The park features alpine herb and mossfields, scree, high-altitude grasslands, tangled “leatherwood” shrubland, bluffs, steep bouldery rivers, swamps, tarns, a lake and extensive unlogged podocarp, cedar and hardwood forests (especially rata and kamahi trees).
The forests are composed of native conifer and broadleaved tree species, with beech trees notably absent. Other outstanding features are the large number of northern rata trees and one of the most extensive kahikatea-rimu-kāmahi semi-swamp forests in the North Island.
Another unusual type of vegetation found in the park is the high-altitude kāmahi forest known as the ‘Goblin Forest’. Located near Dawson Falls it is famous for its distinctive gnarled and intertwined trunks growing around old dead trees. When volcanic eruptions destroyed large areas of rimu forest about 400 years ago, kämahi became the dominant species here. Many of the kāmahi trees are growing on old tōtara and rata trees destroyed by the eruptions.
The lowland coastal forest of the Kaitake Range is a very different forest than is found in the rest of the Egmont National Park. The trees here are not found in the higher areas.There are nikau, titoki, kohekohe,and puriri trees. You’ll find pukatea and karaka trees and see silver fern and a range of smaller plants. A stand of Californian redwood trees, planted in the 1930s are protected by a special dispensation in the Egmont National Park Management Plan. Other exotic trees planted at the same time are slowly being removed to allow regeneration of native species.
A third of the park’s plant species are found in a small area of swampland called Ahukawakawa, which lies between the main cone and the Pouakai Range. The area forms the headwaters of the Stony River (Hangatahua), which is also protected for its cultural, historic and scenic values. Many of the plants found here have special adaptations to the acidic soils and very low temperatures.
The rare plant, Lepidium Cook’s scurvy grass, named for Captain James Cook’s habit of feeding it to his crew to ward off scurvy is still found on Ngā Motu / Sugar Loaf Islands
Although most of the park is free of introduced plants, several potential weed problems exist.
Wild ginger was a major problem in the park prior to a concentrated removal effort in the early 1990s, and surveillance continues in case of any major re-establishment. Asparagus scandens has also become a major problem in regenerating forests of the Kaitake Range fringe. Old man’s beard and hawkweed are also potential invaders.
Taranaki Mounga will control any weed infestations and protect against reinvasion so weed pests will no longer threaten the integrity of the lowland forest of the Kaitake Range, bluffs and stream banks.
Weeds will also be controlled regularly on the islands. But hundreds of starlings will continue to bring seeds to the islands, so boxthorn eradication will not be possible.