When indoor-flowering tulips, narcissus, and muscari have faded, fill in the gaps with Sinningia speciosa, commonly called gloxinia. Capable of blooming anytime during the year, regal gloxinias produce rich, colored flowers. Exclusively cultivated for indoor gardening, gloxinia will not successfully transplant outdoors. But that's just as well, because you'll enjoy its tropical blooms better inside. Growing 8 to 12 inches tall, the soft, fragile-looking gloxinia blooms are surrounded by large, dramatic-looking leaves.