Lithodora planted in gardens reaches heights of only 6 to 10 inches (15-25 cm.), but a single plant can eventually spread 24 to 36 inches (61-91 cm.). Lithodora is relatively easy to find in garden centers. Otherwise, plant Lithodora seeds directly in the garden, or start them indoors a few weeks ahead of time. You can also propagate cuttings from established plants in mid- to late summer.