Maui’s rarest plant nearly vanished once — now one man is racing to save it again

A summit nursery fights to save it

High on the slopes of Haleakalā volcano on Maui, a small nursery sits near the 10,023-foot summit growing silversword seedlings in black plastic pots.

Park biologist Woody Mallinson runs the operation, sheltering young plants until they can handle the wild on their own. The park has planted about 500 to 1,000 seedlings each year since 2016.

Visitors can spot silverswords near the summit parking area, at Kalahaku Overlook, and along the Sliding Sands Trail into the crater.

This plant grows nowhere else on Earth

The Haleakalā silversword, known as ʻāhinahina (meaning “very gray” in Hawaiian), exists only on this one volcano.

It looks like a silvery, spiky ball of sword-shaped leaves covered in fine hairs that reflect sunlight, block wind, and pull moisture from passing clouds.

The plant can live anywhere from 15 to 90 years, but it flowers just once, shooting up a stalk as tall as 6 feet with up to 600 flower heads. After it scatters its seeds, it dies.

Because silverswords can’t pollinate themselves, they depend on native insects like yellow-faced bees to reproduce.

A California weed started it all

Here’s something wild: DNA analysis confirmed that the silversword evolved from a California tarweed seed that drifted across the Pacific Ocean millions of years ago.

That single ancestor gave rise to more than 30 plant species found only in Hawaii, a group scientists call the silversword alliance.

The Haleakalā silversword lives in a roughly 2,500-acre patch atop the volcano, a barren landscape of volcanic cinder cones.

Botanists have called this alliance one of the best examples of plant evolution through geographic isolation anywhere in the world.

Tourists and goats nearly wiped it out

In the early 1900s, visitors uprooted silverswords as souvenirs or rolled them downhill for fun. Feral goats ate the rest.

By 1935, researchers estimated the population had dropped to somewhere between 11,500 and 18,000 plants. The Maui Chamber of Commerce asked the federal government to step in.

The National Park Service fenced out the goats and educated visitors, and the population bounced back to tens of thousands by the early 1990s.

For decades, the recovery stood as one of Hawaii’s great conservation wins.

Drier weather triggers a second collapse

That success story didn’t last. Starting around 1990, silversword numbers began falling again, this time because of drier and warmer conditions on the mountain.

Research funded by the U.S. Geological Survey found the population has dropped about 60% since then. The U.S. Fish and Wildlife Service listed the plant as threatened under the Endangered Species Act in 1992.

The decline lined up with reduced summer rainfall at the high elevations where silverswords grow.

Clouds can’t reach the summit anymore

A weather pattern called the trade wind inversion is a big part of the problem. It traps clouds at lower elevations, leaving the silversword zone hot and dry.

When the inversion breaks, clouds and rain reach the high slopes and give the plants the moisture they need. Scientists have found those breaks happen less often now.

Climate projections suggest the drying trend could get worse in the coming decades, which means even less water for the silverswords.

An invasive ant threatens the pollinators

The Argentine ant, an invasive species first found in the park in 1967, preys on native insects that never evolved defenses against ants.

Native pollinators like yellow-faced bees are especially at risk as the ant spreads into higher elevations.

Researcher Paul Krushelnycky of the University of Hawaii has said the ant isn’t driving the silversword decline right now but could become a serious threat as it expands its range.

Fewer pollinators combined with drier conditions could make recovery even harder.

Scientists pinpoint the best planting spots

A three-year University of Hawaii study found that silverswords survive best when planted at higher elevations.

Plants placed at lower, wetter spots actually died at higher rates during dry spells because they built up less drought resistance. That finding surprised researchers and changed the park’s approach.

The park now models the best habitat zones based on climate data and targets those areas for planting, giving each seedling the best shot at survival.

Fourth graders plant silverswords at the summit

Local fourth graders visit Haleakalā to learn about conservation and plant silversword seedlings with their own hands. For many of the kids, it’s their first trip to the top of the mountain.

Their work shows up around the summit parking area and nearby slopes, where young silverswords shine against the dark volcanic ground.

The program connects a new generation with the cultural and natural importance of the ʻāhinahina, turning a classroom lesson into something they can see and touch.

Volunteers fill gaps the park can’t staff

The Friends of Haleakalā National Park, a volunteer group, helps with outplanting and runs monthly nursery work days. Volunteers clean pots, pull invasive weeds, and gather seeds.

The group also sponsors youth scholarships focused on natural resource stewardship. Their help matters more than usual right now.

High housing costs on Maui make it hard for the park to recruit staff, so volunteers pick up work that might otherwise go undone.

The park protects more endangered plants than any other

Haleakalā National Park has more endangered plant species than any other national park in the country. The nursery grows dozens of other at-risk native species, from rare mints to geraniums and lobeliads.

The silversword itself plays a key ecological role as a host for several insects found nowhere else.

Protecting these native plants also helps reduce harmful runoff and supports water quality for communities living downslope.

The silversword’s future depends on the climate

Scientists keep searching for areas in the park where conditions might help silverswords survive a drier future.

The nursery holds backup plants and seeds to preserve genetic diversity in case outplanted seedlings don’t make it.

Park crews also helicopter into remote backcountry to check fence lines and remove feral animals that threaten native species. The silversword survived human destruction once before.

Whether it can outlast a changing climate is the question no one can answer yet.

This article was created with AI assistance and human editing.

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