the Valley. Two examples by the Heath Garden are at the second stage. Trees with two or more distinct types of leaves are very characteristic of the New Zealand flora, but in none is the diversity more remarkably developed than in this. The species was originally discovered during Cook’s first voyage (1769-70).
P. ferox (Kirk) Kirk Panax ferox Kirk – In this related species the leaves of the second stage (see above) are deflexed as in P. crassifolius and of similar shape, but are edged with broad-based lobules, roundish at the apex and usually equipped each with a sharp hook. The adult leaves are rather shorter than in P. crassifolius – up to about 6 in. long. A further distinction in wild plants is that the fruits are larger – about 3⁄8 in. wide (little more than half that in P. crassifolius). It is a native of both islands of New Zealand, but is found at lower elevations than P. crassifolius.