“It’s up,” she said last week.

She knows it’s the bane of farmers, but it is one of her favorites. She describes its taste as “sweet and delectable.”

Timing is critical; if you wait too long to pick it, it’s bitter, and that happens in just two to three weeks. Harder advises, “Just pick the tender inner leaves and stop when they have buds.”

Once it's picked, you can wash and then steam the leaves and stems in a small amount of water until they are tender. “The greens cook quickly and turn a dark green,” she says. She enjoys them with butter and a little salt and pepper.

“Anything else would overwhelm them,” she said. “They’re delicate.”

Harder learned about edible wild plants from her grandmother, an amateur botanist, and she has, in turn, passed the knowledge on to her son.

“My grandmother brought me up during the war years,” said Harder, as her father served in the Navy and her mother volunteered at a hospital.

“I wish I knew half of what she did. I knew it as a child. She taught me the Latin names and everything.”

Her grandmother, Hazel, was a Holden — a family rooted in Oak Hill, Maine. “They grew and made everything they needed themselves,” said Harder.

The members of the large family would spend the long winter evenings reading, by the light of an oil lamp, the Encyclopedia Britannica out loud to each other.

“I come from a long line of nerds and geeks,” said Harder.

Hazel’s father, Willis Holden, born in the mid-1800s, was a cactus collector and beekeeper. He moved to Acton, Massachusetts where he had an apple orchard and where he raised cows, pigs, and chickens. He had two children, Una and Hazel; their mother died of tuberculosis when Hazel was 12 and Una became her father’s steady helper.

The rocks on his land were so stubborn, Willis Holden used dynamite to blast them loose. “He taught Una to set dynamite,” said Harder.

After her mother died, Hazel was sent to California to live with an uncle. She lived in Belvedere, an island off the coast of California. In 1906, she watched, from the island, the earthquake and fire that ravaged San Francisco, and wrote about it in a letter, which was published.

When she returned to the East, Hazel lived with another relative whose wife was a Juilliard musician. Hazel was sent to Juilliard in New York City where she played the violin.

“She said she was a mediocre violinist; it was not her thing. Her talent was botany. She hung out at the Museum of Natural History in her teens,” said Harder.

When Hazel grew up, she did research on nutrients in plants, corresponding with a professor at Cornell University. “They wrote back and forth all the time,” said Harder. She also corresponded with Mr. Chubb at the Museum of Natural History.

She married Breck Aspinwall and became a mother and later a grandmother, instilling in her progeny a love of wild edibles, which Harder is eager to share.

Harder starts with some practical advice for the uninitiated. “Be sure to identify the plant and don’t eat any that have been sprayed with weed killer or pesticide. No roadside greens either,” she stresses.

Harder cites Euell Gibbons’s “Stalking the Wild Asparagus” as a useful reference. The cover of his popular 1962 book says this: “A delightful book on the recognition, gathering, preparation and use of the natural health foods that grow wild all about us. The lore here can turn every field, forest, swamp, vacant lot and roadside into a health-food market with free merchandise.”

“There aren’t many resources,” Harder says of books on the subject. “The Internet is a tremendous source.”

Dandelion greens are among the most familiar of the natural edibles, even sold in grocery stores. “Nice fat broad dandelion leaves come early though they’re not my favorite wild greens,” says Harder. “European settlers introduced them as a salad greed and they’ve been a plague to most fans of uniform green lawns composed of grass blades.”

With all of the wild edibles, Harder says, “You want the newest, freshest, youngest. Old ones get bitter.”

How does she prepare them? “I do what my grandmother did — cook them in a liberal amount of water and drain them.”

She concludes about dandelions, “Personally, I love the flowers and the plant is very drought resistant, so I just enjoy the blooms then mow them later.”

Later in the spring, milkweed emerges.

“The greens are really a delicious treat,” says Harder. “I’m not the only one to think they are better than asparagus.”

She advises picking only the tender top rosettes so the plant branches out to make leaves for the monarch butterfly caterpillars to feed on. She also advises leaving some of the plants untouched.

In the last decade, monarchs have suffered a ten-fold drop in population, decimating the numbers that make their famous annual migrations, and leading some scientists to fear extinction. There is a movement encouraging people to plant milkweed to help sustain the monarch population.

“I don’t understand why more people don’t grow it as a garden plant,” Harder said of milkweed. “It has a beautiful flower.”

Once the monarch butterfly emerges from its chrysalis, it uses the nectar of the milkweed flower.

“I saw two monarchs last year and I’m hoping some survived for this year,” Harder said.

Harder’s favorite wild edible is lamb’s quarters, also known as pigweed, goosefoot, or Chemopodium album.

“It comes up in cracks in sidewalks in the city,” said Harder. “It’s absolutely ubiquitous. People rip it out of the garden as fast as they can.”

But Harder takes a different approach. Her idea is to eat it before she weeds it.

“I do a pick and pull,” she said. “I don’t weed them out before I’ve harvested the tender tops for dinner or freezing. Sort of like having your cake and eating it too.”

She picks the six- or eight-leaf rosettes and then steams or boils them briefly. The leaves shrink down as they are cooked and turn dark green. The young leaves and smaller stems can be eaten raw in salads. “But I don’t love it so much raw,” said Harder.

Sometimes she prepares an Italian-style dish where she steams and drains the lamb’s quarters. In another pan, she sautés onion and garlic; when it is caramelized, she tosses that in the cooked greens, adds salt and pepper, and simmers for five minutes. She adds crumbled feta cheese and chopped fresh tomatoes before tossing.

Harder points out that lamb’s quarters is extensively cultivated as a food crop in northern India. “It got here from India, Pakistan, southeast Asia; they brought it over and it went berserk,” she said.

“It can be used to make a curried greens with chick peas dish that I really enjoy. This country treats it as a weed,” she laments.

Harder also notes that Michael Pollan in his book, “In Defense of Food,” calls lamb’s quarters and purslane “two of the most nutritious plants in the world.”

“I confirmed what my grandmother told me — lamb’s quarters has the most vitamins and minerals you can get in a green thing.”

Why is it her favorite? “It’s delicious,” says Harder. “Its taste is close to spinach but I like it better than spinach.”

Harder also freezes “enormous quantities” of lamb’s quarters or pigweed. “You just blanche it — drop it in boiling water — cool it, and freeze it, It’s easy and way better than corn.”

It keeps its flavor and texture when frozen, she says, and she enjoys eating it all winter.

“I’ve been nurturing a giant pigweed that will be taller than me in August,” said Harder. “I let it seed — oh, does it drop seeds!”

The next generation of her family — Harder’s grandchildren are aged 5 and 9 — are carrying on the tradition.

“My grandkids eat pigweed and love it,” she said.