Rieger Begonias are one of my favorite indoor flowering plants. Their many-petaled blossoms come in colors that remind me of delicious candies; clear pinks and salmons, bright yellows and oranges and deep, velvety reds. The large blooms are contrasted nicely against lush, deep green leaves. But best of all, they can easily bloom for 6 months indoors with proper care.
I care for Riegers almost the same way as I care for African Violets. I provide them with bright, indirect light. (I find placing them just off of an east facing window works great. ) I water them when the soil feels dry to touch, giving them enough water to moisten the soil, but being careful not to leave the plant in standing water. (They really hate wet feed). For feeding I like using a liquid African Violet fertilizer every other week at half strength. Plants enjoy our indoor temperatures as long as they are kept away from indoor heating. They also prefer a bit of extra humidity so placing them on a tray filled with gravel and water increases the humidity around them. I don’t like to mist them as I find they are a bit prone to powdery mildew.
Occasionally the blooming stems can get heavy as they grow and bloom, so staking might be necessary. I also keep a watchful eye for aphids and whitefly and treat with an insecticidal soap at the very first sign of them. I continue to pinch spent blooms until they are done blooming. At that time I pinch back all the bloom stems to where the majority of the leaf growth begins, the plant will take a rest for about a month and then I’ll get another bloom out of it. Not quite as spectacular as the first, but still lovely.
After the second bloom, you can cut back and wait for your begonia to bloom again, or you can take leaf cuttings. Leaf cuttings are a fun way to make more plants and not at all difficult to to do. (Jon Van Zile does a good job explaining how to do that here.) But I’ll be honest, I have limited space and finding a spot where the begonia can regrow after being cut back or cuttings can root is difficult. Plus, I miss my showy bouquets of flowers. So after the second bloom, I compost the parent and pick up another one. When you consider the cost of one begonia and its length of bloom against what you would pay for cut flowers during that time, it’s still a pretty good deal. Also, it means I can get a different color. And just look at all the colors out there.