How to Prune Hydrangeas, Change Their Color, Revive Wilting Blooms, & Other Tips and Tricks that Will Make You a Hydrangea Boss!

The endless supply of hydrangeas in our yard is one of my favorite things about summer – I love being able to walk out our back door one minute and have a beautiful bouquet of hydrangeas prettying up our home the next! Whenever I share pictures of my hydrangeas on Instagram and Facebook, I get lots of questions about things like pruning, changing hydrangea colors, and making cut hydrangea blooms last so I decided to take those commonly asked questions and answer them today! (affiliate links included in post – full disclosure statement available {here})

I’ll kick things off with a question that you should definitely read the answer to if you’re thinking about pruning your hydrangeas this fall…

Pruning Hydrangeas: When’s the Best Time & How Much Can I Prune Off?

The answer to this question isn’t as simple as you might think! How aggressive you can get with your pruning depends upon whether you have a variety of hydrangea that (1) flowers on old “wood” (stems from the previous year), (2) flowers on new wood, or (3) flowers on a combination of new and old wood (Endless Summer hydrangeas). For hydrangeas that flower on old wood like these pink and blue mophead hydrangeas in our backyard,

 it’s ok to prune off dead stems or blooms at any time (prune close to the bloom) but if you want to do more significant pruning because your hydrangea bush is getting too large, it must be done in the summer (before August to be safe!). Starting in late summer/early fall, the buds for next year’s blooms start to form so if you prune at that time, you’ll be cutting off those precious buds and will have a big green, leafy but bloomless bush the following summer! 

If you have hydrangeas that flower on new wood like Limelight hydrangeas or the Annabelle hydrangeas along the walkway in the front of our house, the entire bush can be cut close to the ground in late fall or early winter and they’ll still grow and bloom just fine the following summer. Can you believe that we cut these down to only about a foot above the ground the winter before this?

One of the negatives of Annabelle hydrangeas compared to some other types is that they have thinner stems and tend to be a lot more floppy. One little tip to pass on that we figured out by trial and error is to actually prune them to only about 2-3 feet from the ground instead of super close to it. While they grow back fine either way, we’ve found that leaving some of the old growth serves as a support for the new growth in the spring and summer so they’re not nearly so floppy. You can see the difference in how much more upright they are this year when we left a few feet of old growth when pruning the year before:

And if you’re looking for a pruning tool recommendation, my gardener (aka my husband) prunes our hydrangeas with {these pruners} that have longer blades to get the job done quickly and telescoping handles that are super helpful for pruning our taller hydrangea trees. 

How Do I Get My Hydrangeas to Be Such Pretty Shades of Blue & Pink?

The color of a hydrangea’s blooms depends upon the pH of the soil they’re growing in (unless they’re white, in which case they’ll always be white!). When the pH level in the soil is higher, you’ll get pink blooms and when pH levels are lower, you’ll get blue blooms. And the pH can change from year to year depending upon things like the type of fertilizer or mulch that you’re using. Last year every single hydrangea in our backyard was a pale blue/purple but this year we got some gorgeous pinks:

along with some seriously stunning deep purples:

I’ve always left the color of my hydrangea blooms up to chance (I think the big change in the past year is because we used a different type of mulch) but there’s actually a way to mess with Mother Nature and get the color blooms that you prefer. If you want pink blooms you can raise the pH by sprinkling garden lime such as {this} at the base of the plant or using a product such as “Color Me Pink” available {here}. If you want blue or purple blooms, you can lower the pH by applying a soil acidifier such as {this}, aluminum sulfate (available {here}), or “Color Me Blue” available {here}. I’ve also heard that coffee grounds can do the trick! The key is to apply them early in the growing season and re-apply throughout the growing seasons but water them in well and don’t go overboard because too much can harm your plants.

If you want to monitor your soil’s pH during the growing season you can use a probe like {this one} I have that gives readings on both the pH of the soil and the moisture content:

How Do I Keep Deer from Eating My Hydrangeas?

