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.
It has large green leaves and grows up to 10 feet tall. Rhododendron rubiginosum is hardy in USDA plant hardiness zones 7 to 9 and has pink or purple flowers. It can grow up to 20 feet tall and often has a rounded shape.hey stay between 6 inches and 3 feet tall and have purple blooms. Cloudland rhododendrons are hardy in USDA plant hardiness zones 4 to 7. Another type of rhododendron that grows well indoors is Rhododendron (subgenus Azalea) 'Brazil.' It is an azalea with orange flowers, hardy in USDA zones 5 to 8.