THE TRIFLORUM SERIES
The Triflorum series, as given in the latest R. H. S. Handbook, includes thirty-one species. This represents some decrease in numbers as several species have been merged. For instance, R. oreotrephes now is considered to include R. artosquameum, R. exquisitum, and R. timeteum.
The flowers of most species in this series are rather small, the leaves are relatively small, some foliage not especially decorative, and the growth may be rather willowy and open. Certainly they are not rhododendrons to be grown as specimen plants for extraordinary size and color of flower. Their value, however, lies in their suitability for landscape use as flowering shrubs, preferably to be viewed at some little distance, and if possible in front of evergreens or other dark background. Some of the best of these plants will be completely covered with medium to small, light, airy flowers, most beautiful if seen from a little distance. Some are semi-deciduous, others have beautiful foliage sometimes suffused with a rosy hue encompassing both leaf and twig. Colors range from white through pink to lavender with some blues in R. augustinii which are probably the best blues in the genus. A word of warning should be included, of course, that many seedlings of R. augustinii are inclined to be a dirty mauve, and that only the best selected forms have really good blue color.
The casual garden shopper usually has in mind a large flowered rhododendron with a strong pink or red, or possibly white color. The Triflorum types have not yet caught on as they should. As time goes on, and they are used more in the landscape, and properly used, they will eventually be considered as some of the finest flowering shrubs available.
We do not find extreme hardiness in this group but a number are in the H-3 listing and of course where this happens there is always the possibility that a hardier than usual seedling may show up somewhere to increase the range over which the species may be successfully grown. In the Northwest there are many places where a number of the Triflorums can be used in the landscape with safety. These species are worthy of much wider use. It would be nice to have in the Bulletin a really thorough article describing the different species of this series now available with their faults and advantages.