We have lots of deer that wander through our yard and they LOVE to eat my hydrangeas, especially right after they’ve just started to bloom:

I’ve tried a few different things to keep them away but the one that works best for me is Bobbex in a ready-to-use pump sprayer (available {here}). It is truly the most disgusting smelling stuff ever but it does the job! I spray mine early on in the season before my hydrangeas start blooming and then once a month throughout the growing season. Between our front and backyard we have a ton of hydrangea bushes but it only takes me about 15-20 minutes to spray them all. You can read more about using Bobbex along with other tips for repelling deer in {this post}.  

How Do You Make Cut Hydrangea Blooms Last?

It’s so disappointing to have a beautiful bouquet of hydrangeas that starts wilting just a few days after you put it together. Here’s what I do that helps keep my cut hydrangea blooms last (sometimes for two weeks or more!):

1. Clip your blooms in the morning and cut the stems on the diagonal. A lot of gardeners recommend using a knife but I’ve always thought that was kind of difficult and awkward. Instead of using typical garden pruners, I like using {these kitchen scissors} – by cutting the stems near at the base of the scissors where there’s a semicircle, it acts like a guillotine and gives a clean cut without crimping the stem. And the two blades pull apart so you can throw them in the dishwasher for easy cleaning. 
2. Remove any leaves that will be below the water line of your vase – this helps keep away rot and bacteria.
3. Use a vase that has been washed in warm, soapy water (not just quickly rinsed out from its last use).
4. Add a packet of flower preservative to the water if you have it or, if you want to go all out, dip each stem in boiling water for 30 seconds and then in Alum powder (available in the spice aisle at grocery stores) before putting them in your vase.  
5. Change the vase water every other day. 

How Do I Revive Wilting Hydrangeas?

While most of my hydrangeas do well using the tips I outlined above, I sometimes get an outlier or two that unexpectedly wilts just a few days after being cut. There are several different ways to revive wilted hydrangeas like dipping their tips in boiling water or submerging the whole bloom in cool water overnight but the trick that works just as well for me and is easier is to simply recut the stem (on the diagonal again) and put it in a glass or small vase of very warm water (I use the hottest water that I can get from the tap) for several hours. This will typically perk up your bloom by the end of the day at which time he can rejoin his friends in the bouquet!

And finally, I’m wrapping up this Q & A with one last question – probably the one that I hear most often because it’s the most frustrating… 

Why Didn’t My Hydrangeas Bloom this Year?

It is SUCH a bummer when hydrangea season rolls around and your bushes start to grow and get big and leafy but…. there are no blooms. Here are a few of the reasons it can happen:

1. Pruning at the wrong time. If you have hydrangeas like mopheads that grow on old wood and you pruned them too late in the season the year before, you probably inadvertently removed the buds that had started to develop for the following year. 
2. Using too much fertilizer. Some fertilizer is a good thing but too much is not! I tend to err on under-fertilizing vs. over fertilizing and only do it once a year (in spring) even though the instructions of most fertilizers recommend more frequent use. I don’t know of any magic fertilizer for hydrangeas but I’ve been using Jack’s Blossom Booster (available {here}) and my hydrangeas have done well with it!
3. Frost damage. A late frost can damage developing buds so that they never bloom. In cold climates, before winter you can try mounding up mulch or straw about a foot high around the base of the bushes to protect and insulate the developing flower buds. 
4. Too much shade/not enough sun. Hydrangeas need a certain amount of sunlight to bloom so if yours isn’t getting several sunny hours a day, that could be the problem – you might need to try a different spot in your yard. 

Do you guys have any other questions that I missed or hydrangea tips or tricks of your own to share? Let me know in the comments! And if you want to save the link to this post so it’s easy to find when spring rolls around, I created a Pinnable image at the end of this post! 

Now go forth and enjoy your Labor Day weekend!