There are several small, blue-flowered Griffinias and even Griffiniopsis blumenavia (Hippeatrum/Amaryllis blumenavium). Both these are tender and need at least 75% shade. Also, I have Cyrtanthus hybrids (ex Greg Petit) that flower all winter long and is under 12 inches tall which would do well in a trough. Kevin Preuss http://www.amaryllis-plus.com/