When you prune small limbs from a juniper that you feel has good bonsai potential, use the prunings to make cuttings. A trick that I learned at Auburn increases your chances of rooting tip cuttings. Junipers root readily if the cutting is made at the portion of the stem between wood that is one year old (or current seasons growth) and wood that is two years old. In the spring there is a distinctive color change that can be seen in the bark. The two year old wood will have a grey to brown color, while the one year old wood retains a greenish tint in the bark.
Being the naturally lazy person that I am, I stick cuttings into the soil of a potted plant that I know I will water (in this case Prunus angustifolium) and leave them alone for a while. My J. procumbens cuttings are well callused. Next spring I will move them to separate pots to start growing them out.
Beth
pruning tip for junipers
You don't make the cut 'between' the new and old wood - you include a couple of inches of old wood on the cuttings and stick the cuttings so a small portion of old wood shows above the soil.
Al
Thanks, Al. I did not include enough info, obviously. I have had good luck with cuttings that did not include as much of the older wood as you recommend, but perhaps I was lucky.
Beth