Should I Prune My Dappled Willow in the Fall?

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The dappled willow is very popular, but when and how do you prune it? Source: springmeadownursery.com

Question: I planted a dappled willow in my garden this summer. Should I prune it in the fall? And does it need any kind of winter protection?

Lili

Answer: First, the dappled willow (Salix integra ‘Hakuro-nishiki’*) is a shrub that is also known as variegated willow, flamingo willow or dappled Japanese willow. It’s grown for its narrow leaves mottled white and pink in the spring. As the spring progresses, the pink fades away, leaving a white and green color, then the white disappears too, giving entirely green leaves by the end of the summer. There is no noticeable fall leaf coloration, but younger branches take on a reddish tinge that offers some winter appeal.

*S. integra ‘Flamingo’ is also widely sold and is claimed to be an improved version of ‘Hakuro-nishiki’ with a better pink coloration in the spring. I must admit I can’t see any difference and the Royal Horicultural Society seems to agree with me, as they list S. integra ‘Nishiki Flamingo’ as a synonym.

To Prune or Not to Prune?

“Should I prune it in the fall?”

In my opinion, you didn’t ask the right question. The question should be “do I have to prune it… ever?”, because one of the laidback gardener’s main principles is that you never prune plants just because they’re there. You have to have a good reason to do so.

And gardeners usually have two reasons for wanting to prune their dappled willow.

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When allowed to grow normally, the dappled will is quite a large shrub. Source: tellurianflora.wordpress.com

First, it is commonly pruned to keep it dense and compact. Indeed, the dappled willow is actually a large shrub with a somewhat arching branches that can grow to about 12 feet (3.5 m) in height and 8 feet (2.5 m) or more in diameter if it’s never pruned. Personally, I like it that way and never prune mine. My specimen is now about 8 feet (2.5 m) in height and 5 feet (1.5 m) in diameter after 18 years, which I consider quite acceptable. Of course, I planted it taking into account its future size, in the company of other large shrubs in a spot where access for pruning would be difficult anyway. I like that fact that it requires no pruning whatsoever under my conditions.

Late Winter/Early Spring Pruning

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Severely cut back in earliest spring, this dappled willow will produce a modestly sized shrub over the summer. Source: www.obsessiveneuroticgardener.com

But I’m an exception to the rule. Most people prune their dappled willow severely each year, down to about at 6 to 12 inches (15 to 30 cm) from the ground. This results in a modestly sized, rather rounded shrub about 5 feet (1.5 m) in height and diameter.

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The rather insignificant flowers of the dappled willow at least tell you it’s time to prune … if you’re into that sort of thing! Source: http://www.willowsvermont.com

And fall is not the usual pruning season. Rather, it is generally pruned in late winter or early spring, at snow melt or, in warmer regions where there is no snow, around the same time as the shrub blooms, which it does quite discretely, with rather small catkins.

As a laidback gardener, I find forcing plants to take on an unnatural shape time-consuming and unnatural. If I want a shrub 5 feet (1.5 m) tall and wide, I’ll put in a modestly sized shrub that naturally matures at 5 feet (1.5 m) in height and diameter and stays there (there are so many of them!), not a big shrub I’ll need to cut back every year.

A Mid-Summer Trim

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A midsummer pruning will bring back the pink and white variegation … for a short time. Source: Salicyna, Wikimedia Commons

That’s pruning number 1, but a lot of gardeners, much harder working than myself, give the shrub a second trim in mid-summer (July or early August) too, when its foliage has lost much of its variegation. This is just a quick trim, shortening all the branches by about 6 inches (15 cm). This quickly stimulates dense regrowth just as variegated pink and white as it was in the spring, although the color is not as long lasting. (The pink, especially, fades quickly under the effect of the summer heat.) Trimming a dappled willow in this way gives you something that looks like a shrub with a poodle cut.  Not exactly what I want in my haphazard garden, with its “back to nature” theme!

Lollipop Willows

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Dappled willows grafted onto an upright trunk.  Source: 23mega.by

The dappled willow is often sold grafted onto a straight trunk (this is called top-grafted or standard form) in order to form a small tree, looking rather like a lollipop at the time of purchase. Does this change anything in how you prune it?

Not really: it’s the same shrub, except now lifted off the ground as if on stilts, and will need essentially the same care. So prune it once a year, twice a year or not at all: it’s your choice.

Basic Dappled Willow Care

The dappled willow is a pretty easy plant to grow, doing fine in most garden conditions.

