If you live in USDA zones 6 and 7, early March is usually the proper time to re-awaken containers of tender tropicals stored in your garage or moved in to join your house plants last fall. Likely, they’ve already begun to sprout. Specifically, angel trumpets (Brugmansia spp.), elephant ears (Colocasia spp. and Alocasia spp.), cannas (Canna spp.), and non-hardy bananas (Musa ensete), revive the dormant plant now. Replant into new potting soil, prune off old or dead leaves, and begin a regular watering and feeding program.
Purchase a good porous potting soil (media) from a local garden center. Replace most of the growing media in the old pot or shift up into a larger container. Try not to break many roots if they’ve already sprouted. Tender water garden plants such a tropical water lilies (Nymphaea spp.) and tropical lotuses (Nelumbo spp.) are better planted into drain-free pots containing ordinary garden soil. Soil-less media tends to float out the top when the container is submerged into the water pond.
Feed pots with an 8-9 month rated slow release fertilizer. Rate and directions should be listed on the package. Cover the soil (media) surface with 2-3 inches of large pea gravel to prevent any soil leaving the container and contaminating the pond. When all danger of frost has passed, moved plants outdoors.
Angel trumpets and cannas generally do not flower in the winter months. Replant into fresh soil-less media before moving the container(s) outdoors, about the time you transplant tomatoes in the garden.