If you had to guess how many hydrangeas were sold in the United States in a year, what would you go for? Maybe 100,000. Perhaps half a million. Shall we push it to a million or two?
That was close to my guess too, but even I was very far off the mark. According to a report for growers released by the University of Tennessee Extension Service in 2021, more than 10 million hydrangeas are sold in the United States each year.
These plants come from more than 1,500 nurseries country-wide.
And let’s say that only about half of these hydrangeas get planted into our gardens (with the other half being gift hydrangeas that never make it past the Easter or Mother’s day fervor); that’s still five million hydrangeas planted in a year.
I’m doing my part to keep this trend going this year by planting a Hydrangea macrophylla in my garden. If you’re also planning to bring a new hydrangea friend into your life this year, let me show you my best tips.
When can I get my hydrangea in the ground?
The nice (and also a bit weird) thing about hydrangeas is that you’ll find them for sale at any time of the year. The garden centers near me stock it almost non-stop, from January through November.
But since it’s a shrub, and since young plants are fairly sensitive to cold, we should plan to plant them either in spring (once the danger of hard frost is behind us) or in the fall (about six weeks before the first frost).
Technically, we could plant hydrangea shrubs in the summer, but with one caveat. We must absolutely not forget to water them regularly and sufficiently. These are not a “set it and forget it” type of plant. And just like they’re sensitive to frost, young hydrangeas are also sensitive to scorching heat.
Hydrangeas are in active growth from March through September, so that’s when we’ll start seeing the fruit of our labor.
Help! I bought a dud!
Ok, so now you know when to plant hydrangeas and you go to the store and come home with something that is labeled hydrangea, but looks like a sad pack of sticks.
You may be wondering, Is this hydrangea dead? Can I still plant it?
Yes, you can. Your hydrangea is not dead, just dormant.
There are three types of hydrangea that you’ll find for sale at the garden center.
First, you have old wood hydrangeas.
These are shrubs that flower on last year’s growth. Most of them should already be showing buds in spring, in different stages of leafing up.
I wrote about them at length in this article; but just as a recap, here’s what they are:
- French hydrangea (Hydrangea macrophylla)
- Climbing hydrangea (H. petiolaris)
- Rough leaf hydrangea (H. aspera)
- Mountain hydrangea (H. serrata)
- Oak leaf hydrangea (H. quercifolia)
Then we have new wood hydrangeas.
If you think you bought a dud, you probably bought a new wood hydrangea. These are shrubs that will bloom on this season’s growth; which means that if you buy them in spring, they will still look like an unfortunate collection of dead sticks.
Buy them anyway and watch them transform into radiant shrubs in your garden.
The most common new wood hydrangea are:
- Panicle hydrangea (Hydrangea paniculata) and
- Smooth hydrangea (Hydrangea arborescens)
Then you have the so-called Mother’s Day hydrangeas or gift hydrangeas.
Gift hydrangeas are tricky because they’ve been forced to bloom in greenhouses all through the winter. And this is often done by over-fertilizing them, which comes at the expense of longevity.
So if you think you’re buying your way to a summer blooming shortcut, think again. You’re buying short-term gratification. While it’s not impossible to get these hydrangeas established in the garden, they would be my last choice … and only if dormant hydrangeas weren’t available.
What’s the best spot for a hydrangea?
I think hydrangeas get a bit of a diva reputation, completely undeserved in my opinion.
Yes, they need sun to bloom. But they can’t handle too much sun.
Yes, they need plenty of water to grow vigorously. But they can’t handle continuously damp roots.
Ok, maybe that reputation is a bit deserved.
But the best spot for a hydrangea is still not hard to attain in most gardens. If you have a place that gets full sun in the morning (for about three hours, ideally) and part shade or dappled shade in the afternoon, that is the ideal location for this shrub.
What zone you’re gardening in also plays an important part in positioning your hydrangea.
The further north you are (Zones 4-5), the more sun your plant can handle, even in the afternoon.
