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Growing Pseudopanax
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Pseudopanax - Growing Guide

Growing Pseudopanax

These are evergreen trees and largeish shrubs from New Zealand. Some species go through a juvenile phase where their leaf forms are markedly different to those in maturity (P. crassifolius, P. ferox). They have an upright habit and are valued in gardens both for their foliage and fruits as well as architectural or unusual specimen plants. As such they have massively increased in popularity in recent years. In no small measure this is due to the increasing recognition of the hardiness of these unusual plants outdoors.

We have grown P. laetus outside at Burncoose and Caerhays both in full sun and in shade for over 30 years. It grows into a large rounded shrub of about 10-12ft in height with a similar spread. The huge palmate green leaves with five or seven ‘palms’ give this plant a genuinely tropical feel. That is not the end of the story either as, in winter, it produces huge umbrils (12-15in) of tiny greenish purple flowers. The flower heads then mature into equally huge clusters of purplish black fruits which remain as a feature on the tree all summer. Only the female plants produce seeds and our stockplants are female!

Pseudopanax seeds

P. arboreus, P. adantifolius and P. lessonii varieties are doing equally well in the garden. P. arboreus is just as vigorous and large growing as P. laetus. P. lessonii is more of a border shrub and makes a really good foliage effect in the greenhouse as well. These three species have not been through quite so many bad winters as P. laetus but they are certainly all proving frost hardy here. They grow more quickly in shade and certainly need wind protection as their large leaves can be damaged in storms.

P. crassifolius and P. ferox are very different. Slightly more tender as young plants they grow with us in warm sheltered glades in full sun. P. crassifolius has, at first, upright, diamond shaped or lance shaped blackish purple leaves. The plant then grows as a single stemmed, erect and unbranched small shrub with huge 1½-3ft long sword shaped dark leathery toothed leaves which hang down. After about seven to ten years the tree begins to branch at about 10-12ft in height and the leaves begin to change shape. Some remain sword-like but they are much smaller and some are three to five stalked leaflets. In final maturity the leaves become ‘simple’ again. They have no teeth and are a more uniform 3-8in long. There can be no other tree which changes its leaf form from simple to compound and to simple again during its life cycle. P. ferox has a similar life cycle as a tree but the leaves are smaller and mottled or even spotted brown, white and grey in juvenility. In full maturity they are green.

We have grown P. crassifolius to maturity at Caerhays surviving the odd scare when the tree needed staking to keep it upright as its top leaves matured. P. ferox has proved, so far, more difficult but both species grow perfectly well outside at Wisley. They have had less success at the Savill Gardens.

Plants of P. crassifolius and P. ferox should never be pruned. The other large leafed species may well get out of hand in the greenhouse and need a chop back. Pseudopanax respond positively to trimming and quickly reshoot however hard you cut them back.

Cuttings of the large leafed species are easy at any time of the year on bottom heat. They are slow to root and you may well want to halve the size of the leaves to avoid choking up the mist bench. Crassifolius is rather more difficult to root but best success comes from younger shoots on semi mature plants. There are no side shoots to make cuttings from on immature trees.

If you live in a colder area grow P. crassifolius and P. ferox in the greenhouse for as long as you can. They take up little room and you can admire the extraordinary leaves at close hand. Take the risk and try the others outside starting with P. laetus.