5. Why Don’t My Hydrangeas Bloom? Part I

Sherlock Holmes Discusses Growth, Siting and Deer Damage in Part I

Ah, Holmes, this case of the missing bloomshas been challenging gardeners for years. If you can solve it . . .

Blooms from buds that have survived winter nips, spring frost, and deer damage

Elementary, my dear Watson. We must follow the clues. First, we must examine how the hydrangea grows. Next we must discover what the hydrangea needs to produce blooms.

It’s a fine day in late summer, Holmes. Shall we enter the garden?

Look here, Watson. Observe these buds. They are beginning to grow, tucked into the axils of this year’s leaves. They are tight little packages that will unwrap to produce new stems, new leaves, and, with any luck, new blooms next year.

New buds have already begun to form in leaf axils during summer

But that’s the rub, Holmes, the blooms – where are they?

It’s a matter of energy, Watson. Growing and packaging buds takes energy. Then the bud must survive the winter.

And, look here, it must even survive tasting by deer. Take a look at how the leaves on this stem have been lost to browsing.

Now look at the buds. Instead of waiting for next spring, they are opening now. There will be no blooms on that stem next year.

Look closely. After deer stripped the leaves, the topmost buds are responding by growing! If the plant has enough energy, new buds may grow lower down on the stem

Aha! Either the plant does not have enough energy to create a bud that will bloom, or a perfectly fine bud may be damaged before it can bloom.

Quite right, Watson. Now the question to ask is. . . . .

Yes, Holmes, I’m reading your mind. How do we control the deer?

(Chuckling) That is a true enigma, Watson. We can keep them away with conscientious spraying and regular applications of blood meal, but they’ll be back.

I understand that deer netting works sometimes, but small animals can get caught in it unless there’s space between it and the ground.

Interesting: Deer scalp the Hosta “Golden Tiara’but they do not touch this strong, well established hydrangea. Leaving blossoms on may limit damage as deer seem to prefer the leaves

And sometimes the deer crash right through it. In a word, Watson, sturdy, high fences, or roaming, barking dogs are the only way. . .

The hounds of Baskerville would come in handy, wouldn’t they.

I dare say, Watson. But my real question is this: Are blooms missing sometimes because hydrangeas do not like where they are planted?

What’s to like or not like, Holmes?

We can find out by looking at a world map, Watson, to see where hydrangeas grow well. Hydrangeas come from islands in Japan, where temperatures range from the 80’s in summer to the mid-30’s in winter.

Pretty comfortable, eh? Rainfall can average almost 2 inches a week. With all this moisture, hydrangeas can afford to grow big leaves.

Many of the serrata lacecaps come from similar habitats in Korea.

Hydrangeas thrive in salt air, too, and high humidity. Cape Cod is known for its blue hydrangeas. They flourish in Cornwall, the far western county of England that pushes into the Atlantic Ocean, and in the mists of Ireland, and in the cool summer temps of Brittany, France.

Hydrangeas from Ireland thrive in misty moisty summers

Then what’s a body to do to get good blooms in the States, Holmes? We can’t conjure moderate temperatures, ample rainfall and high humidity at will.

We must improvise. Scout the garden to find the very best site. Nothing too windy, too dry or too sunny. Good drainage, too. Even hydrangeas don’t like wet feet.

Look for a sheltered site with play of sunlight and shade. Shade is more necessary in the south than in the north.

Try to avoid eastern exposures. In cold winters, buds can be blasted by early morning sun.

Late afternoon shade revives these hyrangeas after an overdose of mid-afternoon sunshine which causes wilting and premature aging of blooms

Keep plants out of intense afternoon sun in summer. Wilting is more likely and blossoms age more quickly.

Plants in a hollow tend to get frost-bitten when cold lays on the land.

If large trees are nearby, consider the spread of their roots at the time of planting and several years from now. Large trees always win the race for water and nutrients. Pines seem to cause fewer problems.

This H. serrata ‘Grayswood’ planted near a sweet gum tree is only half the size of its sister plants that have no root competition. It blooms well only in years with good rainfall

That is some serious sleuthing, Holmes. And it must be done before the tragedies of the missing blooms.

Are we to deduce from all these clues, Holmes, that hydrangeas do not like extremes? Too much browsing, too much heat and drought, too much cold, or cold snaps at the wrong time, can all contribute to weakening the plant and preventing bloom.

Hydrangeas are rather like people, aren’t they? They don’t like extremes.