There are a lot of hydrangeas out there. A lot. In fact as far as I’m concerned, too many. This is of course, no surprise – it’s a highly appealing shrub that even non-gardeners want to grow. And if you hurry, there’s still time to pop a few into the ground before the season ends and we must begin our winter tasks of brush clearing and heavy drinking.
No matter how many new series are introduced by the breeders, the hydrangeas most commonly grown in North American gardens fall into six species. The good news is, you’ve probably encountered most of them, so hydrangea might just be one of those rare genera where a little knowledge can make you appear very knowledgeable indeed (sometimes it’s nice to one-up your Master Gardener mother-in-law over the Thanksgiving table).
Here’s the run down:
1) Big-leaf hydrangea (H. macrophylla) – these are your typical large flower heads whose firm, succulent blossoms you can’t help but touch as you walk by. The ubiquitous but hard working ‘Nikko Blue,’ lives here, and most of the new introductions that greet us at garden centers; but many flat lacecap varieties are also part of this group. (Macrophylla refers to the leaves, not the blossom.) I’ve got many. Again, too many. My very favorite is ‘Merritt’s Supreme,’ but as I am aware that fondness for such an ‘old’ variety brings my reputation into disrepute, I am happy to report that I’m planting the new ‘Grateful Red’ and ‘Fuchsia Glow’ as we speak. These bloom on old wood only, and can be cut low by a hard winter – so use a light hand and prune just after bloom.
2) Oak-leaf hydrangeas (H. quercifolia) – I love these native beauties with large, oak like leaves that turn deep red in autumn and bark that peels like cinnamon. Flowers are usually white, but age to pink. I grow ‘Snow Queen,’ the chartreuse-foliaged ‘Little Honey,’ and a species giant. I was planning on ponying up the cash for ‘Ruby Slippers,’ but then again, my kids need slippers too, and as they won’t stop reminding me, winter is coming. It’s ridiculous how many times I’m forced to choose between the whim of a child and a research-based plant purchase. Blooms on old wood.
3) Panicle hydrangeas (H. paniculata) – ‘Grandiflora’ was the old stately favorite, but in recent years, this species has taken off with varieties like ‘Limelight’ and ‘Pinky Winky’ – both of which I grow, and love. Paniculatas require more sun than H. macrophylla, are usually larger, the flowers more triangular, and they bloom on new wood – which means that our last two winters didn’t faze them. Lucky beggars.
4) Climbing hydrangeas (H. petiolaris/anomala) – A great choice for a north or east wall, these hydrangea take about three years to get comfortable, and then, oh boy. There is maintenance involved in this one folks, but clothing your house like an English manor (complete with window cutouts) might just be worth it for you. I’m currently quarantining one in the pot ghetto at my new house after experiencing its vigor at my last one. Beautiful yet suffocating – maybe I’ll find a tree for it to Kardashian instead. Blooms on old wood.
5) Mountain hydrangeas (H. serrata) – These Japanese beauties look much like the macrophyllas and also bloom on old wood, but are hardier. So if you teeter as I do in a Zone 7a world where a bad winter can crush all hopes of bloom with a macrophylla – this is the species you should be stalking. I grow ‘Bluebird,’ and ‘Tokyo Delight’ and so far so good. There are many other lace-caps in this group too, so know your varieties before you discuss this particular species in depth. With your mother-in-law.
6) Smooth hydrangeas (H. arborenscens) –This is where ‘Annabelle’ fits – the ultimate large, floppy mop-head hydrangea with a habit that, I admit, has never charmed the pants off me. I just don’t require that much from my flower-to-foliage ratio. Thankfully for the breeders, many gardeners disagree, and I have recently been made aware of new, stronger-stemmed varieties from Proven Winners – like the white ‘Incrediball’ and the pink ‘InvincibelleSpirit II.’ The latter also touts a worthy cause – a donation to Breast Cancer research with every plant sold. That’s worth trying it, and that’s exactly what I’m doing. One more thing going for this species is that it’s a new wood bloomer – so you can
A few other fine print items re: hydrangea care:
- More sun than you think – at least half a day and hopefully that of the morning variety – though paniculatas are quite happy in full, cool-climate sun.
