The germination of ericaceous plant species is often variable and not well-defined. We have had some difficulty in obtaining good germination and significant establishment and growth after transplanting. Four different moisture regimes and two different media were used for the germination of Kalmia latifolia, Oxydendrum arboreum, Rhododendron maximum, and Vaccinium corymbosum seeds. Seeds were surface-sown on peat or peat + bark (1:4) media. Pots were then placed under either one of two different misting regimes, set in a tray of water, or set in a tray of water under a humidity tent. Germination was higher and more consistent for all species sown on peat and occurred sooner for seeds under the humidity tent. Rhododendron and Kalmia under the humidity tent grew more rapid than with other treatments. Increases in germination under the humidity tent were due more in part to higher temperatures than to the minimal increase of humidity inside the tent. Germination was poor for seeds under the high-mist treatment, presumably because there was too much moisture. Germination of Vaccinium and Oxydendrum was low for all treatments.
Phytophthora stricta Isolated from Rhododendron maximum in Pennsylvania
