I don't know your area at all, climate-wise (or anyway-wise) but perhaps I can be of help.

Regarding Viburnum, can you tell me what you are currently doing that leads to failure?

I worked in several plant nurseries for years. I never tried to root the plants you are asking about. Some plants only root under a mist system. I think viburnum would root easily. How long are your cuttings and are you using woody ones? What are you putting your cuttings in?

I just learned form my horticultural friend that viburnum cuttings need to be grown under mist if they are soft wood cuttings.