What is Lithodora? This ground cover, botanically known as Lithodora diffusa, produces large quantities of star-shaped, tiny flowers intensely blue from late spring through most of the summer.
Lithodora grown in gardens can reach heights of 6-10 inches (15-25 cm). A single plant can grow to 24 to 36 inches (61-91 cm). Lithodora can be grown in USDA zones 6-10.
The thick, dense, dark-green foliage of the southern ranges is green all year. Rock gardens will love the Lithodora groundcover.
It can also be used in containers and window boxes. It is easy to find it in garden centers.
Plant Lithodora seeds in your garden or indoors several weeks before planting. In mid-to-late spring, you can also propagate cuttings of established plants.
Growing Lithodora Groundcover
For Lithodora gardens, acidic and well-drained soils are best. Although sandy soil is acceptable, the plant will not tolerate clay soil.
Even though it thrives under full sun, it can tolerate partial shade. In hot climates, afternoon shade is the best.
Lithodora Care Requirements
Water it regularly and make sure the soil does not get dry. Avoid overwatering. If you live in a cooler area, mulch should be applied in autumn.
If the plant’s leaves look sloppy or damaged from the winter cold, prune them lightly. Lithodora does not require fertilizer unless the leaves turn pale yellow-green.
If this happens, provide fertilizer for rhododendron, azalea, or other acid-loving plants in late winter or very early spring.
You can treat aphids by spraying insecticide soap on the plant. Pests are rarely a problem.
Lithodora Diffusa Interesting Details
Lithodora diffusa (until recently Lithospermum diffusa) is poised to be a popular new spring perennial.
A compact groundcover, it has dramatic star-like blue and white flowers. Palle Olsen, managing director of Newplants New Zealand, agents for Lithodora Star, says it is the first time two contrasting colors appear on the same petals in this species.
Highlights of the new plant include an unusually long flowering period, from spring through to mid-summer, its compact nature, easy growth, and maintenance.
Lithodora Star is now grown commercially in six countries around the world, including New Zealand.
It enjoys free-draining soil, preferably humus and lime-free, and full sun. It is ideal as a groundcover, on a bank, over a wall, or in a patio pot.
It needs very little pruning and will last for about five years.