I am interested in the same question. I have had good success starting elderberries in nursery beds as dormant cuttings and growing for a season before transplanting. The only problem I’ve had is dealing with massive root systems that are difficult to dig. So far, I’ve only been planting them as field edge species, but will be starting my first cultivated varieties this year. To piggyback on your question about using AEA products, my question is “What nutritional challenges/needs are common in elderberries? I have crazy variation in the elderberries (native species) I’ve planted. Some growing to a 10’X10′ bush in only 2-3 years and others only filling a 3’X3′ space.