If you love a garden, or just the wild corners of one, here's a reason to set an alarm this weekend and look down.

On the first hard freezes of fall, a few native plants push out thin, curling ribbons of ice from their stems. They're called frost flowers. They look like spun sugar, or a curl of lace, and they're usually gone by midmorning.

How frost flowers form

The recipe is short: warm ground, then a sudden hard freeze. The roots are still active, so they keep pulling water up the stem. When the freeze cracks the stem's surface, that water slips out and freezes the moment it meets the cold air. More water behind it pushes the ice outward into ribbons.

The Missouri Department of Conservation says scientists still can't explain why only a few species do it. People have been puzzling over it for nearly 200 years. A naturalist wrote about it in an 1828 journal, and University of Texas at Austin researcher Bob Harms calls the ice "crystallofolia," or "ice leaf."

(MORE: Should you water your garden before a freeze? Here's what the pros say)

Where to look for frost flowers

Go at dawn and check the base of dead-looking stems along woodland edges and roadsides. Your best bets:

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• White crownbeard (frostweed), native across much of the central and southern eastern U.S.
• Dittany (stone mint), a fragrant little perennial with purple-lavender blooms that bees love, and leaves that turn red-purple in fall. You may already have some in your garden.
• Camphorweed, a rarer find, but a known producer.
• Yellow ironweed, which is sometimes reported, though the evidence is thinner.

Your best chances are the Ozarks, the Ohio and Tennessee valleys and the southern Appalachian edges.

Another icy find: needle ice

Keep an eye out for needle ice too. These are fine threads of ice that push straight up out of soggy ground, and they snap and crackle under your boots.

(MORE: Weather Words: needle ice)

Don't count on them (but do look)

As with any good treasure hunt, there's no guarantee. It takes the right plant, moist soil and a sharp freeze. But the chance is good, and it's a lovely, free excuse to get the kids outside with a mug of cocoa. Look gently, because these are delicate.

Show us your frost flowers!

Did you find one? Don't keep it to yourself. Snap a photo before the sun melts it, and post it in the comments below. Tell us where you found it and which plant it was growing on. We'd love to see what's blooming at your feet, and we may feature our favorites.

weather.com Content Development Manager Joy Kigin chases stories where weather, science and culture meet everyday life, the kind that spark conversations and, now and then, a smile.