When do you trim old culms?

[da7id]

Hi, I’m a bit of a newbie here. I’ve got a bunch of different types of bunching bamboo growing in Austin, TX -Bambusa, Dendocalamus & Gigantochloa. I’m wondering when is the best time to chop old culms. The clumps are all about 1.5 years since planted and all starting to upsize this year. Last years culms are thin, tall and lean at awkward angles with the weight of the leaves taking up all my side yard space. So, I’m thinking the older culms are still providing lots of energy through the leaves but are also a drain or water available to the new shoots. Also, when it’s windy, the old thin culms can whip around damaging the new shoots.

So should I trim the thin culms (as much as 50% of the leaf mass)

1. In early spring before the big shoots start
2. Later spring/ early summer when the big shoots are growing
3. Late summer / fall after this years shoots are up but before they leaf out or
4. Winter / early spring after the big new shoots have leafed out?

This question primarily applies to sunburst, emeiensis (both) and dendrocalamus minor but to a smaller extent to the Asian lemon, barbellata and gracillis as they shoot year round. The gigantochloa loses the top half of its culms every winter so it keeps everything green so it can keep upsizing.

Any suggestions would be great - Thanks!

[dependable]

If you are trying to grow the planting, don't trim them at al until they start to loose color or past prime.

If you are trying to maintain at around present size, I'd go for pruning later in summer, or perhaps fall or winter.

[needmore]

The general advice I was given is to keep all cums for 3 years, I break that rule all the time as I'm willing to live with the adverse impact it can have - I'm not convinced that it does. One option with leaners like that sometimes is to weave them back among the bigger guys but then they are in the center of the clump and might not be helpful there.

My subtropicals gain size so quickly that I have been lightly culling the much smaller stuff in year 2 and they seem to keep going, who can say what they would have done if I didn't, I'm pleased with what I have.

As far as timing I always pruned my running bamboo right before shooting season, with the tropicals I pay less attention as I do not know when shooting season is. I just heavily thinned a few clumps last weekend and I'm starting to see shoots on Oldhamii, Pervariabilis, the Chungii seem to always be shooting as do most of my forms of B textilis so I just cull when I feel like the culms I leave look robust and will have lots of leaf mass.

However I would not thin clumps when there are multiple shoots already a few feet tall, I would wait until those are developing their own branches before I'd cull anything.