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Colourful oakleaf hydrangeas worth the risk

Hydrangea leaves (Photo by Brendan Zwelling)

I seem to be increasingly tolerant of risk these days, especially when it involves a desirable shrub, and oakleaf hydrangeas (Hydrangea quercifolia, Zone 6) fall into this category. They’re borderline hardy in my Zone 6a garden, meaning this is the coldest winter temperature they can survive in. Like all hydrangeas, H. quercifoliarequires consistent moisture, and suffers in drought and dry soil. Any plant growing at the edge of its hardiness zone is challenged by winter cold, and combine that with my inadequate irrigation practices, the end result was predictable — my oakleaf hydrangeas didn’t bloom this year.

I grow ‘Pee Wee’ hydrangea (H. quercifolia ‘Pee Wee’, 40 x 40 inches/1 x 1 m, Zone 6), a dwarf woodland hydrangea with five-inch (13-cm) flower panicles and more refined foliage than the full-size shrubs. It makes a lovely corner shrub on a driveway border, under the weeping branches of a ‘Red Jade’ crabapple (Malus ‘Red Jade, 16 x 16 feet/5 x 5 m, Zone 4). The standard species of H. quercifolia (4 x 4 feet/1.2 x 1.2 m, Zone 6) is a good size for a shrub border; if you have the room, it looks dramatic in a triangle of three planted together. The full-size hybrid ‘Alice’ (H. quercifolia ‘Alice’, 8 x 8 feet/2.5 x 2.5 m, Zone 6) is larger and can be used as a specimen lawn shrub in a big garden. Flower sizes increase with shrub sizes, and some of the big hybrids have panicles 10 to 14 inches (25 to 36 cm) long.

So, what’s the value of a hydrangea that’s an unreliable bloomer in my garden? Well, oakleaf hydrangeas have interesting foliage, quite like enlarged oak leaves in shape, and with a thick texture. What’s more, when grown in half-day sun or more, the leaves take on a palette of rose to burgundy hues in the autumn, holding onto the shrub for several weeks as the colours deepen. The leaves won’t colour up as well when grown in full shade, but the plant produces large creamy flowers turning to pink and has enough character to be notable all summer. In the past, the flowers on ‘Pee Wee’ have been charming, and this is the only year they failed to appear. Despite the generally warm winter last year, there might have been a day or two in early spring when the buds were nipped by frost. But I’m keeping the faith with this plant, because it has such good character.

The cleanup continues

It’s mid-November, and I’m miles behind in cleaning up the garden. I try to do as much as possible now, because spring comes on so quickly and I want to be out rattling the doors at plant nurseries. But the more plants I grow, the more end-of-season chores there are. I look at the garden, hear the clock ticking—and don’t know where to begin.

This scenario requires a high degree of organization if I’m to effectively clear the beds of seasonal debris. I begin by dividing the garden into areas, starting close to the house and moving toward the perimeters. My back garden is large and divides into six areas, each with its list of basic autumn maintenance and special problems to be addressed. I work from start to finish in one area at a time, and follow a hierarchy of tools. I begin with the smallest tool—my secateurs—and accomplish everything that tool is capable of: cutting down perennial stalks, trimming back evergreens, removing dead twigs from deciduous shrubs. Then I work with the next largest tool—my loppers—thinning out canes from overgrown euonymus and dogwood shrubs, cutting back ‘Annabelle’ hydrangeas and blue Arctic willow (Salix purpurea ‘Nana’, 4 x 5 feet/1.2 x 1.5 cm, Zone 5) to 10 inches (25 cm), and pruning up the lowest growth of tree branches overhanging planting beds. (There’s always quite a lot of this to be done with the ‘Red Jade’ weeping crabapple.) I move on to work with a pruning saw, cutting outward-leaning branches from small trees like Japanese maples to keep them shapely, clearing dead wood from hemlock interiors, and removing the occasional large branch from major trees like river birch and fern-leaf beech (Fagus sylvatica ‘Asplenifolia’, 39 x 26 feet/12 m x 8 m, Zone 5). Finally, I use a spade to dig out seedling ash and redbud trees that pop up everywhere.

Dividing the work into areas and tool categories helps to focus my efforts, and insures I can always find where I’ve left off. And if I don’t get it all done, at least in spring I can point to areas that are completely finished, while I continue to catch up with what’s left over from 2010. Really, it’s a merry-go-round of activity and I’m trying to organize my way through it.

