Agree that it's very important to have a stable base for the wreath. You might be able to wrap ribbon tightly around it as additional decoration and also to help stabilize the circle. Otherwise you could try unobtrusive loops of wire or something like that--anything to keep the base from falling apart.
My mom and I have adapted a couple of old wreaths that were made from natural materials, but had seen better days. We added fresh ribbon, and then took some of those cute tree ornaments which have broken over the years so you can't put them on the tree, and we glued those onto the wreath. We do use a hot glue gun. It's a little scary but not as big a deal as it seems. I don't know about glues but the hot glue gun just seems to work better when you have mixed materials and uneven surfaces. Just glue the heck out of it--that pretty much defines our craft projects!
My mom and I have also been working on another type of wreath. You get this wire frame from the craft store--like there are four rings connected like a bull's-eye. Then you get some fabric--remnants or fat quarters or something. Cut the fabric into strips--I try to go for 1 inch wide, and about 8 inches long. Then, tie the fabric strips around the metal frame--like a double knot, with the ends dangling out. After a long time, you get a fluffy fabric wreath which looks very festive, which you could then glue stuff onto if you want. It takes way more fabric than you imagine it will, and quite some time to tie it all on, but it's something you can do while watching TV or whatever. We have made two or three already, and we have also tied the fabric strips around strings of lights that will go on the Christmas tree. That makes a nice, rustic/country sort of look.