The flower buds of bigleaf hydrangeas (Hydrangea macrophylla) are formed in late summer and early fall but are very temperature sensitive. Both to winter cold, and even more commonly in milder zones, to late spring frosts or freezes. Folks in zone 6 or below need to provide some sort of winter protection to ensure these latent buds are not cold damaged. Lately, unsettled spring weather (warm spells followed by sharp cold) has even made that a requirement in milder zones. Reblooming or remontant hydrangea cultivars can offset this to some degree but the flowers that develop on the new growth often appear very sparsely or not until very late into the season

Hydrangea macrophylla blooms on old wood and the buds are often winterkilled. Hence, no flowers

Is there a way to prevent killing the buds in winter?

Hi , for first in yrs my Endless Summers are blooming, with a Very wet Spring and no Winter Protection

hyed, may I ask, in what zone are you gardening and where?

6a, just NW of boston

I see.

You must not have gone through such an extreme winter as we suffered through in the Chicago area. -33F, brrr....

My Endless Summer plant has never ever bloomed since I planted it about 7 years ago... :-(

Glad it bloomed for you. May you enjoy many repeat performances!

Thank you gardengal. Sorry it didn’t seem like the link came through the first time. Got it now and will read.

I only linked to info about winter protection in my second post - I just remarked on the need for it in my first :-) There are scores of websites that will suggest various methods. And searching this forum will turn up many posts that deal with the same issue.

Something unusual happened this growing season.... Last growing season when I was checking out other people's Macro's, very few had blooms in my area. The ones that did, had only maybe 1 to 3 blooms on the entire shrub.. This growing season, I'm seeing blooms on almost all macros in my area and they are covered in blooms. It's a drastic difference from last season.

There's this one house that I drive by on my way to work that has a hedge of them. Last summer they did not have a single bloom. This year they are covered in vibrant blue blooms. I've never seen a single person in my area winter protect so it's not from that. I'm guessing it was due to a mild winter and no late season frosts?

Unprotected macros will loose flower buds when temperatures get too cold. This can happen in the middle of winter, if the plants get hit by an unexpected very early frost in the Fall or if the plants get hit by an unexpected late frost in Spring. The fact that everyone's macros were affected suggests that weather had something to do with the problem last year. And yes, the weather may have been "better" on the flower buds this time around. You should be able to go into varioues weather websites and review how was your weather this Spring (2019).

The only answer is to replace them with newer, more reliable blooming varieties. I'd recommend the newer Endless Summer varieties i.e. Bloomstruck, or anything in the Proven Winners Let's Dance series, i.e. Rave, Rhythmic Blue. These varieties were bred in Michigan and selected for reliability. They are more likely to flower even if the flower buds are killed back in the winter or spring. Life is too short to grow hydrangea that don't bloom.