We live on Cape Cod and our bamboo is doing pretty well, but every spring about 50% of the shoots that come up, die back while they turn yellowish and get weak.
A neighbour called it 'damping off', but Ive not been able to find out what to do to prevent this.
The first shoots that come up are robust and grow like crazy, the last ones come up, stop growing, turn yellow, start to tip over and weaken, then stop growing. If I even bump them, they just keel over and break off.
I hope somebody can help us to determine what is doing this.
I think my pictures will do better than my words, so I quickly put a quick page up to show what the problem is,
(Sorry about the wild colors on the backgrounds of my page, Im taking a CSS class.)
http://www.jcarter.net/bamboo/bamboo.html
And advice sure will be welcome,
Thank you,
Jane

Jane, welcome to the forum, although 50% seems too high of a ratio bamboo nearly always produces more shoots than it can sustain. These start out looking like normal shoots but often their growth stops and they are 'held in reserve' should something happen to enough of the growing shoots then these may wake up and start growing again. Think of them as backups that are hopefully not needed. Generally they will abort as you describe, sometimes at the few inches height while other times a bit taller before they collapse. Totally normal behavior.

Since the plant perhaps is aborting more than may be typical, you may wish to focus on feeding practices during the summer to build up good energy for the next round of shoots spring 2012.

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Brad Salmon, zone 5b/6 Southern Indiana
Winters -20 to -25C. Summers 30 to 35C , humid. 115 cm annual precipitation, frost free from May through early October. 259.3 meters elevation. Growing 150+ species. http://www.needmorebamboo.com/

Jane - believe it or not, that's probably normal. A grove will send up many more shoots than it "needs", and the later ones will "abort" like that. They start fine, reach a few feet or so (if that) and then stop, get soft, and shrivel up.

If it were *every* shoot doing that I'd be concerned, but what you described sounds normal to me. I think others will agree with me.

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Alan.
My blog: It's not work, it's gardening!

Thank you for the explanation!
I guess its really more like between 30 and 40%, but really had us worried.

Ive not seen this in the tropics, just here in the north, so I think thats what the worry was. I was thinking that some fungus or something bad was gaining on us.
In previous years it didnt seem to take quite the toll as this year.

I sure feel better about this now, and wont be so upset.
Jane

I've seen the same exact thing from the grove where I got my yellow groove division. In 2009 it made a huge number of upsized shoots, some getting up to 1.25 inches in diameter, and breaking 20ft, but in 2010 when I looked at it again, it made an unusually small number of shoots, a bit downsized, and nearly half of those aborted.

My YG grove exploded with 34 shoots last year, but this year it seems to have the same pattern where it only successfully put up 11 which are slightly smaller than that of last year's. I've read up about them having on and off years, but I really don't know why it does that.

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http://www.flickr.com/photos/31489820@N02/

http://stevespeonygarden.blogspot.com/

Thank you everybody, I now understand that our Yellow Groove bamboo is behaving properly and nothing is wrong.
Jane

Very probably, its exactly what everyone is saying- normal. But to me, your grove looks kind of mature size to be doing so much of it. This year, I lost extremely high numbers in a maturing grove, and discovered it was earwigs doing the damage.

When a culm aborts, it looks different than what's happening in my groves this year. Here's what I'm seeing from earwigs: A shoot looks great, but at a particular node, it dies from that node, and all the shoot above it will snap clean off if you barely bump it, and the portion that came off will be thin walled and weak for a portion just above the break, and the culm sheaths will be wet and spongy. But further up the shoot, its normal, solid feeling, dry sheaths... but maybe not as healthy as it was just a day before when I've gone out to watch it grow. Below the break, its already shed its sheaths and is very healthy. But sometimes, a node or two below where it snapped, I can find surface gouges in the culm that rise up from the node, and peter out before reaching too far up the internode. If the culm hasn't hardened off, the gouge will be weepy. If I look around, I see other patches like that on mature, hardened off culms. Its a very different scar than when rubbing wears a patch onto the surface.

So I got to sleuthing around (aka crawling and contorting) in my grove, and found that earwigs are tucked in their thousands under dry sheaths, nibbling away. They move along when a node weeps a section into saturation. They're not tucked in for the day out of the sun under a cool sheath- they're dining. I observed them directly eating, not just observed that they were present.

They seem to have a preference for aureocaulis and spectabilis, and don't bother nigra at all. I've got a list of what they haven't bothered that's longer than what they have- basically, they've destroyed this year's spectabilis, ruined the aureocaulis mixed with it but not bothered the aureocaulis planted by itself elsewhere in my garden, and I suspect they're in the castillon, but it's only just started to pretend its going to shoot this year. The aphids love that one, which is why I suspect the earwigs will too.

It may have just produced more than it could handle so some shoots had to go which is very possible considering that your grove is pretty well shaded by surrounding trees.

I'm not sure if I'm getting the same thing, but some of my bamboos get sharp bends in their branches which seems to occur on warm sunny days. It wasn't windy either so could it just happen that bamboos over-produce and everything becomes a bit floppy?

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http://www.flickr.com/photos/31489820@N02/

http://stevespeonygarden.blogspot.com/