Sudden Freeze After Days of Warmth

– Posted in: Garden chores, Hydrangeas, Weather

74F Last Thursday, 16F Predicted Monday

Cold climate gardeners, we knew this was going to happen, didn’t we? After the incredible, pinch-me-I’m-dreaming spell of beautifully warm weather, the real March weather is coming back with a vengeance. I don’t think it got quite as warm here as it did other places in my general area, but it got warm enough to coax the hydrangeas into bud.

Hydrangea leafing out

This Hydrangea macrophylla cultivar took the first warm spell a little too seriously.

Last spring I agreed to trial ‘Summer Lace’ (Hydrangea macrophylla ‘Shugert’) and ‘Blue Heaven’ (Hydrangea macrophylla ‘Blue Heaven’) because I wanted to test out the advice in Hydrangeas in the North: Getting Blooms in the Colder Climates. Author Tim Boebel has spent years trialing all sorts of hydrangeas, but despite his subtitle, he gardens in a zone 6 climate–warmer by at least one zone than mine. I wanted to see how his advice held up in my colder climate.

But the decision to move and the ensuing upheaval caused me to change my plans. Instead of planting those two trial hydrangeas last spring, I potted them up and planted them in the new garden last fall. So I’m taking pains to make sure they survive long enough for me to apply Tim Boebel’s advice. That’s why, when I learned the predicted low for Monday was 16F degrees, I decided to protect the hydrangeas with a mulch of leaves.

Hydrangea mulched with leaves

The unpruned branches of this hydrangea help keep the leaf mulch in place.

When I moved to this new garden, there were some hydrangeas already planted here. I am mulching those as well, so I have a chance to see what they look like.

In general, I don’t like to grow plants that have to be babied. It just adds a layer of stress to what should be an enjoyable endeavor. But sometimes I will go the extra mile because I’m curious about a plant or a garden procedure, and this is one of those times. How about you? Are there any plants you’re going to protect?

And I have to say, that glorious spring weather kind of spoiled me. To think many gardeners start spring this early every year! I’m trying really hard to remember their summers are hotter.

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

Comments on this entry are closed.

Parsnip Love March 27, 2012, 4:28 pm

I’m in zone 7a and we have also had freakishly warm weather that is confusing our hydrangea (also an “Endless Summer”). It just budded out this last week when it was 75-80 and now last night it dipped down to 28. Poor thing. Hopefully it will regroup. It has been so warm that my rhubarb is also mixed up and already tried to flower!

spurge March 27, 2012, 11:59 am

I have also been terribly spoiled by the warm weather of the past couple weeks – I feel betrayed and resentful that it’s actually down in the FIFTIES now (which normally would be considered quite warm for March)! So silly really, but there you go.

Yael March 27, 2012, 4:40 am


We don’t have temp swings quite that wild where I live, but I was told that we had about 5 inches of snow last week and that it is still a cold rain with snow mixed at times after having had temps up to 65. Hope you manage to protect your hydrangeas.


Andre March 26, 2012, 6:27 pm

The weather’s been super here too.(Ottawa).
But serious gardening still a few weeks away.

Gaz March 26, 2012, 12:50 pm

Brrrr, does not sound good at all.

Over here in the UK we are having a warm spell with a high over the country. I hope your cold spell isnt too bad.

Phil (Smiling Gardener) March 26, 2012, 12:44 pm

I’ve been telling everyone to hold of on planting the veggie garden for this very reason. Still a bit of winter left it seems. Your hydrangeas look like they’ll be happy with that protection.

DJ/Meander Mountain March 26, 2012, 11:56 am

I rarely coddle plants, although I do try to protect them from deer and other critters as much I can, mainly by placing the susceptible ones closer to the house. Other than watering during extended periods of drought, I pretty much let plants tough it out on their own. If a favorite plant is struggling, I will have mercy and intervene…. up to a point.

Frances March 25, 2012, 2:42 pm

Best of luck with the hydrangeas, Kathy, and keep those blankets on the beds! HA, a little gardening joke there. Even in zone 7a, the H. macrophyllas can get zapped by a late freeze in April. We often cover ours with the Christmas tree branches in December after the holiday. Ours are still covered, even with nearly 90 degree temps here. Some of the newer ones will bloom on new wood, like the Endless Summer group. We will be watching your experiment, nothing is a given with the weather anymore.

Carol March 25, 2012, 11:55 am

Whatever will be, will be… I can’t believe that temperature swing you are going to have. That’s brutal and cruel!

Deborah Banks March 25, 2012, 10:36 am

They keep revising the forecast for Monday downward. It’s now predicted to be 9 degrees in Oneonta Monday night, which means about 4 degrees up here. Yikes! I have peonies coming up, a Dr. Merrill magnolia starting to bloom and even the later ‘Ann’ magnolia is starting to break bud, delphiniums are 5 inches tall, plus lots of early things are in bloom like primulas, daffodils and leucojum. The bulbs can take care of themselves, but I plan to try to save my magnolias with row cover wraps and old blankets over that. And we’ve been planning to take down 2 or 3 smallish spruce trees that are growing into our view, so we’re doing that today so I can lay the branches on some of the beds. My newest bed of primulas did some frost heaving this winter, so this should help. The branches I used after Christmas have dropped too many needles now to help much.

Melissa March 24, 2012, 10:12 pm

Yikes! The weather has been dreamy here too (Southwestern Ontario). I see Monday shows a dip below freezing. I’ve got row covers over my veg seeds in the raised beds. Everything else shall fend for itself. Like you, I don’t care for coddling plants. I don’t even water the perennials. I say thrive or move on! We have been spoiled this year with this warmth.