I know everyone in St. Louis is worrying about the affects of this harsh winter on our beloved bamboo groves....well at least some of us are!
Our local bamboo expert, Alan Lorence, provided me with this information. Check out Alan's blog HERE
Rough winter for bamboo for sure. In general, there are a few levels of damage that occur to the arboreal (tree-like) bamboos:
1) Leaf burn. This is when parts of leaves get that dried, light green/gray look, or possibly brown, but parts of the leaf stay green and healthy.
2) Leaf kill. Entire leaves get dried, crispy, curly. Interior parts of larger bamboo plantings may still have leaves that are undamaged or only slightly burned. All of my bamboos show this kind of damage this year (Yellow Groove is in this category)
3) Culm kill. Not only do all of the leaves on a culm die, but the dormant leaf buds are killed too. I suspect that all of my plantings have some culms that have been killed and will need to be removed after it warms up. (Yellow Groove is probably in this category too.) Note that some bamboo growers have observed that dead culms take on a darker color, and will start to smell like alcohol once it warms up a little -- the sugars in the dead culm have started to ferment.
4) "Top kill". Everything above ground has died, no culms survived. The rhizomes will still produce new shoots, but they probably will be smaller than the previous years'. I suspect that I have a few species that are in this category. The black bamboo is a good example of this. This could happen to a small or young planting of Yellow Groove, if it's not dense enough to self-shelter some of the innermost culms.
5) Rhizome death. If it get brutally cold and there is no snow cover, all of the rhizome buds can be killed too. This results in a dead plant that won't come back. This will never happen in St. Louis, or if it does, we have more things to worry about than how our bamboo is doing.
For the shrubby bamboos (like the big-leaved varieties you got from me last year) you've definitely got leaf kill, but will have to wait until spring to see if they'll leaf back out. I'll probably shear all of the leaves off but leave the culms standing. If they don't start releafing I'll cut them down to the ground before they start shooting.
For groundcover species (which typically topkill every year anyway) I just mow them to the ground before they start shooting.
Hope this helps!