We have had a few nights where the temps have dipped into the high 30s, a sobering reminder that it’s time to prepare hydrangeas for winter. Specifically, it’s time to wrap susceptible bigleaf (macrophylla) and mountain (serrata) hydrangeas. Those that aren’t planted in protected locations as I described in my other blog posts, HERE and HERE need a little help if the flower buds are to have their best chance of making it through the coming winter.
Exactly what does this mean right now? SHRUB COVERS: something to safely protect the plants from ice and snow, maybe even give them a few degrees of insulation.
PREPARING HYDRANGEAS FOR WINTER WITH SHRUB COVERS
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. 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 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 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.
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:
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. You need to be 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.
INSULATING THE CAGE
Depending on where you live and where your plant is sited, you may want to insulate the outside of the cage with bubble wrap or some other material. Also note that your packing materials will settle during the winter. So many gardeners secure a cover over the top of structure. 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. Barring that, you can keep an extra supply of bagged leaves at the ready to top off your masterpiece from time to time.
THE NEED TO PREPARE 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 is a new, small plant. And oak leaf hydrangeas can be quite large.
You can use the same technique of shrub covers. But 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 serratas after a sudden freeze one season that blasted those plants. The foliage of the oak leaf hydrangea was completely untouched by that freeze and ensuing cold nights.
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.
WAITING 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 things lined up for installation. There’s no way to tell when 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 before the temps really plunge.
I’m delighted to tell you that I will be speaking in person at the November 17th meeting of the Connecticut Horticultural Society (CHS). The topic is Shrubs, the New Perennial.
The meeting will be held at Emanuel Synagogue Auditorium, 160 Mohegan Drive, West Hartford, CT. CHS members attend free of charge. Non-members are asked to donate $10. Meetings are also free to full-time students with valid ID. Social time begins at 7pm, followed by the speaker program at approximately at 7:30pm.
I am booking virtual presentations for 2023 and beyond. The good news is that geography becomes irrelevant with virtual talks. I can easily deliver your favorite gardening topics 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.
Thanks for reading.
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