Jeremy Siegel: This is GBH’s Morning Edition. We’ve had a good patch of weather with blossoms everywhere you turn, and this is causing some issues for people who suffer from seasonal allergies. Here with me to talk more about that and answer your questions about the weather and the garden is GBH meteorologist and gardening expert Dave Epstein. Good morning Dave.

Dave Epstein: Good morning. Good to be here.

Siegel: So let’s start with allergies. Liz in Arlington wrote to us saying, I’d like to know when the pollen season from pine trees begins and ends in Boston, and what affects the intensity and the amount of pollen?

Epstein: Yeah. So pine pollen is the yellow stuff — yellow, yellowish green — that we start to see this time of the year. And it continues up until about mid-June. So another few weeks. It’s actually not an allergen for nearly everybody. There’s probably some exceptions, so I don’t like to say everybody. But most people are not allergic to pine pollen. So if your allergies are bothering you it’s not the pine pollen. It’s dusty. It’s messy. It gets on things. If you leave your windows open, it gets on the furniture. But that’s really the only impact of it.

Siegel: Let’s talk about the other allergies, because lots of people are struggling right now. What is blooming, what’s causing that and is it getting worse?

Epstein: Yeah. So pollen goes through a cycle. Just like we see, early on, you get crocuses and then we go to daffodils and then we go to tulips. Pollen is the same thing. You get the initial tree pollen. So we get the early maples. We get the Acer rubrum, which are the red maples. That’s one of the first ones to come out. And now we’re on to the oak pollens which are beginning to wane. And we’ll get the pine pollen, which again isn’t an allergen, and we get grass pollen, and then we start getting things like the ragweed later on in the summer, as we head into August and September, you get those pollens. 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.

Siegel: Let’s get to some other listener questions outside of allergies. And a reminder for people listening: If you have one, you can text them to us at 617-300-2008. We got a text saying 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. Is that right? And is there anything they can do?

Epstein: Yeah, that’s probably unlikely. Again, I can’t say 100%, but there’s probably not so much ground toxin that your flowers are blooming. The plants’ fine. So a lot of people with hydrangeas, a couple of things: One is 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. The other thing is is that 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. 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. So you don’t want to prune. Also, maybe just some fertilizer, some bloom stuff to help the hydrangeas. Or if you really don’t like it, rip it out and get a different variety and start over.

Siegel: We have a question from Catherine that is about food and crops, buying at the store. She says: Each year when I buy 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 do I keep them together? Why do they come in sets of three? Any idea?

Epstein: Yeah. So when you plant cucumbers, zucchini and some of the other cucurbits, they do come in little things of three. I actually plant them in threes. And the reason being is that one tends to take over. 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. You don’t have to separate them. You can put them in in the threes. But you want to, 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.

Siegel: Before we let you go, Dave, wanted to ask what’s going on in your garden this week.

Epstein: Well, I’m going to put the tomatoes in probably today or tomorrow morning. They are not in yet. They’ve been sitting outside for the past week or so getting them hardened off. I wanted to wait until I got by that heat. I put down a red plastic mulch on the area where the tomatoes are, I’ll poke holes in that the tomatoes will go in and they’ll be in for the season. I’m also going to do peppers and eggplants this week.

Siegel: What’s the reasoning behind the red plastic mulch?

Epstein: There’s some research, actually. It’s actually real research that shows that the light reflected from the red plastic mulch does help yield. Yeah. So you can Google the red plastic tomato mulch and you just have to remember to poke holes in it. And I try to use it for 2 or 3 years in a row, so I’m not kind of wasting it.

Siegel: That is GBH meteorologist and gardening expert Dave Epstein. Dave, thanks for your time.

Epstein: You’re welcome.

Siegel: You’re listening to GBH News.

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  thewakeup@wgbh.org, 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.