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.
Plant spacing. Plant 3 feet apart. It's important to give the plumbago plant plenty of space...the rambling growth can overtake its neighbors unless the shrub is spaced properly to begin with. Plumbago looks fantastic cascading over the sides of a planter or container.