The further south you are (Zones 7-8-9), the more you should aim to protect your hydrangea from full afternoon sun (which may scorch the leaves).
Keep in mind that the more sun this plant gets, the more water it will need in order to keep looking like a luxuriant leafy shrub and not a scrawny eyesore.
Now if the sun is in short supply in your garden, don’t worry. You can still plant a hydrangea. There are some cultivars that have been bred to tolerate lower sun conditions. But please remember that this doesn’t mean full shade.
No hydrangea will ever thrive in full shade.
On the other hand, if your garden gets a lot of sun and heat, with little to no respite in the afternoon, a panicle hydrangea would do better than a Hydrangea macrophylla. The Hydrangea paniculata reaches its peak flowering with about five hours of sun a day.
Can I plant a hydrangea close to my house?
Yes, technically you can. Hydrangeas have shallow roots that won’t encroach on a normal house foundation.
However, you should still space them away from the house, just from an esthetic and airflow point of view. You want sun and airflow to be able to reach the entire plant, with plenty of space left behind it as well as around it. Plus, it doesn’t really look good when you sandwich it against a wall.
Since we don’t prune hydrangeas hard, don’t rely on this to regulate an overgrown shrub. There are hundreds of cultivars out there, of varying sizes, so always check the label of what you’re buying for a mention of the maximum size of that specific plant.
Sometimes that could be three feet (below one meter) and sometimes it could be 10 feet (about 3 meters) for larger cultivars.
That’s the size that the plant will reach at maturity, so this may not happen within the first three years while it’s getting established. But good planning will save you the headache of having to transplant them a few years down the line.
Location can make or break a hydrangea’s blooming season. And choosing the right location is the first step in avoiding the dreaded question, why isn’t my hydrangea blooming right?
What kind of soil does hydrangea like?
I think there’s this common misconception that hydrangeas will only thrive in acidic soil. It’s not that fussy.
Hydrangea will do well in most soil types, including alkaline and acidic soil. The only difference will be in the color of the blooms.
In acidic soil, the color tends to be more blue, while in alkaline soil, pink blooms will be dominant. Sometimes, the color that you get may go through a “blurple” phase (a combo of blue and purple hues). That’s my favorite!
Above all, hydrangeas do well in moist soil that is still free-draining. So we need to find a balance between soil that holds water, but doesn’t hold it for too long.
But what’s the problem with holding water? I thought hydrangeas like water!
Yes, they like drinking water. But they don’t like having their roots submerged for hours on end. It is possible to overwater a hydrangea that’s been planted in slow-draining soil.
Whether your soil is too crumbly and light or too heavy and compacted, adding some soil amendments will very likely fix that. And I don’t mean fertilizer. I mean incorporate some moisture-retaining organic matter, such as finished compost or leaf mold.
Now that you know when and where to plant your hydrangea, let’s move on to the how part. I’m planting mine in spring, but if you’re doing this in the fall, the steps you need to follow are the same.
Step 1: Prepare your hydrangea planting site.
Admittedly I could have said “dig a hole and that’s it.” But I think preparing the planting site takes a little bit more thought than that.
At least, I like to put more thought in it because:
- Shrubs, even small ones, are getting more and more expensive nowadays (understandably, since they’re very resource intensive). I want to save myself the extra expense of rebuying them, so I give them every chance I can to succeed on their first try.
- I take it as a personal affront when a plant doesn’t thrive on my watch.
Once you have chosen the best location for your hydrangea, in terms of sunlight, soil, your particular aesthetic consideration and the size of the mature plant, it’s time to start digging.
But don’t dig too wide and definitely not too deep. Keep in mind that you will want to plant your hydrangea at the same level as it’s been planted in the nursery pot.
I just like to use the nursery pot as a gauge, by placing it in the ground before I take the plant out. That way, you’ll get a perfect mold of where the hydrangea rootball will go; although sometimes I dig a couple of inches deeper and wider.
If your soil needs amendments (like the ones we’ve talked about above), now would be the best time to incorporate them into the soil. Do so by digging a larger hole and mixing the soil with the newly added organic matter as evenly as possible.
