Spring has definitely sprung here in the Bay Area, and birds, bees and beasts alike are all atwitter over the booming odors and blooming colors.

In my yard, the nasturtiums have started their annual stealth campaign to overtake the vegetable beds, while the stubborn dandelions that I’ve pulled up a dozen times are again sprouting from cracks in the concrete path. (God bless the grass…)

Across the street, the wood sorrel that passes as my neighbor’s front lawn has exploded in a blanket of yellow as it does every year until he mows it down, concerned that his yard will attract a blight complaint for being unkempt. The fragrant fennel bush that grows shoulder-high alongside the vacant lot is going nuts this year too, and on walks around the block my dogs are clearly celebrating its return.

These familiar plants are a ubiquitous part of the landscape, so we usually overlook them as weeds, or more kindly call them “volunteers,” but there is more to these hardy urban perennials than meets the eye.

When I first got my house, nasturtiums (Tropaeolum majus) had gone feral and literally covered everything in the backyard. The progeny of those original plants are still thriving sixteen years later, although I have greatly restricted their territory. Also known as Indian cress or monk’s cress, nasturtium originated in the Andes and has since become naturalized in countries around the world, clearly one of Darwin’s favored children.

Besides creating a sprawling riot of color, nasturtiums are edible and are a terrific way to dress up a salad. The round leaves add wonderful variety to a greens mix, and the flowers themselves are surprisingly peppery, quite a bit like a radish. Make sure to inspect and/or rinse flowers before eating them, though, or an ant or two might contribute some extra protein!

When I’m out picking nasturtiums, I always eye the determined dandelions (Taraxacum officinale) to see if there are any young leaves that I can pinch from them as well. The best time to pick dandelion leaves is when they are small and light colored, generally before there is a yellow flower on the plant and certainly before there is a puffball to make a wish on.

Once dandelions start to mature, the leaves get thicker, more bitter and a little prickly. Young leaves are a great addition to a salad mix, and they are also fantastic sautéed with onions and garlic or mixed in with whatever cooked greens you are making.

If I want to fill out my salad bowl even more, I head across the street and poach a couple handfuls of wood sorrel from my neighbor’s “lawn.” Also known as Bermuda buttercup, sourgrass or soursop, Oxalis pes-capraehas a distinct tangy flavor that is sort of lemony. It’s great in salads, and the leaves, stems and flowers are all edible. You shouldn’t eat too much raw sorrel because it contains oxalic acid that can be hard on some folks’ kidneys, but adding it raw to salads now and then is fine, and cooking it eliminates the issue entirely.

If my salad still needs a little extra something, I take the dogs for a walk and go visit their favorite fennel bush (Foeniculum vulgare) to snip some feathery new growth from the top of the plant. And that brings us to some rules of thumb for gathering greens or flowers of any kind from urban areas:

• * Avoid roadsides where plants are contaminated by vehicle exhaust.
• * Be mindful of where animals relieve themselves.
• * Don’t pick in an area that could possibly have been treated with weedkillers.
• * Don’t eat anything you can’t identify with 100 percent certainty – a toxic plant can be as dangerous as a toxic mushroom. Stick to what you know.

With everything around us growing and blooming right now, it’s a great time to create your very own Spring mix. And who knows, the neighbors might even thank you for helping out with their weeding.