you could do it either way. You could also make a block quilt then applique the flower garden in one corner instead waiting to do an entire flower garden, etc. Do what is at your comfort level if you want to use them right away. If you don't like the fabrics, cut them up into squares to use in a scrap quilt where they'll be lost in fabrics you do like. You can always make small wall hangings - depending on the size or number of blocks you have. If the flower garden blocks are cut but not sewn, stitch them onto a solid background with some space between them as sort of a stained glass quilt...the ideas are endless.
Would you rather have parts of GGMs quilt where you can see it to remember her or have it stored away again for how many years????