Hydrangeas over winter

Today is the start of something really interesting which we’ll be covering over multiple posts and videos over the winter and beyond. Hydrangeas. However, as we have to start somewhere, I thought a brilliant place to start might just be winter and how we look after our plants because that way we can make sure we give them the very best start for next season to help get the very best out of the shrubs – blooms and all.

So this has come about because I’ve had loads of queries over on youtube about why I bring my hydrangea into the greenhouse for winter and should everyone be doing that. I figured rather than keep answering all the individual question (which means lots of folks miss out on the learning), I’d answer all the questions in one. So here we go… hydrangea and overwintering. You might want to grab a cuppa and a biscuit, we’ll be here a while.

Right the very first thing you need to know about is what type of hydrangea you have, because the different types need different care. Now in my garden this year, I only have two types:

• Mopheads (Hydrangea macrophylla), and
• Hydrangea paniculata

however, the last few years we’ve also had

• Lacecaps which are also a type of macrophylla

So let’s talk about the different types then starting with macrophylla which is essentially the big leaf hydrangeas – both mophead, which is probably the most common you see in the UK and the lacecap.

The mophead hydrangeas have a big ball like bloom, usually in pinks through to blues but you can also get white varieties. The leaves will turn autumn colours and drop before winter as the plant becomes dormant. The flowers will turn brown and dry.

Now I think the most interesting thing about the mophead hydrangea is the fact that their colour is not predetermined. You may buy it with beautiful blue flowers or with hot pink BUT… that does not mean that it will carry on being those colours in your garden. The flower colour is determined by the PH of the soil which in turn affects the uptake of aluminium. How amazing is that?

This is a little experiment we are going to carry out this year so stay tuned for more on that. But back to winter thoughts…

So now that you know what the mophead hydrangea looks like, the next thing you need to know is that this hydrangea blooms from old-growth, meaning you will already see buds appearing on your plant before winter sets in. This is why I move my hydrangea into the greenhouse over winter, as I want to protect those buds from being damaged by the frosts and cold spell over winter. Now let me be clear here, you do not need to move these into a greenhouse, you could protect them by covering the plant with fleece. I choose to move them as in previous years I’ve found the fleece wasn’t as effective as I’d like, but this is most likely down to the individuality of my garden and how frost hits it and of course me and my ability to wrap fleece around a plant 🙂

The most important thing to remember is that if you do move your hydrangea inside over winter, you must keep it in an unheated area like an unheated greenhouse or garage. Don’t bring it into a heated conservatory or similar as the plant does need those colder temperatures so that it will go dormant and prepare for the next season.

The other thing I recommend is leaving the spent blooms on the plant, as unsightly as they may be, they do offer a little protection from frost for the buds underneath. And come spring, you can trim them off, back to a healthy bud. And bonus, if you have lacecap hydrangeas, winter care is exactly the same as with the mopheads, protect from frost, leave the blooms in place and let the plant go dormant over winter. We don’t have any lacecaps in our garden at the minute, unfortunately, they didn’t survive the beast from the east 🙁 but you can identify these by their flowers. The bloom forms a circle of larger flowers around the smaller central bloom, hence the name lace cap 🙂

Now let’s flip this over and talk about paniculata. These have cone-shaped blooms usually in white or white with a tint of pink or green and creamy colours. Unlike the mophead, the colour is set and can’t be changed.

For winter care, the thing to be aware of here is that these hydrangeas bloom from new wood, which means you don’t have to protect the stems quite in the same way as with the macrophylla. In fact, you are actually recommended to prune these back at the beginning of spring to encourage new growth and therefore new blooms. What we will do for winter protection though, just like we do with the macrophylla is to mulch the pot to protect that base, you can use straw or autumn leaves etc. You want a good couple of inches covering that base of the plant to protect the delicate roots underneath. Also if you have your hydrangea in a pot, you should wrap the pot to protect the roots from the cold as pots are more susceptible to the cold than plants in the ground. You can wrap the pot with fleece, bubblewrap etc, just something to help a little with the cold.

So, now you know, the type of hydrangeas you have will determine how you treat them over winter. You don’t have to take them inside but it is good to protect any delicate areas from frost.

OK off you pop, to the garden with you 🙂