The Truth About 'Endless Summer' Hydrangea

You either love the fact that you can enjoy hydrangea blooms in your garden for the first time, or hate that this vaunted plant never lived up to its hype.

Photo: Steve Bender

You're looking at a bloom on my 'Endless Summer' hydrangea. It opened up just this week. This marks the first time any of my three 'Endless Summer' hydrangeas have ever produced a bloom later than June. Not exactly what I was told to expect.

You remember the hype about 'Endless Summer,' don't you? Here was a hydrangea that bloomed all summer long on both old and new growth. That "old and new" factor made a big difference. It meant that even if severe winter cold killed the plant (and its dormant flower buds) to the ground, it could still grow the next year and produce flowers. So Northerners so jealous of these gorgeous blue blossoms could finally enjoy the beauty that we Southerners know every June.

Does 'Endless Summer' Perform?

By and large, Northerners loved it. I scoured blogs and posts from gardeners all across the Upper Midwest and even Rocky Mountain states and many were wildly enthusiastic. They weren't getting repeat blooms, mind you. They were thrilled at just seeing blooms at all.

Down South, the reviews were less positive. Most people I talked to had the pretty same experience as I. 'Endless Summer' bloomed beautifully on both old and new wood until the end of June. Then when it got hot and dry, the way it most always does down here, the plant entered suspended animation and never produced another blossom.

Origins of 'Endless Summer' Hydrangea

How could this be? Well, you have to know something about the history of the plant. 'Endless Summer' was developed by Minnesota's Bailey Nurseries in collaboration with renowned woody plant guru, Michael Dirr. Walking through Bailey's planting fields, Mike noticed an unusual specimen of Hydrangea macrophylla that bloomed not only on old growth, as most do, but on new growth too. And so 'Endless Summer' (the best marketing name for a plant ever bestowed) came to be. Bailey was just as shrewd about the pots for 'Endless Summer.' They wouldn't be ugly black, like 99% of nursery pots are. No, they would be bright blue, the same color as the flowers. As soon as the first 'Endless Summer' plants arrived, they literally flew out of garden centers all over the country.

Now Mike and Bailey are smart people. I don't think they'd put their names behind something that wouldn't produce as advertised. So what exactly went wrong?

Why 'Endless Summer' Stops Blooming

Well, let's pretend you're an 'Endless Summer' hydrangea growing in a pretty blue pot at Bailey Nurseries. Life is good. Every day, you get just the right amount of water and fertilizer to keep you in optimal condition. So you grow all through the summer, repeatedly producing new flowers.

Now you get planted in my yard in Alabama. Spring is nice, no freezing weather to nip you in the bud (what a great pun), and rainfall is plentiful. So you bloom like crazy from late May through June.

Then something awful happens. July arrives. It gets hot. Because you have lots of big leaves, you transpire a lot of moisture. You are always thirsty. But the mean, old Grump won't water you every day. Why, sometimes when he gets home from work, you're already wilting! Does he notice? No. He goes into the house and pops open a beer. Oh, very nice. Glad someone's getting a drink!

You decide to get even. After two weeks of hot, dry weather, you decide to hibernate. Oh, you'll keep your pretty green leaves all summer. But no matter what the Grump does from then on, you won't bloom again. Nosiree. You've shut down for the summer.

Best Conditions for an 'Endless Summer' Bloom

So why did mine repeat bloom for the first time this summer? Credit our wacky weather. Instead of our usual summer drought, we've had steady rain all July and August. Plus, this has been the coolest summer in Alabama I can remember. Last evening, out on our deck, it was 72 degrees! The high for the day was 78. That's at least 10-12 degrees below normal. So 'Endless Summer' didn't go dormant. Thinking it was growing in Martha's garden on Long Island, it finally produced a second round of blooms. Yippee!

So do you need global cooling to get repeat blooms on 'Endless Summer?' Not necessarily. Try planting it in a container. People customarily water and feed plants in containers much more often than those in the ground. Under these conditions, 'Endless Summer' should think it's right back at Bailey Nurseries in Minnesota and bloom throughout the summer.

One final note: 'Endless Summer' may not be the panacea Northerners had been hoping for after all. In Cold Climate Gardening, blogger Kathy Purdy in upstate New York reports a rather dismal performance due to late spring frosts that damage leaves and buds and cool summer temps that inhibit flower production. Oh well. Guess she'll have to settle for those blue plastic hydrangea blooms from Wal-Mart after all.

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