Longing for blooms on bigleaf hydrangeas?

Now that summer is over, are you among the many gardeners wondering what happened to Endless Summer?

The new bigleaf hydrangea called Endless Summer is supposed to bloom all summer on new wood. Unlike previous bigleaf hydrangeas, Endless Summer's season-long flower show shouldn't be spoiled by a winter cold snap killing the buds on year-old stems.

That should be good news for all of us who garden in the upper Midwest, where bigleaf hydrangeas have often failed to bloom. But when I wrote about the virtues of Endless Summer hydrangea, I heard from a lot of readers asking what went wrong.

Some mentioned seeing lovely flowers the first year but none this past summer. Some reported conflicting advice, ranging all the way from coddling Endless Summer with more food and water to stressing plants by withholding those essentials.

For the answer, I went to Bailey Nurseries, birthplace of Endless Summer. Spokeswoman Peggy Anne Montgomery said the company has been hearing similar reports this year, primarily from north-central states. She says there's no easy 1-2-3 answer, because "Mother Nature is more complicated than that."

Partly to blame is this year's odd weather that wreaked havoc on plants of all kinds, when unusually warm weather early in the season was followed by a frigid April plunge. Some bloom failures can also be traced to cultural problems, such as too little sunlight or too much nitrogen in the fertilizer.

"We know there's nothing inherently wrong with the variety," she says, "because we've been growing it successfully in the Twin Cities for over 20 years."

Montgomery says the people from Northscaping.com (a Canadian Web site specifically for northern gardeners) think the trouble is that most of us who garden in the north haven't had much experience growing bigleaf hydrangeas and don't know what to expect. To read the full story, filled with advice on successfully growing your own Endless Summer, go to www.Northscaping.com. Click on "Info Zone," then on "A Lifetime of Endless Summers." Here's the part I found most eye-opening:

All bigleaf hydrangeas are characteristically slow to get going and are likely to have limited flowering the first few years. The Endless Summer you bought in glorious bloom was likely forced into bloom ahead of its time under optimal indoor conditions and will require several years to get established before you can expect it to repeat this performance.

Other tips: Don't prune the first two or three years, except to remove dead flower heads in spring. Aim to keep the soil consistently moist, not soggy. Use a low-nitrogen, high-phosphorus fertilizer, such as one labeled 10-40-10.