My 4 rubros have been going nuts the last 2 or 3 weeks, putting up whipshoots like crazy. They are definitely not culms, as were seen in the spring, which were much bigger and sheated differently. Rubro is known as a very agressive plant. One of its characteristics is numerous "suit case handles", rhizomes that surface and then arc back down into the soil, leaving a visible "handle".

My other Ph., esp nigra, vivax, and henon, are also putting up whipshoots, indicating, imo, lots of Ph. rhizome growth here in the late summer, exploitng the energy taken into the rhizomes during the summer.

Containered Ph. of course has lots of perimeter whipshoots from rhizomes hitting the container and turning upward.

In general, I think whipshoots are smaller and have a longer tapering of the tip, while culms are more bluntly tapered.

In my mind there's not sure a clean delineation. Anything that's sort of slender, I call a whip shoot, but I think anything that actually grows up and has leaves is a culm.

whip shoots have branches and leaves, just like culms.

The whip shoots tend to be less straight than culms since they often come out of the ground way off vertical, and then bow up towards vertical.

My Rubo's (well all but one, that one seems to be needing remedial growth lessions - gotta put it on the short bus to photosynthisis school) have been putting up both clums and whipshoots all summer.

Nice to have them provide entertainment past the spring shooting season, between new clums and the "dolphining" (ya know when the rhizomes surface and dive down again) it's always fun to go see where the rubo is popping up.

Got some 6' to 8' clums from this mid summer shooting, first round this spring only went about 4' (from a 3 gal planted last spring (2004) that pretty much top killed this past winter), so the mid summer shooting has been pretty significant, bigger shoots and significant foliage added.

My other bamboo entertainment for the summer was watching a pumpkin patch expand into the red margin, kinda like a really, really slow wrestling match. Eventially I decided the pumpkin was actually winning (pinned the heck out of a few clums) and had to break it up.

I always thought a whip shoot was the end of a rhizome as opposed to a regular shoot coming out of the middle of one. This is why they are at odd angles and sometimes small. They are good for potting up because they are at the end.

"a whip shoot was the end of a rhizome as
opposed to a regular shoot coming out of the middle of one"

correct, afaik.

Bruce, because they are 'at the end of the rhizome' they do not always make good divisions. That part of the rhizome is the least likely to contain viable rhizome buds, so it is very helpful to include a couple of feet of rhizome that is still buried, when using whip shoots for new stock.

My Rubro is putting up some new shoots now too. It will be interesting to see if they make it into winter very far. I guess if they make it to January they can then be killed by subzero temps. Rhizomes, man, that's my only hope. Go rhizomes!

OK, I have a piggy back question: if you have a whip division w/o any viable buds, are you then out of luck no matter how long you wait? Can Phyllostachys eventually sprout a new bud? What if you take part of the culm and submerge it in soil, could this stimulate a new rhizome? Sort of like whipshoots turned culms in reverse.

Thuja, the rhizome can not form new buds, it must utilize the ones that it was 'born' with and in the whipshoots, they have nearly all been used for branches unless you include a good length of still buried rhizome. This is similar to an above ground culm not being able to produce new branch buds. Picture an above ground culm being buried so that the branches are now sticking out of the ground like little culms, once the buds have sprouted, there are no more new ones produced.

This topic has had me thinking and I need a consult with my bamboo 'expert' on something. He has taught me that the rhizome buds mature at different rates and that somewhat explains the sleep, leap, creep. I have posted this earlier and hopefully I'm remembering right, but assume that one has a 10 foot section of rhizome. In year 1, about 10% of the buds are mature enough to become new culms or rhizomes; an additional 20% in Y2; 30% Y3; 20% Y4 at which point around 80% of the buds have done something, and maybe 10% of the remaining ones in Y's 5 and beyond.

In the rhizome culm or above ground culm, it looks to me like all of the buds mature at once and these become the branches of the culm. My question for him is what causes the buds to all mature at once instead of the above 'schedule'? Is it merely exposure to sunlight? If so, then why don't the diving rhizomes shoot on the exposed parts?

"exposure to sunlight?"

That's my guess, plus maybe exposure to C02, for photosynthesis, in the air.

"why don't the diving rhizomes shoot"

I think there is quite a bit of communication within the plant, that somehow tells the exposed rhizome nodes not to bud as long as the meristematic tip of the rhizome is enterred.

Hoosier52: Yes, I do take some of the underground rhizome along with the whipshoot when I pot it up. It is fairly easy with a whipshoot since I can usually do it without disturbing much of the existing growth.

Hoosier, so your info: In year 1, about 10% of the buds are mature enough to become new culms or rhizomes; an additional 20% in Y2; 30% Y3; 20% Y4 at which point around 80% of the buds have done something, and maybe 10% of the remaining ones in Y's 5 and beyond leads me to conclude I shouldn't give up on my planted division for a number of years. I suppose I could dig it up and look for rhizome buds but that seems a bit extreme.