Containers aren’t just for annuals.  I plant lots of perennials in containers and find that hostas perform especially well.  Experiment with different plant textures and colors.  Terracotta pots are great and I especially love the aged ones with a bit of moss growing on the sides.   Stone troughs, wooden barrels, old copper kettles, even tree trunks - all make interesting containers.  Stay away from plastic - it doesn’t allow the plants to breathe.  Lighten up on the soil mixture.  Soil from your garden is generally too heavy and you’ll need more air circulation in the container.  I mix up garden soil, a good potting soil and a bit of compost.  Just make sure that you have excellent drainage and pay special attention to watering and feeding.  Some containers can overwinter outside while others may need to come in the garage or potting shed.  Your only limitation is your creativity!