This past weekend we were busy at The Blomidon Inn in Wolfville, doing tours of their gardens (which are open to the public, dawn to dusk daily. You don't have to be a guest, dining or shopping there, although I highly recommend the Inn and its House of Gifts for all those things and more). Among the highlights of the gardens are the 'Hydrangea Hill' plantings outside the Inn's Conference Centre. We had quite a few questions about hydrangeas, so I promised a blog post. And here it is.
Hydrangeas are one of my favourite genera of woody plants, although they aren't all equal in terms of how to grow them and how easy they are. They do best with quite a bit of sun, and lots of moist, organic-rich but well-draining soil. Those are the very basics of hydrangeas, but there are exceptions and there are particular pointers for choosing the best plants for your conditions.
There is one creeping/climbinb hydrangea, Hydrangea anomala ssp. petiolaris. It does well in dappled shade and/or morning sun with some afternoon shade. Once established, it is a vigourous grower, and can be trained to grow up a trellis, a hardwood tree, a wall, or other place where it can grow well-supported. It's hardy to zone 4 and produces lacecap-type flowers in pure white. Highly recommended.
Another easy-growing selection is the Annabelle hydrangea. (Hydrangea arborescens, 'Annabelle' and related cultivars). This species is known for its vigourous growth and large white heads of pure white flowers. I have two of this species growing in full sun and they are almost too vigourous, as I have to prune them to curb their size every spring. They spread gradually, and can have massive flowerheads, which frustrate many gardeners because they tend to flop.
You can control the floppiness with some corrective pruning to strengthen stems. Prune them in the fall after they've finished blooming, and you won't have the messy stems to look at all winter, and it will be one less chore to do in the spring. I do prune mine in spring, but I don't cut back all the stems, but thin out a number of them, and this also helps to make the flowers larger. Some people cut their Annabelles almost to the ground, but the stems aren't as likely to strengthen as they are if you only cut them back by a couple of feet each year.
With Annabelle hydrangeas, it doesn't matter what the soil pH is--the flowers will be white and that is that. There IS one exception, and that is a recently developed pink-flowered form, Invincibelle Spirit. It has dusty rose flowers, and blooms on new wood so it's touted for being reliable in blooming. I planted one this summer and I'm withholding judgement for now. The stems seem very floppy so far this summer (which is a common complaint that I've heard from others trying this plant), but the dusty-rose coloured flowers are pretty. I'm interested to hear from other gardeners who have had Invincibelle Spirit for more than one growing year.
This is a lacecap called 'Edgy Orbits', one of the Proven Winners plants. It is noted for having double flowers, pink edged with white IF the pH is alkaline enough for it. I have only seen it blooming pink, but it's fairly new to this area and I suspect it would turn quite blue in my soil.
'Tokyo Delight' is an older lacecap variety, apparently, but I only saw it for the first time at the Blomidon Inn this past week, and I loved it. The sterile flowers are the white ones around the edge of the lacecap, and the fertile flowers are blue. The petals are also serrated, and the whole effect is stunning. I don't know where the Lacebys got their plant, but I want one!
The mopheads, as their names suggest, have large, round, moplike clusters of florets. Many of the older varieties bloom on old wood, so if they aren't reliably hardy where you are, you'll find the old stems kill back, and that new growth emerges from the base of the plant and you get no flowers. I tried a 'Nikko Blue' for a few years but finally composted it.
The Cityline series of mopheads may be more to my climate's liking. The plants are more compact, and seem to be hardier, listed at zone 5. So I'm going to try 'Cityline Vienna', a double-flowering mophead with flowers that start out green and turn pink in alkaline soil, blue in acid soil. We'll see what happens.
I do have Endless Summer Original, which is touted for being hardy, blooming on old and new wood, and blooming all summer. Of the five years I've had it, it has performed really well twice, but for the most part it has given me headaches with being unreliable, and I turfed my old plant this spring. I did get another one and planted it in more sun and more steadily moist soil, so we'll see how it does.
The only type of hydrangea I back away from are the oakleaf hydrangeas, which aren't reliably hardy for me. They are soooo beautiful, and may be if global warming is happening, I can find a microclimate where I can try one more time with one of them. If you're not in zone 6 or warmer, I wouldn't bother with the oakleafs, unless you're prepared to baby the plant and have it still not survive.
Perhaps the most jaw-droppingly beautiful are the purple flowered hydrangeas, which are a happy occurence when soil pH is not too acid, not too alkaline, and the original cultivar is a rich deep blue or pink colour. I get some purple blooms on one of my 'Blue Billows' lacecaps, but because I don't have great success with the mopheads, I have yet to have something like the above photo in my garden. I'm content, however, to enjoy them in other people's gardens, and there are a lot of them down around Yarmouth.
I hope this little primer is some help to would-be hydrangea growers, and that you'll be tickled pink, blue, white, or yes, purple with your results!