Gifts for gardeners

It’s nearly holiday season and whatever your celebration — Chanukah Dec. 1 to 9, Christmas Dec. 25, Kwanzaa Dec. 26 to Jan. 1 — gardeners need gifts! For an actively engaged gardener, you might like to consider one of the oversized kneeling mats to cushion knees, keep lower pant legs dry, and double as a seat cushion on cold stone steps. Lee Valley (leevalleytools.com) has an extra large seat and kneeling pad made of one-inch (2.5-cm) thick polyethylene, 13 1/2 x 14 1/2 inches (34 x 37 cm), for $8.50. Rittenhouse (rittenhouse.ca) offers two jumbo kneeling pads made of soft waterproof canvas and polyethylene: 18 x 24 inches (45 x 60 cm), standard thickness, $22.94; and ¾-inch (2 cm) thickness, $27.99. These are practical gifts that would be used and appreciated.

Still blooming in my garden: ‘Morning Light’

My favourite ornamental maiden grass, variegated green and cream Miscanthus sinensis ‘Morning Light’ (4 x 4 feet/1.2 x 1.2 m, Zone 6) is finally opening its pink flower tassels. I don’t have enough sun in my garden to bring the tassels on any earlier, and most years they fail to open. But this year, perhaps encouraged by the hot summer, I can see them moving in the wind. I love this graceful, shimmery plant with tassels or not, but it’s fun to see what ‘Morning Light’ is capable of with a bit of heat in an extended season.

That’s it for this week—always a pleasure having you visit me at Garden Making.

6 thoughts on “Colourful oakleaf hydrangeas worth the risk”

  1. To Shirley, Nov.19

    Your climbing hydrangea (Hydrangea anomala subsp. petiolaris, Zone 5) is a gorgeous thing — I have two of them myself. It's also a large and heavy vine (potentially running 60 to 80 feet), that carries considerable weight from the horizontally extending branches, and becomes even heavier when the branches are laden with snow. And yes, it can easily pull down your fence. Climbing hydrangea can be pruned now, it won't mind at all, so please save your fence. (You might need a pruning saw for the central, heavy wood.) Once you cut it back, you'll need to keep an eye on it every summer. My experience is that this vine is a slow starter (taking two to three growing seasons to establish a roothold in the ground), then assumes more vigor with every passing year. The old ones are the fastest! But it's a true four-season beauty (attractive form, scented flowers, exfoliating bark), and a valuable plant—so count yourself lucky, though be watchful about reining it in each year.

    Reply
  2. I have a 30 year old climbing hydrangia, the one with the flat white flower.

    I have done some pruning of this vine in the summer and spring, but I now need to know if it is too late to trim in back a bit now. After the leaves have come off, I noticed that it is pulling over my fence with its weight.

    Could you advise me if I can still do some pruning of the vine. I also would like to say how much I have been enjoying your magazine. I have cancelled subscriptions to all others.

    Reply
  3. To Joy, Nov. 18

    Perhaps you can try to locate the Hydrangea quercifolia again next spring? (I notice all three hydrangeas mentioned in the blog are available at hortico.com.) You're just outside the plant's Zone 6 hardiness zone, but in a sheltered location it might work. If you try to grow this plant in your cold garden, I would heap a lot of leaves on it in late autumn. Good luck.

    Reply
  4. I also would love to have this hydrangea .. in fact I ordered it one year from a mail order nursery and they had crop failure so I didn't get it .. but I keep thinking of it every year and wondering .. i am in zone 5b Kingston ON ..

    On "Morning Light" .. I planted two of them this year and bloom or not? I love them so much .. they are one of the most beautiful of the grasses I have .. but if they eventually want to bloom for me ? I say bring it on ! haha

    Joy

    Reply
  5. Zone 4b now 5! Oh, I admire your bravery. Just in case you might be interested in a late-blooming hydrangea (but alas, without notable autumn foliage) — H. paniculata 'Tardiva' (about 7 feet X 40 inches 2 x 1 m, Zone 4, sun to part shade). It's a tall plant with six-inch (15-cm) flowers starting in September. You could have colourful foliage from H. quercifolia, and nice flowers from H. paniculata 'Tardiva' at the same time. The best of both worlds!

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  6. Glad to hear people in higher zones than mine also have trouble blooming Oakleaf. In the 6 years I've had bloom once but oh my that autumn foliage makes up for it every time.Ann Boyd Zone 4B now 5

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