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The reddish branches in winter, here on a heavily pruned (pollarded) top-grafted specimen. Source: www.louistheplantgeek.com

It prefers full sun or, in a pinch, partial shade, in soil of just about any quality, well-drained, but still, always a bit moist. You may need to water several times the first year until it settles in. Like most shrubs, it will prefer a good mulch to keep its root zone cool and moist. Note too that, unlike large willows (some are huge trees!), its root system is not invasive.

Although some sources claim the dappled willow is to hardy to only zone 5, the species (S. integra) is native to cold northern regions of Eastern Asia, from Japan to northern China and even Siberia and is perfectly hardy in zone 3b. The cultivar seems just as hardy as the species.

Beware of fertilizers rich in nitrogen with this plant: they stimulate meteoric growth … but the beautiful pink and white colors are lost. Use instead a slow-release organic fertilizer where the first of the three numbers (nitrogen) is less than 8. Moreover, it’s not a needy shrub and won’t require a lot of fertilizer: a single fertilizer application of slow release every three or four years will probably be plenty.

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Cute as they may be, tree-form dappled willows are, like most top-grafted plants, not always very long-lived. Source: www.limecross.co.uk

Finally, when buy a standard (tree-form) dappled willow (i.e. a lollipop), remember that it’s actually two plants in one: a dappled willow grafted on top of a trunk-forming willow* with green leaves. Any branches that appear from the base of the plant or from below the graft point will be from from the rootstock, not dappled willow, and will not bear variegated leaves, but entirely green ones. You’ll have to prune off these reversions to maintain both the lollipop look and the variegated coloration.

*Although S. integra itself is very hardy, top-grafted forms (lollipops) are often grafted onto a less hardy rootstock. If you live in a cold climate, make sure the rootstock is at least as hardy as the top-graft!!

The dappled willow: striking whether you prune it or not… and may I suggest the latter!

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Small Trees for Small Spaces

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20170418A Daderot, WC

Kelly’s Gold box elder (Acer negundo ‘Kelly’s Gold’) is an example of a tree small enough for an urban lot. Photo: Daderot, Wikimedia Commons

Not every gardener has enough space for a large tree on their property. A full-grown oak, for example, can measure 75 tall and 75 feet wide: that’s enough to cover the average front yard!

And space is only one consideration. There are all sorts of other reasons for preferring a smaller tree: there may be electric wires you want to avoid, a view you’d like to preserve, or maybe a swimming pool where you want full sun. Whatever the reason, if you’re looking for a smaller tree, look no further. The following list will give you a lot of choices.

  1. Acer negundo ‘Flamingo’ (‘Flamingo’ box elder) H: 25 ft (8 m), D: 20 ft (6 m), Z6
  2. Acer negundo ‘Kelly’s Gold’ ( ‘Kelly’s Gold’ box elder) H: 20 ft (6 m), D: 12 ft (4 m), Z4b
  3. Acer palmatum (Japanese maple) H: 4-25 ft (1.2-8 m), D: 4-25 ft (1.2-8 m), Z6
  4. Acer pensylvanicum (snakebark maple) H: 15-22 ft (5-7 m), D: 15 ft (5 m) Z4a
  5. Acer spicatum (mountain maple) H: 20 ft (6 m), D: 12 ft (4 m) Z2
  6. Acer tataricum ginnala (Amur maple) H: 20 ft (6 m), D: 20 ft (6 m), Z2b
  7. Aesculus pavia (red buckeye) H: 10-20 ft (3-6 m), D: 10-20 ft (3-6 m), Z5
  8. Alnus glutinosa ‘Imperialis’ (cut-leaved alder) H: 25 ft (8 m), D: 12 ft (4 m), Z4b
  9. Amelanchier arborea (downy serviceberry) H: 22 ft (7 m), D: 12 ft (4 m), Z4a
  10. Aralia elata (Japanese angelica-tree) H: 20 ft (6 m), D: 20 ft (6 m Z4b
  11. Betula nigra ‘Little King’ (Fox Valley™ river beech) H: 10 ft (3 m), D: 10 ft (3 m), Z4b
  12. Caragana arborescens (Siberian peashrub) H: 12-22 ft (4-7 m), D: 12-20 ft (4-6 m), Z2

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    American hornbeam (Carpinus carolinana). Photo: Daderot, Wikimedia Commons

