How to Maintain Rieger Begonia Flowers

Plant the Rieger begonia where it will be in filtered sunlight or partial shade. Avoid full shade, as lack of sunlight results in tall, leggy, unattractive plants.

Water the Reiger begonia lightly when the top of the soil feels slightly dry. Although Rieger begonias tolerate dry soil, the plants won't survive in soggy soil. If your begonia is planted in a container, check the potting soil daily during the summer, as soil dries quickly in a container. Use only a container with a drainage hole. Avoid wetting the foliage to decrease the risk of powdery mildew.

Feed the Reiger begonia monthly, using a water-soluble fertilizer with a ratio of 15-30-15. Mix the fertilizer according to the proportions recommended on the package.

Pinch off, or deadhead, wilted blooms to keep the plant tidy and to promote more blooms. If the plant looks overgrown and untidy in midsummer, trim with garden shears as needed to reduce legginess and maintain a bushy, compact plant.

Bring the Rieger begonia indoors before the first frost in autumn, as the plant is tender and won't tolerate frost. When the begonia begins to look faded and wilted, withhold water for two weeks. Thereafter, cut the begonia back to three to five leaf nodes, which are the protrusions where leaves grow from the stems. Resume watering after you have pruned the plant.