March 5, 2013

Blackhaws

I want to turn two viburnums that I am growing into trees. They are Viburnum prunifolium, called blackhaw viburnums, and they are naturally multi stemmed, upright, vase shaped shrubs. They can become quite large.

Here is one of the blackhaws, the year after I planted it, still a small and tidy shrub.

With pruning they can be shaped into trees that look similar to hawthorns, with a rigid form, and a lot of character. That's what I want.

However, I haven't got a clue what I am doing.

You can see from last summer's picture that I have already taken off quite a few lower branches.

Viburnum prunifolium is a very densely branched, twiggy shrub and it suckers. The key is to prune it when young, and in the three short years of this viburnum's life in my garden I have taken off over a third of the branches each year. I also cut back the suckers that form around the base.

The branching of blackhaw viburnum can only be described as congested.

This winter I went at it again. That angled crossing branch to the left looked kind of interesting, but to get a vase shaped tree form, I thought it should come off.


Here it is after pruning. I took off the angled stem and I took off another branch on the upper right too.

By taking off the funny branch I may have removed some of the character I wanted, but I do have an idea in mind. Here is what I am going for. This picture is from Learn2Grow:

Or this, from Willow Landscape Design, which says blackhaw is semi evergreen (it's not for me), and that the leaves are purplish (mine have no purple tinge) -- but what a lovely shape and form:

Like all viburnums, blackhaw has pretty white flowers in spring, interesting berries, and decent fall color.  Mine is planted right where I can see it in front of the garden, and although it is still young, it flowered finally last year, with lacy white flat-topped blooms the last week in April.

I have another one that I grew from a six inch seedling planted in 2006. It also needs pruning to become the tree I want it to be.  It is smack up against the house, so it will need to be shaped for size as well.  I know the stubby lower left branch has to come off, but what else should I be doing with this one?

Does the vertical upright branch in the dead center need to be there? Would it look more open and spreading if I took that out?

The good news is that Viburnum prunifolium is so dense that I can't really make a mistake by cutting off the wrong branches. It just grows more, sometimes oddly and in weird directions, but that's the character of this angled, stiff little hawthorn look-alike.

Still, I'd like to influence these to grow into real trees with a nice shape. Suggestions?

28 comments:

  1. That example of the full grown blackhaw is amazing! Tree indeed! Now you have me thinking about the 3 that I have! I'm nut sure if the bottom one needs the center branch taken out. I am no expert but its form is so spectacular! I will be featuring you and your wonderful suggestions for my front yard island bed in a post at the end of this week! Take care and I hope that spring is more near for you...we are expecting 10 inches of snow in the next 24 hours!!!

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    1. Nicole, doesn't that mature blackhaw just amaze? I hope I can get there with mine. I'm looking forward to your design for your front bed -- you won't see your front garden for ages if 10 inches of snow come!

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  2. I am sorry I can't help you. I am one of those people that is afraid of the pruners. Things here get rangy before I start in on them. I can't wait to see what you do. I think what you have done so far looks good.

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    1. Lisa, I am by nature timid with most of what I do in the garden, but I'm trying to get outside the box with pruning. It's hard to make any terrible mistakes, most things recover.

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  3. Hi Laurrie....I think you are doing an awesome job! How wonderful that you grew the second Blackhaw from a little baby. It's doing so well. I would leave the center branch for stability. Making these Blackhaws into trees reminds me of making Crepe Myrtles into trees...I think it's the same principle. Good luck and I can't wait to see how they come out!

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    1. Christy, thanks! You are right about the comparison with crape myrtles, and they can turn into graceful small trees if done right. That's what I want, graceful, angled, and small. Why doesn't nature just grow them that way?

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  4. That's exactly what I think when I'm pruning: "I haven't got a clue what I'm doing"! I have several books on pruning, but getting out there and doing it is always a bit intimidating. Right now I'm trying to limb up a very large rose, and I'm not sure it's going to be a success. Always good to know others feel the same way. Your blackhaw looks great - and almost exactly like your inspiration photos. Great job!

