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.
Planting. 1  In mild climates rhododendrons and azaleas can be planted almost any time of the year with reasonable success. In colder areas, early spring planting is recommended, with early fall planting being a second choice. 2  Rhododendrons and azaleas do well with direct light for at least part of the day. Excessive shade normally results in very limited flowering. In hot areas, northern exposures are preferable to southern exposures. Exposure to constant wind is not desirable, especially the salty winds of marine environs.