Sixteen Candles Summersweet. This is a seedling selection of Clethra 'Hummingbird' by Dr. Michael Dirr which is an improvement on its parent. It is more compact than its parent with dark green foliage and upright "candles" of white flowers on a plant that does not flop. This last attribute is its best claim to popularity. From a distance, it appears to be more uniform than 'Hummingbird' as well. Clethras like full sun to part shade for best performance, but will grow in diverse soil conditions. In its natural habitat it grows in wet soils, but will grow just as well on higher drier ground. In time, each plant will make a thicket.