If you are in search of a prolific blooming, colorful flower for shaded areas in your landscape, look no further than the tuberous begonia. Begonias can be grown directly in the garden bed or in containers on patios and decks. They bloom from early summer until the first fall frost, adding season-long color to the garden. They aren't frost hardy, but the tuberous roots of the plants can be dug up each fall and stored over winter. Root the tuberous begonias in spring after all danger of frost has passed.
Prepare a well-draining garden bed in a full to partially shaded area. Lay a 2 to 3 inch layer of compost over the bed and till it in to an 8 to 10 inch depth to add organic matter and aid water drainage from the site.
Dig a shallow hole and sit the tuberous root inside so that the indented side of the tuber faces up. Cover with ½ inch of soil then water thoroughly so the bed is evenly wet. Space plants 18 inches apart in the bed.
Fertilize at planting with a half-strength general soluble fertilizer, following label instructions. Repeat fertilization every two weeks throughout the growing season.
Water begonias one a week, providing approximately 1 inch of water per plant. Water only when the soil in the bed is beginning to dry, otherwise the ground may become too moist and cause the begonias to rot.
Pull weeds from between the plants or cultivate the top 1-inch of soil to prevent weed seed germination until the plants root and sprout, approximately one to three weeks after planting. Once begonias begin growing they will quickly shade out any remaining weeds.