I would wait until the branches you plan to cut are mature — a woody brownish green or dark green. Branches that are not woody (immature) tend to rot more easily. If you have non-woody branches that you really must cut now, I would root them in a sterile rooting medium that is barely damp. Stick the pot into a large baggie, seal and place it under grow lights or in strong but indirect lighting. Don't open the bag until you see good strong growth or you can see that the growing medium is dry and need to moisten it again. If you have rooting hormone, use it on immature cuttings. It's not needed on mature cuttings, but it does seem to help protect immature ones from rot and helps rooting go faster.
Another way to root cuttings would be to air layer them. Air layering is usually done on woody plants, but can be done on non-woody ones as well. Just be careful that direct sunlight doesn't hit the pot or the heat will kill that part of the branch buried in the potting mix. Use a light colored pot if you have one or you can use aluminum foil instead of a pot. Anything to help insulate the potting mix from the heat.
http://aggie-horticulture.tamu...
http://www.youtube.com/watch?v...
