Garden School:


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Teaching this week: Assessing a new garden, and when to say "No" !

Wednesday, 25 May 2016

Pruning Curly or Corkscrew Willow

My recent article about attempting to retrieve a past-its-sell-by-date dwarf weeping willow prompted a question from L'enfant bouffante (Hi Rachel! *waves*) about a problem with an over-large Corkscrew Willow.

Rachel - who presumably is a child with a big, 60s-style hairdo, if my O-level French doesn't let me down - asks my advice about whether she can prune a Corkscrew willow that has grown rather too big for its boots.

Now for the good news: Yes! You can!

Right, here's the botany bit: Corkscrew or Curly Willow is properly known as either Salix babylonica or Salix matsudana (experts can't quite agree whether it is one species with two names, or two different but very similar species) and is not a grafted tree, it just grows like that. This means that there is no reversion from rootstock to worry about, no graft union spotting to do, and as it is a willow, you can prune it with confidence: It Will Grow Back.

 For anyone who hasn't seen one of these lovely trees, here's one I grew from a cutting earlier (left). Obviously, this is a small one.

They are more or less upright in habit, they can get to 30' tall if you let them, and all the branches are wavy, as are the leaves: but unlike Corkscrew or Contorted Hazel, the leaves are merely pleasantly wavy, not hideously malformed and diseased-looking. Not that I'm biaised, you understand, and I do have a purple-leaved Contorted Hazel of my own, which I love: but I really don't like the normal green ones. Well, to be honest, I think they're fabulous in winter, when you can see the skeleton of them, but in summer, frankly, I think those leaves just look diseased. So there.

Right, where were we? Oh, yes, Corkscrew Willow.

Not grafted, upright habit, and it grows nearly as fast as many "normal" willows, and yes, they can easily get too big for their situation.

The good news is that you can chop it as much as you like, and it will probably not mind in the slightest. Bearing in mind that I haven't seen it, I would suggest that if it is close to your house and/or overhanging next door, get a tree surgeon in to do the actual chopping: they will reduce it safely, they'll take away the waste, and they will/should leave you with a shapely, well balanced tree, which will, once it regrows, quickly become beautiful again.

Having said that one advantage of tree surgeons is that they take the waste away, bear in mind that long wavy stems are very much in demand by flower arrangers, so if you know anyone who does this, or have a college with a floristry course nearby, it's worth asking them if they would be interested in collecting the offcuts. Or, trim up a pile of the longest stems you can retrieve on the day,  put them in the garage to dry out slowly,  then sell them! A little gold or glitter spray, bung them in a tall vase and hey presto! instant Christmas decoration. Did I really just say "christmas?" In May? Oh dear.

As well as hopefully recycling some of the branches,  my personal advice is to take cuttings from it before the work is done: chop off a few branches of about pencil thickness, and either pot them up, or push them into the ground, water well, and leave them  to grow:  this time next year, they should be rooted, so you can either sell them, or hold them in reserve in case the big tree does not regrow the way you would like it to.

I should also say that you have several options regarding the style of cutting, which your tree surgeon should discuss with you. You can have it:

1)  crown-lifted and thinned, which means they will reduce the overall height and density, but you will still have a tree:

2) they can "hat-rack" it, also known as "topping" which means they cut off all the main branches at the same distance from the trunk, leaving a hideous truncated skeleton which then sprouts a bushy lollipop of foliage at each tip (not recommended);

3) they can pollard it, which means they chop off every large branch, leaving you with a tall bare stump: it will quickly regrow, it's perfectly acceptable, and this is how street trees are normally treated - but once you start pollarding you will have to have it done regularly for ever more.

4) they can coppice it - like pollarding but at knee height, making it very, very easy to do future maintanance on it.

Those last two are not normally done on ornamental trees, but if they advise that pollarding/coppicing is the best thing for the tree, then so be it. It WILL regrow!

