Megaherb Facts for Kids

A megaherb community on Campbell Island, one of the subantarctic islands of New Zealand. The yellow flowers are Bulbinella rossii (Ross Lily), and the pink flowers are Anisotome latifolia (Campbell Island Carrot).

Megaherbs are a special group of large herbaceous perennial wildflowers. They grow on the New Zealand Subantarctic Islands. These plants are known for their huge leaves and very big, often brightly colored flowers. They have grown this way to survive the tough weather on these islands.

In the 1800s, farm animals were brought to the islands. These animals ate many megaherbs, and the plants almost disappeared. But after the animals were removed in 1993, the megaherbs grew back quickly and strongly!

Where Megaherbs Grow and Their History
Types of Megaherb Species
Other Plants Growing Nearby
Threats and Recovery
Images for kids
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Where Megaherbs Grow and Their History

Megaherbs are found on several subantarctic islands in New Zealand. These include the Snares, the Auckland Islands, and the Campbell Island group. These plants developed their unique features because of the islands' climate and soil, and because there were no plant-eating animals there. The weather is usually wet, cold, and very windy. The soil is peaty, acidic, and not very rich in nutrients. Also, the islands are often cloudy, so they don't get much sunlight.

The name 'megaherb' was first used by James Clark Ross. He was on an expedition to Antarctica from 1839 to 1843. Joseph Dalton Hooker, a plant expert on the trip, wrote that megaherbs created a "floral display second to none outside the tropics." This means their flowers were incredibly beautiful, almost like those found in warmer places.

Even though megaherbs are smaller than plants in tropical areas, they are much bigger than other herbaceous plants on the subantarctic islands. Usually, the harsh weather and poor soil on these islands make plants grow small. But megaherbs are different!

Types of Megaherb Species

Most subantarctic megaherbs have a special flowering pattern. They bloom all at once, in huge numbers, about every three years. In the years in between, only a few plants will flower. It's not nearly as impressive as when they all bloom together.

One important megaherb is Bulbinella rossii, also called the Ross Lily. This plant grows in clumps and has long, thick, strap-like leaves. It can grow up to 60 cm (24 in) tall. Its bright yellow flowers grow on stems that can reach 90 cm (35 in) high. Its closest relatives are found in mainland New Zealand and South Africa.

Anisotome latifolia, known as the Campbell Island Carrot, has pink flowers. These flowers grow in huge clusters that can be up to 75 cm (30 in) wide. The stems holding these flowers can be as tall as 1.5 m (4.9 ft).

Pleurophyllum speciosum, the Campbell Island Daisy, looks like daisies from Africa and the Canary Islands. It forms a giant rosette, which is a circular arrangement of leaves. This rosette can be up to 1.2 m (3.9 ft) across. Its leaves are huge, wide, and pleated. The flowers are pinkish-purple to light lilac with dark red centers. They grow on stems up to 60 cm (24 in) tall.

Two other Pleurophyllum species are also megaherbs. They are Pleurophyllum hookeri and Pleurophyllum criniferum, also called giant button daisies. They can grow up to 90 cm (35 in) tall and have similar wide leaves. P. hookeri has crimson (deep red) flowers, while P. criniferum has flowers that are almost black. Sometimes, these different species can even create natural hybrid plants.

The Black-eyed Daisy, Damnamenia vernicosa, has white flowers that are 5 cm (2.0 in) wide. However, the plant itself only grows to about 10 cm (3.9 in) high.

Stilbocarpa polaris, or Macquarie Island Cabbage, is part of the Aralia family. It grows in clumps up to 90 cm (35 in) tall. It has ribbed, rhubarb-like leaves and lime green flower clusters. These clusters can be up to 60 cm (24 in) wide.

Other Plants Growing Nearby

Other plants grow alongside the megaherbs. These include hebes, different kinds of daisies, amber sedge, and three types of gentian. One is Gentianella cerina, the giant gentian. It grows to 15 cm (5.9 in) tall with flowers 2.5 cm (0.98 in) across. Its flowers can be white, pale pink, red, or purple. The other two gentian species are Gentianella antarctica and Gentianella concinna, both with pinkish-red flowers.

Threats and Recovery

The New Zealand subantarctic islands do not have people living on them permanently. Only scientific researchers stay at a weather station on Campbell Island. In the 1800s, animals like rabbits, pigs, sheep, goats, and cattle were brought to the islands. The idea was to provide food for sailors who might get shipwrecked.

However, these wild animal populations grew too large. They ate so many megaherbs that the plants were in serious danger. The New Zealand Department of Conservation started removing all these introduced animals in 1987. They finished this work by 1993. Just three years later, in 1996, plant experts were amazed. The megaherbs had grown back incredibly fast and spread widely!

It is against the law to collect megaherbs from the wild. Even megaherbs grown in botanical gardens, like in Invercargill in New Zealand's South Island, look weak and small compared to those in the wild. Megaherbs need the very specific weather and soil conditions of the subantarctic islands to grow well. They don't do well in what seems like easier conditions.