In the Northwest, over the last two decades, rhododendrons have become “everyman’s” shrubs. Gardeners in the Southwest are deprived of their beautiful flowers and the textural interest they create in the garden because they are not culturally suited to the area.
The rhododendron family includes the azaleas (not treated here), and the species and named hybrids are so numerous that there arc nursery workers in the Northwest who grow them exclusively.
Most rhododendrons are evergreen, and by careful selection, you can have them in bloom from December into August. Some form mat-like growth, others are true shrubs, and some are tree-like.
They all make ideal woodland companions for oaks and dogwoods and may be combined with many heath family members. Some are suitable for pot culture. Redwood tubs can be used.
Rhododendrons Needs Protection
Rhododendrons generally require acid, organic soils, protection from wind and light, and high shade. The larger the leaves of a plant, the more shade you must be prepared to give it.
As their roots grow near the soil’s surface, they should be kept cool and moist with a mulch or some unexacting ground cover such as mock-strawberry and Duchesnea indica.
Though most rhododendrons will accept temperature extremes, they will not tolerate drought. The moisture of the coastal regions suits them so perfectly that they thrive even in full sun.
Although there is an uproar of introductions, MRS, G. W. LEAK, and LODERI VENUS are still good pinks; UNKNOWN WARRIOR and DAVID are among the best reds LODER’S WHITE still holds a top place.
Propagating Rhododendrons
Propagation is by seed, cuttings, layering, or, more frequently, by grafting, which is a slow process. Seeds are sown on the surface of sphagnum moss and kept moist with bottom watering as they damp off easily—transplant when seedlings develop three leaves.
Cuttings of large-leaved rhododendrons do not root easily. In California, take half-ripened wood in June and July, and elsewhere in the Northwest in July or August. Insert the cuttings in peat and decayed pine needles and keep them moist until rooting occurs in about two months.
If you are interested in grafting, remember that scions from the current season’s growth are taken in California in December and January.
44659 by Lester Rowntree