10 comments:

  1. Rachel, this is marvellous, and I feel slightly giddy to see your response in print. Thank you. I am struggling to get any sort of decent picture to show you, because who uses proper cameras any more, and my phone can't quite get the height all in. Safe to say, Curly is beautiful, but a bit of beast. I am glad it doesn't seem necessary to remove it entirely. Looked around and there seems to be some good, properly qualified surgeons not too far away who have some good pictures of trees they have thinned, and I will go for it. Thanks again, and yes, my hair is, at times as unwieldy as the tree. More akin to Crystal Tipps or a Douglas Fir than Corkscrew Willow, but you can't have everything.

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  2. ("hair like Crystal Tipps..." *cries with laughter*)

    Rachel, you are most welcome, and I hope you end up with something that is smaller, safer, more neighbour-friendly, but still beautiful!

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  3. Thanks for this article!
    Just found out the monster at the end of the garden is a Corkscrew willow. It looks like it's been pollarded before but has regrown back to about 30ft high again, so will see if it can be crownlifted and thinned. Is it best for this to be done in the winter?

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    1. Hi Carl, apologies for the delay in responding, I have only just found a whole mass of comments waiting for moderation!

      So,your pollarded corkscrew willow: yes, it will have regrown to a good height, they are very resilient!

      You can either crownlift and thin, or you can simply re-pollard it, whichever you prefer. As for when, it is traditional to do this work at the very end of the year, from late autumn through to early spring, mostly so that you can see what you are doing, once the leaves are out of the way.

      But, willow being willow, you can cut it at pretty much any time of year without damaging it.

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  4. Hi Rachel,I have about 6 curly willow "stems" growing together in a pot; they are about 2 years old.Although I like the effect,I am wondering,having read your previous comments,if I should separate them, if they are not too closely
    intertwined. The silver Fox

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    1. Hi Silver, (so tempting to start HiHo.... resist.... resist...)
      Interesting question, impossible to answer without a photo of the pot in question, but as a general answer I would say that if you like the effect, then stick with it!

      After 2 years of growing together, their roots will probably be quite intermingled by now, so trying to seperate them might result in damage to all of them. So I'd suggest leaving them to grow in their pot - make sure it's up off the ground so they can't root through the drainage holes - and if, over time, you find it's getting a bit too congested, just prune out some of the lower branches to reveal the original 6 stems.

      Hope this helps!

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  5. Hi Rachel, I have a corkscrew willow, its around 15/20 years old, this year I have noticed what look like black clumps growing down from some of the fine branches. What could these be, on examination they are dark green in colour. Any idea?

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    1. Hi there, I have no idea! Perhaps you could send me some photos of these clumps - email address at the top of the page, on the right - and then I could have a look for you?

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  6. Have a 13 y/o Salix that has become quite large and is truncated...I have had it trimmed but the trim sites just keep growing new branches. Is there any technique that can be done to prevent the cut sites from growing new shoots..like putting something like tar or whatever they do to other trees at the cut site...I have unfortunately been one of those overeager gardeners who got the original twig in a flower bouquet and now I have a monster 10 feet from my homes foundation...Should i have the whole tree removed and save the house???

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    1. Hi there: an interesting question!

      Covering the cuts with some sort of sealant is no longer done: it used to be thought that it "sealed" the wound, but current thinking suggests that doing so might "seal in" bacteria etc, leading to rotting. So on balance, it's best to leave wounds to heal by themselves.

      However, as you are finding, willows are full of life, and every cut seems to sprout a handful of new shoots!

      To prevent the cut sites growing new shoots, you would need to keep rubbing out the new buds as soon as they appear, which means constant vigilance - checking it every couple of days in spring, and at least once a week through the summer.

      When I say "rubbing out the buds" that's exactly what I mean: as soon as you see a tiny nub, rub it off with your hands. Don't cut it off, or it will just grow back, possibly with twice as many shoots.This only works if you catch the buds when they are tiny.

      And it doesn't work at all if the cuts are way above head height, because you won't be able to reach them!

      As for the problem of "trees too close to the house", it is always best to take professional advice on that one, so call a tree surgeon and see what they say.

      Oh, and don't forget that you can always use some of the cut branches to start a new tree, possibly a bit further away from the house...

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