Hi Michael,
I have some experience propagating from cuttings, and recently did some research in anticipation for a large cultivation project for a 10 acre swale/hedgerow pasture system. I am propagting cold hardy evergreen bamboo hardy to below zone6 to be used as cut winter forage.
anyways, I need a lot of it and will be going forward with way seems to work well. These are two techniques I learn from someone who worked in a nursery for most of her life, and propated bamboo a lot.
first method, to be done in the mid-late winter when the plant is least active and has the most of it's energy dedicated toward the roots.
Select a rod from an existing clump, at least 1 year old. Older ones are better, hardy, and have more energy in the plant body, and are less engaged in active shoot growth.
make sure the rod looks good. it should be healthy looking and not succumbing to fungal infection or rot.
cut the rod at the first node after the rod start branching. the lower nodes will be far less likely to survive. Not even worth it. perhaps you can make a flute from those.
now cut the inter-nodes, leaving about 1-2 inches of inter-node material on either side of. Make sure your cut is nice and clean/smooth and not all jagged.
You should now have a node with one or more leaf-shoots sticking out, and 1-2 inches of internode on either side.
Select the best leaf shoot and cut off all the other ones.
Take some organic raw honey and coat the two cut ends. The honey is naturally anti-fungal, and provides sugar that the injured plan cells can directly metabolize and use to begin repairing themselves.
if you have some rooting hormone, apply it to the node.
put the cutting leaf side up in a potting mixture, about 1 inch deep. place it in a potting soil mix. (a good mix is 1 part rich
compost or worm casing, 1 part sand, 1 part broken up moss).
mulch it a few inches, and keep is moist through the rest of he winter. It should quietly root itself and begin leafing out in the spring. give it a few months of growth in the pot, and plant it out. or, wait until next winter and plant when it is dormant.
success rate, depending on the rooting temperatures (warmer is a bit better if you live in a cold area) is 60-80 percent on a commercial scale. always add in a margin for error when you are learning though!
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The second method is similar to the first, except you cut the bamboo into 12-18 pieces, instead of at each node. leaving a single leaf-shoot on each node and 1-2 inches of internode on both ends.
You can then plant the whole large cutting in the ground.
The benefits of either technique depends on how much bamboo you have to work with, how many plants you want to propagate, how hardy you need each individual start to be, how many pots you have, etc. I plan on doing some of both. But a heck of a lot more small ones.
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as far as clumpers vs. runners...I am a big proponent of the clumpers in most every case. particularly if you are in an urban/suburban setting where neighbours are concerned. Unless you set up some kind of root-zone or otherwise biological control (like a grazing paddock to continuously eat down new growth) the bamboo will probably dominate everything else.
cheers,
Andrew