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.
Rhododendrons and Azaleas can be planted at any time of the year, even when they are in bloom, but it is best to plant them in the early fall so they have a chance to adjust to their new home before winter comes. They must be grown in an acid soil, with a pH of 5.0 to 6.5. Rhododendron and Azalea plants will not tolerate lime.