I usually wait until warmer weather (although it's been hot here lately in So Cal).

For me, I start rooting in April, about the same time as tomatoes get planted.

Can I keep the cuttings that long? I meant until April. Thanks!

I have for many years. I generally prune my plants around Super Bowl time. I keep them in the garage where it's not too hot until April when I do any rooting. I also take the remainder to a nursery and they root them with no problem.

I'm in Ventura which is also a cool climate. I've been rooting cuttings (30+) all winter on an outdoor heat mat (unprotected/out in the elements) and they are moving along nicely. The heat mat is the only way I root cuttings now....it just works so great and it increases the success rate and speed to get cuttings established. For single cuttings, i'll bag root them. For other cuttings that I got in bulk, I gang pot them in one pot and i'll separate them in early spring.

I cut over the next two weeks and then start planting in mid March. I am in Costa Mesa, Calif.