Harriet, that is such a clever idea for wall decor that can easily be changed for each season & holiday without making whole new wall hangings.
That goes along with an idea I saw at my sewing group a few months ago for using a neutral pillow with different bands which can be as simple or elaborate as you want. I googled "pillow band" and the first link that came up was from Martha Stewart:https://www.marthastewart.com/266612/pillow-bands
Martha's version has a pretty front side and then it wraps around the pillow and is fastened with a velcro strip in the back.
My friend's version had the band as a tube that slipped over the pillow, and she decorated both sides of the band so all she had to do was turn it over for a new look. She put Halloween on one side and Thanksgiving on the other. She also showed a red band that had Christmas on one side and Valentine's Day on the other. Hers were printed fabric so they stored flat.
I was thinking that with so many gorgeous specialty yarns in the shops these days, it would be easy to knit or crochet pillow bands in any color combination for inexpensive home dec.