Add a sprinkle of gardener’s star dust.
And speaking of small investments that pay off big time, I’ll follow the lead of my colleague Tracey and add a sprinkling of mycorrhizae to the planting hole.
Tracey has already written extensively about this secret gardening potion, so I’ll just give you the cliffnotes: mycorrhizae is short for mycorrhizal fungi. It can come as a powder, but the one I bought is pebble-shaped.
In an undisturbed garden, their networks would occur naturally and develop over time. But unless we’re talking about The Secret Garden, we really don’t have undisturbed gardens anymore. Even me digging this hole to plant my hydrangea means that I’m disturbing the fungal networks in the soil.
Mycorrhizal fungi increase the strength and surface area of the root system right from the get-go. This means that this young hydrangea will get established faster and stronger.
This is very potent stuff, and just a simple sprinkling is enough. Add it to the planting hole just before you plop the plant in. The packaging should tell you how much you need to add.
My colleague, Tracey, swears by this brand of mycorrizah which you can easily order from Amazon here.
Step 2: Get your hydrangea in the ground.
Gently pull the hydrangea out of the nursery pot. If the root ball is packed tightly and looks too compact, or if it has started circling around the bottom of the pot, you can use your fingers to gently loosen it up. This will encourage the roots to spread out faster while also helping with better water absorption.
But don’t worry if you can’t. The root structure on this hydrangea was pretty compact, so I trust the mycorrhizal fungi to do the heavy lifting.
When you place your hydrangea in the ground, make sure that the crown is always at ground level. If you bury it too deeply, too much of the stem remains wet for too long, which may cause rot.
If you don’t bury it deep enough (less often, but it does happen, especially if you hit rock), the roots will be exposed. Again, it will not lead to a good outcome.
Backfill the hole with soil and press gently to firm it down. Then give it a good watering to help the soil settle and remove any air pockets.
At this point, you’ll probably need to top up the soil even more and repeat the watering step.
Step 3: Water and mulch
If I mention watering one more time, you’ll probably think I’ve lost the plot. But I want to impress upon you how important water is for getting a hydrangea established.
One more step to help insure that the soil stays adequately moist is to apply a layer of mulch around the hydrangea. Whether you’re using compost, wood chips (not wood bark), leaf mold, dry leaves (if you’re planting in the fall) or pine needles.
Mulching is especially important if you’ve planted your hydrangea in a sunnier spot.
Not only will it help retain moisture in the soil, but it will also help modulate the fluctuations of temperature at soil level (in all seasons). As I mentioned, hydrangea roots are fairly shallow; and extreme fluctuations that affect the roots will have a negative effect on blooming.
Step 4: Aftercare
I know I talk a lot about aftercare when it comes to taking cuttings (including hydrangea cuttings). But in this case, aftercare is really important for a newly-planted hydrangea too.
Make sure you water it often enough for the next couple of seasons, especially if you’re planting it in spring. This is essential for helping the shrub to establish.
The label hydrangea on the hydrangea that I’m planting says that it’s frost resistant. But I’m going to keep an eye on the weather app anyway. If we have a hard frost forecast, I have a burlap cloth ready to cover the plant.
Keep in mind that it may take a full year – or more – for a hydrangea to start producing blooms at full capacity, so there’s no reason to panic if not much happens in its first flowering season.
Should I fertilize my hydrangea when I plant it?
No, this is not the best time to fertilize your hydrangea.
First of all, because it needs to focus on root development (underground growth) rather than on leaf or bloom development (above ground growth).
I’ve also started to notice that new wood hydrangeas are sold pre-fertilized. Can you see the little pellets on the surface of the soil? That’s slow release fertilizer. I wonder if that was always customary or if it’s just a recent change to satiate our need for rapid results right away.
And if you’ve added finished compost and mycorrhizae to the planting site, there are plenty of nutrients in the ground to make that happen. I told you it was gardener’s magic dust.
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