The epidermis of petals also form a variation of trichomes called conical cells. These cells all develop from the pavement cells, which make up the majority of the plants surface cells. In short, cellular differentiation of the epidermal cells is controlled by two major factors: genetics and environmental conditions.
Azaleas and rhododendrons thrive in acidic soil. Azaleas and rhododendrons thrive in the acidic soil that is common under pine trees. Both plants are classified under the genus Rhododendron; the main difference is the smaller, funnel-shaped flowers on the azalea.ake soil samples from the area under the trees where you want to plant the azaleas or rhododendrons. Mix the samples in a bucket and test with a soil pH test kit.
The usual time to prune a rhododendron shrub is after the flowers fade. This timing preserves the buds that already formed for next year's flowers. Because severe pruning prevents flowering the following year, you don't have to worry about preserving the flower buds, and it's best to prune as early as possible. rhododendron's natural shape fits well in informal gardens. Rhododendrons (Rhododendron spp.) have an attractive, natural shape that may lead you to believe they don't need regular pruning. They generally grow in U.S. Department of Agriculture plant hardiness zones 5 through 9.