Pruning to make bushier

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bamboo_bob
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Pruning to make bushier

Post by bamboo_bob »

I have some bamboo I planted as a privacy hedge. I believe the species is P. Rubromarginata. It has filled in nicely over the past 3 years and is now about 25-30 feet tall. The issue is it seems as though the foliage is now migrating towards the top of the canopy and thinning out on the bottom, which defeats the purpose of my privacy hedge. So I was thinking of cutting 5-10 feet off the tops to let more light in and to encourage more foliage growth down low. So I have two questions. Does this sound like it's going to work? And is now a good time to do it? Some of the new shoots are still putting out their leaves, so I'm not sure if I want to touch those yet. But I'm thinking doing it in summer for the mature ones will give it plenty of time for growing new leaves while it's still getting a lot of daylight.
Tarzanus
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Re: Pruning to make bushier

Post by Tarzanus »

Current shoots and culms will most likely remain without low branches, but if you cut off the top of emerging shoots next year, new growth should appear much lower.
Some Phyllostachys bamboos tend to grow branches low and some can't wait to push the canopy further up and show their culms. By picking the right variety, you can make it much easier to keep it bushy.
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needmore
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Re: Pruning to make bushier

Post by needmore »

Some species react more than others, not sure about Phy rubromarginata but I think that shortening the culms height and branch length should result in the plant making more leaves where there are leaf buds but of course, no new branches will emerge lower than current so it should get bushier where there is already foliage. I'd try the prior year culms anytime, new ones wait a bit.
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bamboo_bob
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Re: Pruning to make bushier

Post by bamboo_bob »

Thanks. There’s a lot of branches below but few have leaves. I guess they all fell off after the light disappeared. Maybe they’ll grow some new ones after pruning. I’ve read cutting the thick culms as soon as they come up can also help control height.


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Tarzanus
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Re: Pruning to make bushier

Post by Tarzanus »

When culms are leafed out completely, they won't grow new branches below. You need to severe them as they grow and even then, some bamboo species just refuse to grow branches all the way down. In dense groves where there's little or no light, first branches start almost at the top. I wouldn't cut the fully developed culms. In worst case, you will need to think about changing the bamboo variety or add another one which reacts to pruning.
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needmore
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Re: Pruning to make bushier

Post by needmore »

Tarzanus, I'm not sure I follow what you are saying - no new branches will sprout but leaves will on some species. I've intentionally caused dormant leaf buds on existing lower branches with existing branchlets to fire some of those buds in reaction to a loss of foliage elsewhere on the culm. Atrovagiata, B ventricosa, S tootsik all do this for me, in fact I'm pruned some ventricosa culms yesterday to maintain a leafy rounded bush look. When I did this to Atrovaginata it looked pom pom 'ish and was interesting. Never tried Rubromarginata though, it might do squat.
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bamboo_bob
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Re: Pruning to make bushier

Post by bamboo_bob »

I know these can look bushy because I have another grove on the other side of the property I planted one year later than the one in question and just this shooting season it filled in solid, leaves right to the ground. I expect next season it will send up the bigger ones and progressively start moving leaf to the top. So my plan with that is to cut the big ones as they come up and actively try to control the height so it doesn’t become 30 feet in the first place.


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Tarzanus
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Re: Pruning to make bushier

Post by Tarzanus »

Bambusa has dormant buds, all tropical seem to have them. Fargesia and Borinda as well. Phyllostachys on the other hand is a bit different and it sometimes lacks that growing bud or it aborts during the shooting. In that case, there's no starting point for a branch to start later on, even if pruned. If it does have living branches, but the leaves are scarce, pruning should result in more leaves, those have enough viable buds.
If I compare Phyllostachys aurea with Phy. aureosulcata for example, the first offers way more options for pruning, because first couple of buds usually remain dormant and can be revived, with auresulcata bamboo, those buds are not present or not viable. Same thing with my Shiroshima. If I cut it to a certain height during the shooting, they branch out and I can get a thick fence that looks great. If I let them branch out first and then do the cutting, lower buds sometimes fail and the whole thing looks far worse.
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needmore
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Re: Pruning to make bushier

Post by needmore »

Got it, yes, what I've seen matches that, existing branchlets can fire dormant leaf buds but as you say dormant branch buds not so much.
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Diane
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Re: Pruning to make bushier

Post by Diane »

Hi there
This is a random question, but I also have Phy Rubromaginata bamboo (just planted in June) and would love to see a photo of what yours looks like 3 years old.
If you have a chance to upload photos I’d love that.
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