Hydrangeas are a great plant for the Maine climate. They can bloom as early as June, and maintain their beauty throughout the growing season and even into winter.

Skillins Greenhouses — with shops in Falmouth, Cumberland and Brunswick — is offering a class on hydrangeas at each location at 10 a.m. Sept. 15. In announcing the class, nursery officials asked, “Should the hydrangea be the official flower of Skillins Country?”

Just possibly. This is a relatively new phenomenon, though. Until about the start of the 21st century, hydrangeas were an old-fashioned shrub that people would put in the garden and love for their huge flowers, but not get overly excited about. We had an “Annabelle” arborescens hydrangea in our backyard, and we would see the PeeGee (paniculata grandiflora) and Nikko Blue hydrangeas in other people’s yards.

The “Endless Summer” hydrangea changed that, said Tim Bate, nursery manager at Skillins in Falmouth, who will be teaching the hydrangea course there. 

Michael Dirr, the premier woody plant specialist in the United States, discovered the plant in 1998 at Bailey’s Nursery in Minnesota. It was a macrophylla hydrangea that blooms on new wood as well as old, and just about guarantees blooms each year even in Maine’s tough climate.

“It does seem that every year, someone comes out with a new form of hydrangea,” Bate said. “There are so many great ones that do very well here in Maine.”

They are a workhorse in the garden, he says.

“They can’t be matched for late-season color and as a plant that blooms for such a long time,” he said. “Many shrubs come into bloom for a week or two, and then they are done.”

Arborescens hydrangeas are native to the United States, although it is difficult to find the species version. “Annabelle” is the most common variety, and has been around the longest. In the past few years, two pink varieties have been introduced, “Invincibelle Spirit” and “Bella Anna.” 

Bate said the new colors on those plants are great, which make them popular, but they do have a tendency to flop — one of the major complaints about hydrangeas.

“Incrediball” is an arborescens that has bigger heads and stronger stems than Annabelle, and is supposed to do less flopping.

Bate said that at Coastal Maine Botanical Gardens in Boothbay, they have had some success keeping their arborescens hydrangeas from flopping by bunching them together. The ones on the edge may still bow down to the ground, but the ones in the middle remain upright.

If you are concerned about hydrangeas flopping, Bate has some advice. First, consider lacecap hydrangeas, which have flowers that are not as heavy as the mop-heads, and go with paniculata varieties.

” ‘Pinky Winky’ is a nice new variety that is known for the upright habit of its flower heads,” Bate said. It has two-tone flowers of cream and red, and can grow to 8 feet.

Bate said “Limelight” is very strong, with smaller flower heads of light green. “Quickfire,” in addition to being a sturdy and upright shrub, is one of the first hydrangeas to bloom in the garden, and keeps its flowers all winter long, he said.

I read somewhere that you can leave last year’s stems on the hydrangea plants to keep this year’s blossoms from flopping, and I asked Bate about it. He had not heard that, but said it would be worth trying.

There are several macrophylla hydrangeas in the “Endless Summer” series that have been introduced in recent years and have some advantages.

“I do like ‘Blushing Bride’ for those who are looking for lighter-color blooms on new wood and old wood,” Bates said. “It starts out a light-green color and then turns blue or pink, depending on whether the soil is acid or alkaline.

“I am also very fond of ‘Twist ‘n Shout’ because of the lacecap flower. It has a very strong, deep-blue color with red stems that are great, and I like how the foliage adds to the fall landscape.”

Bate mentioned “Blushing Bride,” but a lot of the macrophylla hydrangeas, including “Endless Summer,” can be either pink or blue depending on the acidity of the soil. The more acidic the soil, the deeper blue the flowers will be.

Several fertilizer products are used to let people pick the color of their blooms, but you also can add lime if you want pink or sulphur if you want blue. Or you can just plant them and see what you get.

LOCAVORE DAY at the Atwell garden went well. The Cumberland County Extension made the right choice to hold the event on Saturday despite the forecast that the better day was going to be Sunday. Rule No. 1: Never cancel anything based on a forecast.

We forgot to keep count of the visitors, but Nancy and I agree it was close to 75 — which surprised us, because fewer than 50 tickets had been sold as of the Tuesday before the event.

People seemed equally interested in vegetables and flowers. A Master Gardener specialist in worm composting was on site all day. People who came in the morning got to try some applesauce canned by Extension volunteers.

I hadn’t realized that because the Extension had listed root cellars as a topic, I was going to have to give the talk on that topic. Our root cellar is made out of our cellar bulkhead area, and I wish I had straightened up the cellar some. 

Although the garden was almost weed-free on Wednesday, the wet weather on Friday when I couldn’t weed allowed a lot of them to sprout, and I kept noticing weeds as I took people through the vegetable garden. We enjoyed meeting other gardeners and showing off our gardens, but we are definitely not going to be on another tour for another year or so. We need some rest.

Tom Atwell has been writing the Maine Gardener column since 2004. He is a freelance writer who gardens in Cape Elizabeth and can be contacted at 767-2297 or at:

tomatwell@me.com