What’s that weed? 6 roadside plants you see on Long Island

One day last summer when I was exiting the Meadowbrook Parkway at M1E/Old Country Road, my daughter Justine pointed out a virtual field of periwinkle-blue flowers. “Those are beautiful!” she remarked while snapping a photo as I drove around the bend. “What are they, and can we plant them in our garden?”

She was right: They are beautiful. Chicory, a member of the dandelion family, certainly is eye-catching, especially when growing en masse. My father used to forage for it and use its bitter leaves in salads, as did Thomas Jefferson before him. And my mother, who grew up in northern Italy, remembers drinking a brew of its dried taproot as a wartime substitute for coffee.

But the reason we don’t grow it in our garden is because, although not considered invasive, chicory is still a weed. It’s all fun and games and blooms during the day, when flowers are bright and distract from the plant’s untidy habit. But come evening, flowers all but disappear, leaving behind a rather messy tangle of scraggly stems that look, well, weedy.

Chicory isn’t the only striking roadside plant on Long Island. Whether you’re driving along a highway or side street, you’re bound to spot a profusion of (sometimes) colorful weeds as well as wildflowers, trees and shrubs planted intentionally by the NY State Department of Transportation to serve as barriers, living snow fences and scenic vistas.

Here are five other plants you’re likely to encounter in your daily travels.

Forsythia

This early blooming shrub is among the first harbingers of spring, and I often advise gardeners to take its bright yellow flowers as a cue to apply annual pre-emergent crab grass control. Timing is everything, and forsythia is a good watchman in this regard. Planted either in a hedgerow or as a specimen, forsythia is a fast-growing shrub that can reach a height of 8 feet.

Daylilies

The botanical genus Hemerocallis is derived from a Greek phrase translated as “beautiful for a day.” Although plants put forth a succession of flowers that last several weeks, each blooms for just one day. There are several species of daylilies, but Hemerocallis fulva is the common orange flower lining many public roads. Native to Asia, it has been identified as invasive along the entire eastern U.S. coast, as it multiplies rapidly and forms dense patches that displace native plants.

Purple loosestrife

I’m especially disappointed this spiky, purple beauty is invasive because if it weren’t, I’d have an entire bed devoted to it, probably with some orange daylilies mixed in. Instead, I plant Liatris (gayfeather,) as it’s a suitable stand-in. Purple loosestrife is a wetland perennial whose seeds are readily dispersed by wind and wildlife. However, it’s still available for purchase at many retailers, and those who plant it sometimes remark that it doesn’t “take over the garden,” as one would expect an invasive plant would. And that’s the tricky part about some invasives: Their danger isn’t always immediately apparent.

Here’s what happens: Plants produce seeds, birds visit and eat them, then fly great distances and often to the shoreline before disseminating them in their excrement — and, yes, those seeds are still very viable. They settle in, germinate and sprout, and before you know it, there’s a stand of purple loosestrife competing with native plants for essential life resources, like sunlight, water and soil nutrients. And then there’s a domino-type effect on the food chain. Small wildlife that depended on the native plants are left without food, so they die off, and their predators are left hungry, as well. This can lead to an overgrowth of algae in the water, disrupt fish populations, upset crop pollination and even lead to the extinction of some wildlife or insect species. If you’re growing purple loosestrife or other invasive plants, please pull them up, bag them tightly in plastic and put them in the trash.

Wild parsnip

Wild parsnip looks harmless enough, with its lacy, dill-like leaves and flat yellow flower masses. But those whose bare skin contacts the plant while strolling on the roadside or hiking in a park have a different story to tell.

That story is of a painful, blistery burn called phytophotodermatitis, which happens when the plant’s sap touches skin and then is exposed to ordinary sunlight — even on a cloudy day. Painful blisters follow, and brown scars can last for years.

Queen Anne’s lace

Queen Anne’s lace is a biennial herb with lacy white flowers that bloom from May through October. Its long, carrot-like root lends it another common name by which it’s known: wild carrot. The cultivated garden carrot actually was derived from this plant, and Queen Anne’s long taproot, which develops in its second year, is just as edible, but its leaves are toxic. The plant’s tendency to grow and mature extremely quickly, often to the point of outcompeting native species, has earned it yet another common name: devil’s plague.