Time to Prepare Hydrangeas for Winter

It happened again – sudden freezing temps hit before my hydrangeas had a chance to harden off. Not a frost, but a solid freeze at 27 F that turned the birdbath turned into a skating rink. So sad to go outside and see what those temps did to my big leaf and mountain hydrangeas. Time to prepare my hydrangeas for winter.

Bigleaf Hydrangea After Freezing Temps

Those that aren’t planted in protected locations as I described in my other blog posts, HERE and HERE need a little help if I want to give them their best chance of having their buds make it through the coming winter to see flowers in 2021.

Exactly what does this mean right now?

PREPARE HYDRANGEAS FOR WINTER WITH SHRUB COVERS

SHRUB COVERS can be something to safely protect the plants from ice and snow, maybe even give them a few degrees of insulation.

The objective of shrub covers is to make your plant think it lives in a warmer zone. You do this by insulating it from fluctuating temps that can blast the flower buds. Of course, you need to wait until your plants have dropped all their leaves on their own before you can cover them. So even if your plant was blasted by an early season freeze like mine was, remember that leaf drop signals the plant is fully dormant. Take the time after leaf drop to clean up the base of the plant to prevent fungal spores from overwintering. That small chore will stop the spores from reinfecting your plants next season. This is also a great time to add some mulch to keep moisture in and prevent the plant from heaving during warm spells you might have.

Taking the need for dormancy into account, it may still be too early in your part of the country to install these covers. But it’s not too early to get those shrub covers lined up. By the time you need them, you might not have enough time to get it all done.

 WHAT DOES A SHRUB COVER LOOK LIKE?

 A-FRAME VERSION

A simple A-Frame made from discarded wood pallets is a popular DIY solution to prepare hydrangeas for winter. Lots of stores pile them up at their back door which you can salvage. Many gardeners like to build one on their own. DIY plans and ideas are all over the internet. Take a look at this one:

DIY shrub cover made from discarded pallets can protect your plants

Make an A-frame from discarded pallets.

You can leave the A-Frame bare to shunt off snow and ice. However, for colder areas the A-frame makes a great base to drape a tarp or insulating cover. If you do that, make sure you secure the tarp or cover against the weather with string or a bungee cord.

UNFRAMED DRAPE VERSION

Many gardeners prepare their hydrangeas for winter with an unframed drape. It’s held by the stems of the plant. It’s usually tethered at the base. Here’s one available at several online shopping sites:

Unstructured shrub cover draped over a hydrangea.

DIY CAGE VERSION

The winter preparation for hydrangeas I see most often is a DIY version made with chicken wire and a few stakes. You build a cage larger than your plant and then stuff the opening with leaves, straw, pine needles, etc. making sure you get the insulating materials down and around the bare stems. This takes a bit of care as you want to avoid damaging the tips where the sleeping buds lie.

DIY Shrub Cover Made from Chicken Wire and Stakes

INSULATING THE CAGE

Depending on where you live and where your plant is sited, you may want to insulate the outside of the cage by wrapping with bubble wrap or some other material. Also note that your internal packing materials (leaves, etc.) will settle during the winter. So many gardeners secure a cover over the top of structure.

Hydrangea Insulated With Top Covered

Cut a piece of Styrofoam (from craft stores) slightly larger than the top of the cage. Fit it above the cage and secure it to the chicken wire with twisties or bungee cords. Otherwise, heavy snow and rain will weigh it down and it will crush your plant. You can also use plywood or scrap lumber for this top. Make sure it’s not too heavy for the chicken wire to hold it up. If that’s too much for you, you can keep an extra supply of bagged leaves at the ready to top off your masterpiece from time to time.

EXACTLY WHEN TO PREPARE HYDRANGEAS FOR WINTER

Let the plants harden off over the next few weeks while you get things ready. But don’t wait for the last minute when time is short to get these items lined up for installation. There’s no way of telling when the on-line suppliers will run out and how much time you have to get yourself organized for this task. You can be ready to spring into action more quickly when you have your covers all planned out and ready to go. Plus it is more pleasant to work outside now before the temps really plunge.

THE NEED TO PROTECT OTHER HYDRANGEAS

Many times I get asked about the need to protect other old wood flowering hydrangeas like oak leaf and climbing hydrangeas. First of all, these plants are traditionally much harder to wrap. I have no clue how to wrap a climbing hydrangea – unless it was a new, small plant. And oak leaf hydrangeas can be quite large.

Well, here’s the good news: you don’t have to worry about them unless you have them in a zone colder than their hardiness rating. In my 30 years at this zone 5B home, those two varieties never failed to flower despite some significantly frigid winters. They have always come through.

This photo gives you a better idea of why that is. I took it at the same time I photographed the hydrangea macs and serrata (after the sudden freeze that blasted those plants). The foliage of the oak leaf hydrangea was completely untouched by that freeze and ensuing cold nights.

Oakleaf Hydrangea Untouched by Freezing Temps

In the second photo, you can clearly see what happened to a hydrangea mac in the back vs. the oak leaf in front of it.

Oakleaf Hydrangea After Freezing Temps With Blasted Bigleaf Hydrangea Behind It

I cover the subject of winter protection in my best selling book, Success With Hydrangeas, A Gardener’s Guide. You can order a signed copy here. It makes a great holiday gift for the gardener in your life.

Hydrangea happiness can’t start soon enough!

OTHER ITEMS TO NOTE

I am booking virtual presentations for 2021 and beyond. With the continuing Covid-19 health issues, this seems to be the way to go. The good news is that geography becomes irrelevant and I can easily discuss your favorite gardening topics from my home base to anywhere you are. Just click HERE to start the ball rolling to have me present to your group. And if any of the upcoming dates I have are public (very few are), I will post it on the calendar page of this site.

Lastly, if you want to read any of my writing about other than hydrangeas, you can find me at the Coast of Maine blog and Connecticut Gardener.