You could almost turn them into a hedge.
The cuttings would grow better in the warmer, wet months I think.
I've been thinking about doing a Mexican Sunflower hedge along the fence line. It also grows very prolific and has big yellow flowers in summer.
I did quite a few cuttings after the last rain in autumn but most didn't make it through winter.
The Mexican Sunflower is seen as a weed here because the cuttings root so easily. You need to regularly prune it to stop it falling over & rooting.
The elderberry doesn't have the same stigma as Mexican Sunflower.
