Hi petmar, For Erica's You can either take heeled cuttings (pull a sprig away from the main branch) 2.5-5cm (1-2in) early to mid summer.
Or you could try mound layering in early spring - Make a mound of ericacious compost over an established plant and allow it to root into the new compost and check on them after 4-6 weeks to see if they are rooting.
For Calluna's Take the cuttings the same but in late summer and put the cutting in a proragator with bottom heat or green house. In each case use a rooting hormone powder or gel Good luck Tbird+
Hi again petmar, If you decide to go down the 'mound layering' route, which is good if your plants are old with died -out middles, a piece of chicken wire pegged down over the mound should stop birds poking around with their beaks. Good Luck Tbird+