Bedding flowers for under established trees
I have two trees out front along the side walk, an apple and a plum. Both are established trees (planted six years ago, one potted one bare root). Apple is on dwarf rootstock. I put in daffodils when planting the trees.. and they all seem to get along together. This year I decided to put in some bedding plants in the mulch under the trees.. African daisies and some ever-flowering cousin of petunias. They have really failed to thrive.. and haven't grown much beyond the size they were planted. Slow release fertilizer upon planting.. plenty of water to establish (and the daffodils as they finished), etc, etc. It might be in part to light levels.. but they get full sun for part of the day and dappled shade the rest. This being Utah, that is usually plenty for full sun plants.
There are too many roots to sink in pots of nice soil.. and pots above ground dry in half a day unless they are very large.
What are some good bedding plants for full/part sun that do well in drought conditions for next year? (I'll water them, but they are competing with a tree). I'm not worried about fruit production.. wildlife, codling moths, and wasps are the main consumers. I even watched a vole the other day trying to roll off a dropped apple half his size back to his tunnel.