Ambergate Gardens (www.ambergategardens.com) is ending its run.

For 28 years, the plant-only nursery in Chaska has been a destination for gardeners seeking unusual hardy perennials.

But owners Mike and Jean Heger have decided it's time to retire from retail. They announced the news "with mixed emotions" in a recent letter to customers, saying they were "ready to have some free time during the growing season."

"It's bad for our customers, good for us," said Mike in a phone interview. "We're not going to retire from horticulture, but we're ready to put a little different spin on it." He hopes to do more teaching, speaking and writing. "If I can find a publisher, maybe I'll write another book." (His "Growing Perennials in Cold Climates" was published in 1998 and updated in 2011.)

"We want to keep the Ambergate name, but as more of a consulting business."

The Hegers have signed a purchase agreement with Mattamy Homes to sell their 42-acre site, which is slated to become a housing development. "We bought this piece of property with this in mind," he said.

That leaves the Hegers with a whole lot of plants to sell before Oct. 13, when they expect to close Ambergate's doors for good. To that end, Ambergate is holding its "one and only sale" with 25 percent off all stock. "We'll start liquidating next week (on Sept. 10) and sell til it's gone," he said. (Customers who received the Hegers' letter can bring it in for an additional 10 percent off.) "We want our active long-term customers to get the greatest discount."

The inventory includes about 30,000 plants representing 1,000-plus varieties, propagated on site. "We have natives, exotics, sun to shade plants and traditional perennials," he said.

That includes many unusual, hard-to-find perennial species. "There are a lot of really good perennials that don't get into the mainstream," he said, such as Lemon Queen, a sunflower with prolific blooms in a "rich, clear lemon yellow," and unusual natives like wild quinine.

"We do some things nobody else does," he said. "There's definitely going to be a void here. Hopefully, someone else will step in."