- Give them all a good amount of water and mulch to conserve it.
Don’t forget to bring some of those gorgeous blooms inside to kick up your interior décor or present in a bouquet to your mother-in-law at Thanksgiving. With the exception of the smooth species, hydrangea blossoms make excellent cut flowers; but you must give them a little time on their stems to harden up before you pull out the shears.
- For H. serrata and H. macrophylla, bloom color is very much dependent on pH. The more acidic your soil, the bluer your bloom, and vice versa. You can change your pH using garden amendments such as aluminum sulfate (acid) and hydrated lime (alkaline) – but follow package directions carefully so you don’t make growing conditions for neighboring shrubs unbearable.
They’re an ego-boost – a shrub that makes you look like you know what you’re doing, even when you don’t. That’s worth a deep hole and a bit of attention with the hose don’t you think?
I live in Chgo. Have 5 hydrangeas [big leaf] ONLY ONE BLOOM!!!!!!! Big beautiful green leaves. What am I doing wrong? I didn’t prune anything thinking I’d have gorgeous blooms….WOE IS ME!!!!!
Hi Donna – Don’t despair, chances are you are not to blame – your winters are! Big-leaf hydrangeas bloom off laterals made on old wood. When those woody stems get cut back to the ground in a harsh winter, laterals can’t form and blooms won’t either. If you are set on big-leaf style hydrangeas, consider H. serrata cultivars (mountain hydrangea) with better hardiness, or the Endless Summer series that blooms on both old and new wood. H. arborescens (smooth hydrangea) cultivars bloom on new wood, are somewhat mophead-like but can be a bit floppy and heads are quite large. Otherwise, explore the wonderful world of panicle hydrangeas which deliver gorgeous blooms in late summer on new wood (can you tell they are my favorite?). Winters don’t get them down. I grow many – Limelight, Little Lime, Quick Fire, Pinky Winky, Diamond Rouge, Moonrock are just a few. Good luck! MW
What Is a good place to find different types of hydrangea! I look & look & only find the same 1!
I don’t tend to order shrubs online but prefer to use my local nurseries or scout through nurseries when I’m traveling. You can look on sites such as Proven Winners, First Editions, Monrovia, Bloomin’ Easy and Gardener’s Confidence and put in your zip code to find a local supplier.
Marianne, how MANY Hydrangeas do you have? The more I read, the more I wanted to see pics of your obviously gorgeous yard!
I’ve always wanted Hydrangeas and ordered 3 of the Nikko blue to try out, putting them into the ground today. They are in 2 at pots and are currently full of lovely green foliage. I’m in zone 7 I believe (middle of Oklahoma), what can i expect my first year? Oh, btw, love your writing and sense of humor 🙂
Hi Lisa – I’ve got too many to count, but have moved away from many of the macrophyllas as they are too unreliable bloom-wise for me (zone 6b/7) A hard winter will kill them back to the ground which means no blossom for next year. The rebloomers have not performed that spectacularly here, but I continue to trial them. H. serrata tends to have a better hardiness with the nice foliage of H. macrophylla – I grow Bluebird and Toyko Delight. I adore H. paniculata and H. quercifolia and grow many. Hands down my favorite paniculata is a fairly new one from Gardener’s Confidence Collection called Baby Lace. Fabulous height, strength and bloom. Limelight is a big favorite with many and I grow that one too – as well as the smaller Quick Fire and Little Lime. H. quercifolia foliage is just turning red right now and is gorgeous – I highly recommend trying one of these for your part sun areas, though they can cope in full sun with a bit of burn. Make sure to give your Nikko Blues a place where the soil is rich and there is a bit of shelter from afternoon sun and high winds. In the spring, WAIT to see how much die back you have before cutting the stems back to live buds. If you’ve got strong laterals developing you should have blooms next summer. Good luck – and thanks for the lovely words. I hope you find more articles of interest on the site, and make sure to subscribe for my latest articles and newsletter!