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.
The best planting depth for bulbs is generally three times the size of the bulb. For oriental lilies, 6-inches is a good depth. Asiatics can be planted 4 to 5 inches deep. Adding some bulb food or bone meal gives them some phosphorus to start. Interplant the ferns and lilies by planting them in an alternating pattern 10 inches apart.