Before covering your last plants with potting soil, put in your top plant and then add extra soil. Some of my favorite plants to use in strawberry jars in the bottom holes are Mexican heather and Dreamland zinnias. I like compact plants at the bottom. For the second level of holes, I like plants like asparagus fern, periwinkles, begonias, ageratums and marigolds. For the upper layer of holes I like the cascading plants like New Wonder scaevola, Tapien verbena, purple wave petunia or Surfinias and New Gold lantana.
All lantanas are well suited to put some place in a strawberry jar because of their heat tolerance.
A strawberry jar is an excellent choice for creating a small herb garden. Fill the holes with oregano, lemon thyme, parsley, cilantro, chives, mints, and an erect rosemary on top. These are just a few of the choices. Your garden center is loaded with herbs right now. And lastly, you can plant strawberries and have a bountiful harvest of cascading red fruit.