You switched to your trenchcoat a month ago. Your striped T-shirt is back in regular rotation.

And yet, spring still refuses to show its sunny face. It’s time to get out the big guns — you’re going to need to jump on this wicker trend.

“Wicker is summer and warm weather,” says designer Amanda Lindroth. “It’s just a staple of all porches and sunrooms.”

Sure, wicker is also a big part of that neo-hippie trend people are craving around the house these days.

It has a certain slouchy glamour.

But it’s also an undeniable marker of warm weather, evidenced by the fact that every spring, there it is again.

This year, it’s surfing a bigger trend wave than ever.

“It’s having such a resurgence right this minute,” says Lindroth, who authored a book late last year, “Island Hopping,” featuring homes she designed, practically dripping in wicker.

She collects wicker pieces, and she has launched a product line with a whole lot of wicker woven in.

Why the fascination? Maybe because she grew up in Florida, where you’d never think of resting your bathing-suited behind on a seat that wasn’t wicker.

But wicker “is not just for tropical climates,” she says. And, assuming you’re ready for a little bit of summer in your place, here are Lindroth’s rules for doing wicker right.

Forget grandma’s condo. Wicker, Lindroth admits, “kind of had a slippery slope for a while in Florida, where every town had a whole store full of bad wicker furniture.” This might have been the era in which a certain Florida condo you visited was decorated. “We’re talking full five-piece matching sets, right down to matching wicker end tables and dressers,” says Lindroth. “There was just too much of it. Everybody had to take a breather from bad wicker for a while.” This is not the wicker you’re looking for — the key thing, as with most decorating, is to steer away from a matched set of most anything, and instead buy the one eye-catching piece that you love.

Yes, you can leave it outside. This is the age-old question about wicker patio furniture — can it really stand up to porch or patio use? Lindroth says yes, providing you are willing to lower your standards and wield a can of spray paint. “You generally buy wicker in its natural color, and if you leave it out on the porch too long, it goes a little funny; it gets ratty. So everybody just gives in and takes it out to the garage and sprays it with a coat of blue paint or whatever color you choose. I like really dark colors, like black.” If you’re not ready to paint, just embrace the wear; Lindroth avoids buying the plastic stuff. “It just makes me sad.” Besides, “having been decorating on islands for the last 30 years,” says Lindroth, “I can tell you that a broken-down piece of wicker is a treasure.”

You will want to bring it inside. “I have woven furniture in almost every room I design,” says Lindroth, who knows that adding textural wicker or rattan to the mix gives a room a touch of nature and “the sense that something is handmade. I always want my interiors to look handmade.” Wicker has a lot of historical heft — it’s an ancient form (King Tut had wicker furniture) that brings an imperfect quality to your mix, even if you just add one wicker chair to the living room. And some baskets. And there was that rattan-framed mirror you spotted ...

You should check the thrift store. Luckily, wicker is one of the easiest finds to score in thrift and vintage stores, so be sure to shop around. Lindroth’s Palm Beach apartment was featured in House Beautiful, with four pedigreed wicker chairs that she snagged from a local thrift store — she didn’t even recover the cushions. “Those were very expensive chairs,” she says, “and I would never have had them otherwise.” Though she shops high-end wicker pieces for clients, good finds are everywhere when it comes to wicker, she says. “I have used the Ikea Agen chair (which retails for $80) probably 1,000 times in my career.” In fact, she has them in her home right now.

cdampier@chicagotribune.com

Twitter @csdampier