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    1. HolleyGarden, I'm glad you can see my ultimate inspirations taking place in my pruning efforts. Good luck with the rose -- start cutting!

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  5. I also feel unable to offer advice. Looks to me that you are doing a good job. It seems many gardeners feel unsure about pruning and I am no exception. I have three blackhaws but I am growing them into a hedge, which must be easier.

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    1. Jason, a hedge of blackhaw viburnums would make a great screen with their dense branches. And it would be nice in flower.

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  6. Laurrie, from what I can see, you're doing just fine. Keep cutting; as you say, it's difficult to make a mistake you can't fix. Last resort: pollarding.

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    1. Lee, an endorsement from a master pruner is very encouraging! Thanks.

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  7. I'm glad you took off that angled branch, despite losing some of the top shape I'm sure you'll get lots of growth in the coming years that will fill it out. I was recently pruning our apple trees and was thrilled with the knowledge that these are my trees - mine to make mistakes on. These shrubs particularly will continue to grow, it's pretty hard to mess up and if you do it's all yours to fix as you choose.

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    1. Marguerite, a great observation that these are our trees to experiment with. And make mistakes with too!

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  8. Blackhaws so make beautiful trees; the NC Botanical Garden has a Blackhaw that's a lovely small tree.

    I think of pruning as something that you make up as you go along. lol

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    1. Sweetbay, I like that. Pruning is something you make up as you go along. Yep.

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  9. Your first impulse seems to be right. So I'd cut. We have quite a few in the woods around here, but many of them are senescent. I don't see replacements growing from seed, so perhaps the ravenous deer are eating them? Just as they do most of the small trees and shrubs we need to regenerate the forest. (Oops, I'm going off on a deer hate tangent.)

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    1. James, you have hit a chord -- our New England forests are unable to regenerate because deer browse maple and oak and beech saplings every year and have been doing it for decades. No understory growth exists any more.

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  10. I don't think I would cut the leader but I might consider the branch parallel and to the right of the leader from where it branches off further down. I don't always trust my judgment either but you probably won't go too far wrong.

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    1. Patty, thanks, those are my pruning thoughts too. And I can't go too far awry!

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  11. I had a very old blackhaw (40-50 years?), 20 feet in diameter, 20 feet tall, vase shape...It collapsed in a pancake during last year's Halloween freak storm. (Northwest Connecticut) 10 branches flat on the ground in a circle. I'm thinking that the large numbers of horizontal branches brought it down...So your plan to make your blackhaws into vertical trees may give them a better life

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    1. That's too bad about losing the old blackhaw. My little ones did fine in the October snowstorm, their stiff branches didn't bend or break at all. But as they get larger they do become a dense mass of branches and that could spell trouble. I hope my pruning will help!

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  12. I have an 'I Don't Know' viburnum that was left by the builder and is now part of my garden. It might be a v. lennato but, dang, it could be a blackhaw. I've cut mine quite a bit to tame its crazy shape and it looked better each time. I'd take out the main middle stem in the last photo. It feels too vertical.

    But maybe the best thing to do is nothing. Perhaps after it leafs out you'll have a better idea of what to do. Maybe seeing the whole picture will give you a different insight as to how it should be pruned. :o)

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    1. Tammy, viburnums are the mystery plants of the landscape -- when I don't know what a small-leaved shrubby looking plant is, I assume viburnum. I like your cultivar name for them, the 'I Don't Know' variety!

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  13. Laurrie, I see your viburnum looks better after pruning, the branches are separate and there are no crossing of them. I love its shape!

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    1. Nadezda, Thanks. This viburnum is a fast grower, so I will see how my shaping has affected the overall structure this season and next.

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  14. It's difficult to offer advice only having the vantage point of the photo. I'm sure you will come up with the solution that fits your vision. These are lovely shrubs.

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    1. Joene, i will prune and experiment until it looks good and fits my vision --- or I may just adapt my vision to whatever shape I wind up with!

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