Comparison of the juvenile period of interspecific-cross seedlings in evergreen azaleas

We evaluated the time to the first flowering of the crossed seedlings of five species and one variety of evergreen azaleas (Rhododendron spp.) to obtain the basic understanding for controlling of the juvenility. It required three years after crossing for the first flowering in all crosses and over five years for obtaining of 70% flowering plants in most crosses. The length of the juvenile period of the seedlings was different by cross parent, whereas the difference by cross direction was not affected. The juvenile period was the longest in the crossed seedlings with R. simsii, and less than 35% seedlings flowered five years after crossing in some crosses.