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.
Set tubers of tall types (more than 2-1/2 feet) 3 to 4 inches deep and 20 inches apart. Shorter varieties should be planted 2 to 3 inches deep and 10 inches apart. If you buy nursery-grown plants at local green houses, plant them at the level they grew in their pots.