New England blazing star is a 2½-foot-tall plant with purple flowers that bloom from late August to October.

A member of the aster family, it is native to the Northeast and used to be widespread in Massachusetts, but is now listed as a Species of Special Concern under the Massachusetts Endangered Species Act.

“New England blazing star is rare and declining everywhere, but the losses in recent decades have been sharpest in northeastern Massachusetts,’’ said Bryan Windmiller, director of field conservation at Zoo New England.

Windmiller and colleagues at Zoo New England, the Arnold Arboretum, MassWildlife, and elsewhere began working on a project in 2017 to reintroduce the rare wildflower to locations in Middlesex County.

There were three main reasons behind the project, Windmiller said.

One was geographical. The plant had historically been found inside the Route 495 area, but in Middlesex and Essex counties it had largely been wiped out in the wild. Also, reintroduction sites, such as Lexington and Carlisle, were close by.

In addition, the species is attractive to native pollinators such as bees, wasps, moths, and butterflies.

“New England blazing stars produce high-quality nectar, especially for monarch butterflies tanking up before they migrate to Mexico for the winter,’’ Windmiller said.

Third, they are hardy plants that are easy to work with.

“They’re also really pretty flowers, very attractive,’’ Windmiller added.

Windmiller said a variety of factors have had a negative impact on New England blazing star populations. Buildings now occupy much of the dry, sandy upland habitat where blazing stars like to grow. An increase in forested habitat over the last several decades has resulted in the loss of open areas where blazing stars tend to be found. And invasive plant species — such as Asiatic bittersweet, multiflora rose, introduced honeysuckles, and glossy buckthorn — shade out blazing stars.

Increasing deer and rabbit populations also take their toll. Blazing stars have vertical stalks for flowering, and rabbits love to eat them, Windmiller said. Three-foot-high plastic fencing is used to keep rabbits out of reintroduction sites.

“The best populations in Massachusetts are on the Cape and the Islands, where sandy, nutrient-poor soils make it hard for other plants to grow,’’ Windmiller said.

While seeds for the blazing star reintroduction project originally came from populations in Boxford and Maine, Windmiller said he and his colleagues now collect the wind-dispersed seeds from reintroduction sites in Lexington and Carlisle.

After sprouting in a greenhouse at Eastern Connecticut State University, the seedlings are transferred to Windmiller and planted with mulch outdoors, where they are kept through their first winter in Windmiller’s and other peoples’ yards. Some plants also are grown at the Arnold Arboretum in Jamaica Plain.

Brendan Keegan, a horticulturalist at the Arboretum, said that last year the Arboretum overwintered about 200 specimens of New England blazing star that were originally collected by Windmiller. This spring a small population was introduced back into the Arboretum.

“This is significant for us, as the last known sighting of this species [in Suffolk County] was a 1933 specimen seen in our landscape,’’ said Keegan. “It’s great working with Bryan and his crew to repopulate our landscape with an uncommon native species using source populations from rural areas. We planted around 150 or so in our collections and the remainder are going to Bryan and his group to replant elsewhere in the state. We hope that this will be an ongoing collaboration of plant conservation and introduction.’’

Windmiller said the blazing stars are planted at reintroduction sites in September of their second year, and usually begin flowering by the third year. The main reintroduction sites are located in Lexington, Carlisle, and the Arnold Arboretum, with display patches located at Zoo New England’s Franklin Park location in Boston, the Fenway Victory Gardens in Boston, and Heywood Meadow in Concord. There’s also a new reintroduction site this year in Dunstable.

New England blazing stars are perennials, and can live six or seven years, Windmiller explained. They have a bulb-like underground structure called a corm, which allows them to survive the winter and sprout the following spring.

“All the rain we’ve had this summer has made it easier for new blazing star seedlings,’’ Windmiller said.

Windmiller said they plant new batches of blazing stars later in summer but by September to avoid heat and drought stress before winter. They plant 100 to 250 blazing stars per year, and have planted 700 since 2017.

Planting state-protected species, such as New England blazing star, is carefully regulated and requires permission from MassWildlife, Windmiller explained. But he recommends people plant other native wildflowers, such as purple Joe Pye weed, wild lupine, and New England aster, in their yards.

“Plant more native plants wherever you can because native plants support a higher diversity of insects, which in turn helps animals that eat insects, like songbirds, reptiles, and amphibians.’’

Don Lyman is a biologist, freelance science journalist, and hospital pharmacist who lives north of Boston. Send your questions about nature and wildlife in the suburbs to donlymannature@gmail