Tree of the Week: Pink ball tree
Pink Ball Tree, Tropical Hydrangea -- Dombeya x cayeuxii
During late winter, the strikingly beautiful flower heads of the pink ball tree hang like upside down hydrangea flower clusters from the tree. So uncommon here that the Sunset Western Garden Book does not list it, this tree is often improperly identified. It is confused with the very similar original pink ball tree, Dombeya wallichii, from East Africa and Madagascar, but it has three-lobed (instead of five) leaves, is more floriferous and has somewhat larger flower structures. In 1895, Henri Cayeux, director of the Lisbon Botanic Garden in Portugal, created the tree by crossing D. burgessiae with D. wallichii; the result was named after him, with the x indicating its hybrid status.
A medium-fast grower, the plant has a tendency to be dense and shrubby. It will reach 15 to 20 feet tall and a little wider. Pruning it to a single trunk and strong branch framework will counteract weak wood and branch attachment. Large, hand-sized, heart-shaped, three-lobed velvety leaves are covered with soft fuzz atop and underneath. The leaves may turn a deeper color in cold weather, but the tree is evergreen where the temperature is above freezing. Dense, long lasting, 5- to 6-inch big balls or clusters (technically "umbels") of fragrant little pink flowers cover the tree in late winter. They turn brown after blooming; at that point the tree looks neater without them. Inconspicuous fruit capsules split into five parts at maturity. Without flowers, the tree is not particularly interesting. The pink ball tree will take full or part sun and a variety of soils. It is moderately drought resistant once established, but looks best with some water. Several varieties are available.
This frost-tender tree does well in USDA hardiness Zones 10 and 11; mainly the Southern California and South Florida coastal influence areas.
-- Pieter Severynen
Photo: Pieter Severynen