  13. Carpinus caroliniana (American hornbean) H: 25 ft (8 m), D: 22 ft (7 m), Z3b
  14. Cercis canadensis (eastern redbud) H: 15-20 ft (5-6 m), D: 15-20 ft (5-6 m), Z6
  15. Chionanthus virginicus (white fringetree) H: 12-20 ft (4-6 m), D: 12-20 ft (4-6 m), Z5b
  16. Cornus alternifolia (pagoda dogwood) H: 15-25 ft (5-8 m), D: 15 ft (5 m), Z3b
  17. Cornus alternifolia Golden Shadows™ (Golden Shadows pagoda dogwood) H: 15-25 ft (5-8 m), D: 15 ft (5 m), Z3b
  18. Cornus florida (flowering dogwood) H: 15-30 ft (5-9 m), D: 15-30 ft (5-9 m), Z6
  19. Cornus kousa (kousa dogwood) H: 15-30 ft (5-9 m), D: 15-30 ft (5-9 m), Z6
  20. Cotinus obovatus (American smoketree) H: 15-25 ft (5-8 m), D: 15-25 ft (5-8 m), Z4b
  21. Crataegus spp. (hawthorn) H: 15-30 ft (5-10 m), D: 10-30 ft (3-10 m), Z:variable, 2b-5
  22. Elaeagnus angustifolia (Russian olive) H: 25 ft (8 m), D: 25 ft (8 m), Z2b
  23. Hamamelis virginiana (common witch hazel) H: 15-22 ft (5-7 m), D: 15-22 (5-7 m), Z4
  24. Heptacodium miconoides (seven sons flower) H: 12-15 ft (4-5 m), D: 10 ft (3 m), Z4b
  25. Maackia amurensis (Amur maackia) H: 22-30 ft (7-9 m), D: 20-25 ft (6-8 m), Zone 3b

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    Loebner magnolia (Magnolia loebneri). Photo: Jean-Pol GRANDMONT, Wikimedia Commons

  26. Magnolia x loebneri (Loebner magnolia) H: 25 ft (8 m), D: 15 ft (5 m), Z4b
  27. Malus spp. (crabapple), H: 10-25 ft (3-8 m), D: 8-22 ft (2.5-7 m), Z4
  28. Prunus cerasifera ‘Newport’ (Newport purple leaf plum) H: 15 ft (5 m), D: 15 ft (5 m), Z5
  29. Prunus maackii (Manchurian cherry) H: 22 ft (7 m), D: 15 ft (5 m), Z2b
  30. Prunus serrulata ‘Kwanzan’ (flowering cherry) H: 22 ft (7 m), D: 15 ft (5 m), Z6
  31. Prunus virginiana (chokecherry) H: 15 ft (5 m), D: 12 ft (4 m), Z2b
  32. Pyrus calleryana ‘Chanticleer’ (‘Chanticleer’ callery pear) H: 25-30 ft (8-10 m), D: 12-15 ft (4-5 m), Z6
  33. Salix discolor (American pussywillow) H: 15 ft (5 m), D: 6-12 ft (2-4 m), Z2a
  34. Sorbus decora (northern mountainash), H: 25 ft (8 m), D: 15 ft (5 m), Z2
  35. Sorbus x intermedia (Swedish whitebeam) H: 20 ft (6 m), D: 12 ft (4 m), Z4
  36. Syringa reticulata (Japanese lilac) H: 25 ft (8 m), D: 25 ft (6 m), Z2a
  37. Syringa reticulata pekinensis ‘Zhang Zhiming’ (‘Beijing Gold’ Peking lilac) H: 25 ft (8 m), D: 8 ft (78 m), Z2a

Shrubs Turned Into Trees

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This dappled willow (Salix integra ‘Hakuro Nishiki’) is not only grafted onto an upright trunk, but requires considerable pruning to maintain its rounded form. Photo: Wouter Hagens, Wikimedia Commons

The following “trees” are not really trees. They are instead shrubs either grafted at the top of an upright stem or pruned to resemble a tree. They are usually quite expensive (there’s a lot of work involved in creating them) and often short-lived, plus many of them sucker from the roots or need regular pruning, but this is also the group in which you find some truly miniature trees suitable for even the smallest yard or even for growing in a pot on a deck or balcony.

It’s up to you to decide whether their benefits outweigh their disadvantages!

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Weeping birch (Betula pendula ‘Youngii’). Photo: Mat86, Wikimedia Commons

