We love big buttresses and we cannot lie! That is why August’s native plant of the month is pukatea. These lovely trees are wetland specialists that add a touch of the tropics with their glossy leaves and beautiful buttressed trunks.
Pukatea can be found throughout the North Island and in the very top of the South Island growing in swampy areas, beside streams and in rich deep soil on forested slopes. Seedlings prefer full or partial shade, but trees will happily grow up into the sun as long as their roots have some shade and plenty of moisture.
Pukatea are fantastic wetland specialist trees and make outstanding specimens for damp or boggy areas. Their fabulous skirts of buttress roots help stabilise their trunks in soft soil, much like the prop-roots of mangroves.
The roots’ raised ridges help the trees’ tissues breathe in wet conditions and sometimes individuals will even grow pneumatophores (snorkel roots, not a James Bond accessory) in very wet conditions. Pukatea bark is pale, almost white and trunks are often studded with raised bumps. These are lenticels - small pores of corky tissue that help with gas exchange, also helping the trees to breathe. Mature pukatea trees can grow up to 35m tall, although trees growing in the open will be much shorter than this.
Their canopies form billowing cumulo-nimbus shapes. Pukatea leaves are very glossy and dark green. They are edged with even, triangular teeth.
Pukatea flower in late spring and early summer with small green-yellow flowers. These flowers have nectar glands at their base which help attract the ants, beetles, native bees and flies that help pollinate them. Green vase- (or pokemon)- shaped fruit develop and split open in late summer to expose seeds with thick fluffy coats that enable them to fly off in the wind. With all the excellent work done by PFK volunteers to eradicate moth plant in Kaipātiki, perhaps there will be a day when the only fluffy, flying seeds we see will be pukatea and puawhananga?
Pukatea bark Pukatea flowers
As well as being beautiful, pukatea are useful. Their inner bark contains a compound similar to morphine called pukateine, and various concoctions of the bark were used to treat a range of medical needs by Māori.
Dried bark and leaves have been known to poison and kill sheep and rats, a reminder of the caution needed before using any plant medicine (and perhaps also suggesting a potential future research area in pest control uses). Pukatea timber was used by both Māori and pakeha for a range of items. The trees have reasonably soft wood that carves easily and this was often used for waka figureheads. Pukatea wood absorbs more than its own weight in water when immersed and is resistant to marine borer, making it useful for wharf pilings.
While pukatea are classified as Not Threatened, they have suffered from significant habitat loss over their entire range. The swampy lowland habitats that this species prefers are considered the best land for farming and horticulture. Many of our wetlands too have been drained for this reason, leaving pukatea standing high and dry and preventing the next generation of seedlings from germinating. So if you have a damp spot in your garden, or a reserve you are volunteering in, perhaps a pukatea would help make it that much more beautiful.