WOW... that is a lot of questions. I will try to help answer as many as I can. I do not get here often but when I do I try to go to the questions that have not been addressed at all.
1. Should they come from any particular part of the bush? NOT REALLY. YOU DO WANT TO TAKE SOME OF THE OLDER CUTTINGS THAT ARE NOT TOTALLY GREEN. THEY ARE EASIER TO MAKE ROOT.
2. Should the ends be sealed? With what? I HAVE NEVER SEALED MY BRUGS BUT I LIVE IN ZONE 10B. WHEN YOU TAKE THE CUTTING START THEM OFF IN A GLASS OF WATER AND PUT THEM IN A SUNNY WINDOW OR IN FOUNT OF A GROW LIGHT. THEY WILL NEED THE SUN TO MAKE ROOTS. CHANGE THE WATER TWICE A DAY.
3. Should they be refrigerated? I DON'T THINK THE FRIG IS A GOOD IDEA FOR A TROPICAL PLANT. BEST LEAVE IT AT ROOM TEMP.
4. Should they be kept in sealed moist bags? CLOSED BAGS USUALLY CREAT MOLD FROM LACK OF CIRCULATION.
5. What other factors are important? THE ROOM TEMP SHOULD REMAIN AROUND 70 DEGREES TO 85 DEGREES. TAKE AND KEEP AT LEST 8 CUTTINGS SO IT YOU KILL ONE YOU HAVE 7 MORE TO GO! SHARE A FEW CUTTINGS WITH A FEW BRUGMANSIA LOVING FRIENDS SO YOU HAVE A BACKUP PLAIN IF IT NEEDS TO BE REPLACED. NO FERTILIZER UNTIL IT IS TIME FOR THE PLANT TO GO BACK OUTSIDE.
Can I take cuttings from this growing season and root and plant them to grow this season? YES. AS I SAID EARLIER, TAKING A FEW CUTTINGS WILL BE YOUR SAVING GRACE. IF YOU HAVE MANAGED TO KEEP ALL OF THE CUTTINGS ALIVE AND HAVE TRANSPOSED THEM INTO PLANTS, YOU CAN TRADE THEM NEXT YEAR FOR VIRATIES YOU DO NOT HAVE.
Begin pruning the plant when the main trunk forms its first "Y" and then prune back any older branches to encourage additional branching. Cut back as much as one-third of the plant. For larger plants, this could be as much as 1 to 2 feet
I HOPE THAT HELPED