  1. Betula pendula ‘Youngii’ (weeping birch) H: 22 ft (7 m), D: 30 ft (9 m), Z2b
  2. Caragana arborescens ‘Pendula’ et ‘Walker’s’ (weeping Siberian peashrub), H: 6 ft (2 m), D: 3 ft (1 m), Z2
  3. Catalpa bignonioides ‘Nana’ (umbrella catalpa) H: 15 ft (5 m), D: 15 ft (5 m), Z5b
  4. Cotoneaster apiculatus (cranberry cotoneaster) H: 3 ft (1 m), D: 3 ft (1 m), Z5b
  5. Euonymus alata ‘Compacta’ (dwarf burning bush) H: 6-10 ft (2-3 m), D: 6-10 ft (2-3 m), Z4b
  6. Euonymus fortunei (wintercreeper) H: 3-5 ft (1-1.5 m), D: 2.5-3 ft (0,75-1 m), Z6b
  7. Ginkgo biloba ‘Mariken’ (dwarf ginkgo) H: 6 ft (2 m), D: 2.5-3 ft (0,75-1 m), Z3
  8. Ginkgo biloba ‘Pendula’ (weeping ginkgo) H: 25 ft (8 m), D: 12 ft (4 m), Z3
  9. Gleditsia triacanthos ‘Emerald Kascade’ (‘Emerald Kascade’ weeping honeylocust) H: 15-25 ft (5-8 m), D: 15-25 ft (5-8 m), Z5b
  10. Halimodendron halodendron (salt tree) H: 6-10 ft (2-3 m), D: 3-6 ft (1-2 m), Z3
  11. Hydrangea paniculata (panicle hydrangea) H: 6-8 ft (2-2.5 m), D: 5-8 ft (1.5-2.5 m), one 3
  12. Juniperus horizontalis ‘Wiltonii’ (‘Wiltonii’ weeping juniper) H: 3-6 ft (1-2 m), D:3-4 ft (1-1.20 m), Z2
  13. Juniperus squamata ‘Blue Star’ (‘Blue Star’ singleseed juniper) H: 3 ft (1 m), D: 2.5 ft (0,75 m), Z5b

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    Umbrella catalpa (Catalpa bignonoides ‘Nana’)

  14. Larix decidua ‘Pendula’ (weeping larch) H: 3-10 ft (1 à 3 m), D: 3-ft (1 à 2 m), Z3b
  15. Malus sargentii ‘Tina’ (‘Tina’ Sargent crabapple) H: 3-6 ft (1-2 m), D: 3-6 ft (1-2 m), Z4
  16. Magnolia stellata (star magnolia) H: 5-9 ft (1.5-2.5 m), D: 5-12 ft (2.5-4 m), Z4b
  17. Morus alba ‘Pendula’ (weeping white mulberry) H: 6-12 ft (2-4 m), D: 12-25 ft (4-8 m), Z4
  18. Picea pungens glauca ‘Globosa’ (globe blue spruce) H: 3-6 ft (1-2 m), D: 3 ft (1 m), Z4
  19. Prunus triloba ‘Multiplex’ (flowering almond) H: 3-6 ft (1-2 m), D: 7-10 ft (2-3 m), Z3
  20. Prunus x cistena (purple-leaf sand cherry) H: 5-12 ft (1.5-3.5 m), D: 3-6 ft (1-2 m), Z3
  21. Pyrus salicifolia ‘Pendula’ (weeping willowleaf pear) H: 15-30 ft (5-10 m), D: 15-30 ft (5-10 m), Z4b
  22. Physocarpus opulifolius ‘Monlo’ (Diabolo™ ninebark) H: 3-8 ft (1-2.5 m), D: 4 ft (1.2 m), Z3
  23. Robinia pseudacacia ‘Lace Lady’ (Twisty Baby™ black locust) H: 15 ft (5 m), D: 15 ft (5 m), Z4b
  24. Robinia pseudoacacia ‘Umbraculifera’ (umbrella black locust), H: 22-30 ft (7-10 m), D: 20 ft (6 m), Z4b
  25. Rosa x (hybrid tea tree rose), H: 3 ft (1 m), D: 1.5 ft (0.5 m), Z7 ou 8
  26. Rosa x (hardy shrub tree rose), H: 3-6 ft (1-2 m), D: 3 ft (1 m), Z4

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    Kilmarnock weeping willow (Salix caprea ‘Kilmarnock’)

  27. Salix caprea ‘Kilmarnock’ (‘Pendula’) (‘Kilmarnock’ weeping willow) H: 1.2-10 ft (1.2-3 m), D: 3-6 ft (1-2 m), Z4b
  28. Salix integra ‘Hakuro-nishiki’ (dappled willow) H: 5-15 ft (1.5-5 m), D: 5-15 ft (1.5-5 m), Z4b
  29. Syringa meyeri ‘Palibin’ (‘Paliban’ Korean lilac) H: 6 ft (2 m), D: 6 ft (2 m), Z3
  30. Syringa patula ‘Miss Kim’ (‘Miss Kim’ Manchurian lilac), H: 6 ft (2 m), D: 5 ft (1.5 m), Z3
  31. Ulmus glabra ‘Camperdownii’ (‘Pendula’) (Camperdown elm) H: 10 ft (3 m), D: 10 ft (3 m), Z4b20170418A Daderot, WC