Sign up for our newsletter
Gardening in the Rainy Zone.
Rhododendron 'Fastuosum Flore Pleno'
syn. 'Fastuosum Plenum'
Sunset zones: 4-6,15-17.
USDA zones: 5-8.
Heat zones: 8-5.
Height: 12 feet (4 m).
Width: 12 feet (4 m).
April to May.
Trusses filled with lavender-blue, wavy margined, double flowers with greenish blotch.
Medium-sized, evergreen leaves.
Full sun to part shade.
Humus rich, well-drained, acidic soil.
Lightly prune for symmetry after the shrub has finished flowering; rarely needs pruning.
Rainy Side Notes
When we moved into our home, I found a rhododendron languishing next to the foundation. The small shrub didn't appear as if it was healthy enough to live much longer, and I wanted to yank the thing out and pitch it onto the compost heap. Instead, I carefully dug it up and transplanted it to another location in a raised bed with deep humus rich soil. If it didn't thrive in its new environment, then it would become compost fodder. Seemingly, against all odds the sickly, small shrub began to grow and within months, adorned itself in new sets of leaves; it looked happy and healthy. When it flowered the following year, I was pleasantly surprised with its floriferous displays, starting out as purple buds and opening to reveal a double flower inside. Even with an unhealthy start, eleven years later it's a healthy six feet tall, continues to bloom contentedly, and will eventually reach 12 feet.
Every year a few notches from root weevils appear along the leaf margins; it's annoying, but the minimal damage to the foliage isn't enough to make me want to shovel prune it.
Bred in 1846 by Geber Francoisi in Holland, 'Fastuosum Flore Pleno' is a cross between R. catawbiense and R. ponticum. Cultivated for a long time, you don't see many double flowering rhodies. Unfortunately, this plant is as sterile as a mule, so its attributes can't be used to develop more double flowering, evergreen rhodies.
Photographed in author's garden.