Basic structure of dicotyledonous stem-Sunflower stem. Inner structure of dicotyledonous stem reveals epidermis, cortex and stele. Epidermis. Epidermis is protective in function and creates the outermost layer of the stem. Epidermis is a single layer of parenchymatous rectangular cells.
Culture. Plumbago is propagated from cuttings in the summer, but you can also grow it from seed. Plant plumbago in light, sandy, well-drained soils, spacing each shrub 36 to 60 inches apart to allow room to grow. If spaced properly, blue plumbago will naturally cascade in a fountain shape.
Plumbago will grow in a cascade down retaining walls. Blue plumbago (Plumbago auriculata) is an evergreen shrub that is native to South Africa, but grows in U.S. Department of Agriculture plant hardiness zones 8 through 11. With long, thin stems and pale blue flowers, itâs prized as a shrub, climber, potted plant and groundcover.