[Image description: eight raspberry cuttings showing the stages of root development at their growth tips, with the leftmost cutting showing almost no root and progressing to the rightmost which shows a cluster of roots and upward growing leaves]
I'm giving a talk next month about reproducing plants asexually and am working on images for the slide deck. Figured I may as well share some of the images here too as it might help some folks who are interested in doing this. Questions and feedback are encouraged and appreciated, they'll help to make the presentation even more informative.
I'm in the process of cutting my black raspberries now - they're the ones pictured. My preference is to "tip layer" them, essentially leaving long canes with the tips pinned to the ground in early spring for cutting free around now. I leave other canes for fruit with a "heading cut" to force the side branches where the fruit forms.
I like fall planting better, but I'll qualify that with "for temperate climate areas". For New England in particular autumn is when insect pressure decreases, precipitation is a bit more regular, and temperatures are kinder to plants. Plus there's additional time in the ground for the plant to establish, and it's my belief that the warmer soil temperatures relative to air temperatures helps to drive root growth even while the aboveground sections are dormant.