Meteorologist Dave Epstein is our go-to person for pressing weather questions on everything from winter blizzards to summer droughts. He’s also a horticulturist, meaning he’s an expert in anything that grows leaves and flowers. GBH’s Morning Edition asked our audience for weather and gardening questions, and Epstein graciously answered them on the air.

Have a gardening or weather question for meteorologist Dave Epstein? Tweet him @GrowingWisdom, email us at, or text 617-300-2008.

I’d like to know when the pollen season from pine trees begins and ends in Boston. — Liz in Arlington

Pine pollen is the yellowish-greenish dust that coats our streets, cars and sidewalks from late May to mid-June.

Pollen, Epstein said, goes through seasonal cycles. Just like New Englanders can expect to see crocuses in bloom, then daffodils, then tulips, pollen is on a schedule, Epstein said: Red maples, oak pollens, pines, grasses.

“Then we start getting things like the ragweed later on in the summer, as we head into August and September, you get those pollens,” Epstein said. “But there’s no, necessarily, one pollen that’s bothering us during the course of spring and one more in the summer. There’s many types of pollens moving through the atmosphere, and it ebbs and flows with rainfall and wind and all of that.”

Not everyone is allergic to pollen.

“There’s probably some exceptions, so I don’t like to say everybody. But most people are not allergic to pine pollen,” he said.

But even when pine pollen is not an allergen, it can still be a nuisance.

“It’s dusty. It’s messy. It gets on things. If you leave your windows open, it gets on the furniture,” Epstein said.

We planted hydrangeas in our side yard three years ago and they’ve never bloomed. We live in Somerville, where the soil is full of questionable substances, so we assume the flowers are inhibited by ground toxins. But is there anything we can do?

It’s hard to say for certain, Epstein said, but it’s unlikely that the hydrangeas aren’t blooming because of soil contamination.

“There’s probably not so much ground toxin that your flowers are blooming,” he said. “The hydrangea itself has to be hardy. So sometimes people pick up hydrangeas at the grocery store and then plant them. And they’re actually a non hardy variety of hydrangea. So that can be the issue.”

Another possible culprit: Improper pruning.

“In the fall when the leaves fall off, you’re left with these sticks and they’re very ugly. And a lot of people cut those back,” Epstein said. “Those actually have the flower blossoms for the following year. So if you prune them and cut them back, you’ll never get flower blossoms because you keep cutting the flower blossoms off.”

Try foregoing the pruning and adding a bit of fertilizer to the ground, Epstein said. If that doesn’t work, remove the plants and plant a hardy variety.

Each year when I buy my zucchini and cucumber plants, they come in groups of three, and this confuses me. Do I separate the set of three that I bought, or keep them together? — Catherine

You can separate the plants, but you don’t have to, Epstein said.

“The reason being is that one tends to take over,” Epstein said. “Also, we get cucumber beetles and we get borers on some of the zucchini. So if you end up with three and a couple of them end up going, you still have one plant left.”

Epstein plants his in bunches, he said. But there is one important thing to keep in mind: You can plant hills of three plants, but remember to keep them at least three of four feet away from each other.

“If you’re separating the hills, those want to be far apart. So a group of three in one hill and then like three, four feet, and then your next little hill,” Epstein said.