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.
Caring For and Planting Rhododendrons. In order to understand the culture of rhododendrons it is helpful to visit mountainous areas where they flourish. If you take a fistful of soil at their roots you will find that it is not dirt, but dead and dying plant debris. The fallen leaves, twigs and flower parts decay into what is called humus.