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Gardening in the Rainy Zone.
Lithodora diffusa 'White Star'
syn. Lithospermum diffusum, L. prostratum
Pronounced: lith-oh-DOR-uh dy-FEW-sa
Sunset zones: 5-7, 14-17.
USDA zones: 6-8.
Heat zones: 8-6.
Height: 6-12 inches (15-30 cm). Width: 18 inches (45 cm).
Blue flowers with 5 petals arranged like a star; each petal has a white stripe down the center; the opposite of blue star—white flowers with a blue stripe down each petal.
Narrow, dark, hairy, evergreen leaves.
Partial shade to full sun.
Well-drained, neutral to acidic soil. Does not tolerate alkaline soils.
Prefers lean soils; fertilize sparingly.
Take semi-ripe cuttings in summer.
After the plant is finished flowering, dead head for appearance. If necessary, sheer old plants before wood has hardened off, preferably after flowers are done.
Pests and Diseases:
No serious problems in the Pacific Northwest.
Rainy Side Notes
Lithodora is a stunning little shrub, which, for years, I assumed was a perennial. I finally surrendered and brought some into my own garden. Its remarkable true-blue-to-almost-fluorescent hued flowers covering its deep green foliage captured my attention. Every spring I would notice it cascading down walls and flowering in gardens everywhere. Most likely, these shrubs were 'Grace Ward', a star performer in the Northwest. Now with this 2008 introduction of 'White Star', it makes Lithodora a megastar. The white runs down the center of each petal and subdues the brilliant blue petal margins, making it a perfect companion for spring bulbs, since it won't overpower the more pastel flowers.
Why did it take me so long to introduce them to my garden? It might be because I saw them everywhere, I didn't feel the need to see them in mine. No matter what my reasons were, the plants are perfectly suited for our cool summer region. Not only that, flower color is improved when growing in our naturally acidic soil. These drought tolerant shrubs will not thrive in alkaline conditions. Use this shrub for cascading affects down a wall or embankment, a ground cover, or in a rock garden where there is good drainage; soggy clay soils will mean failure.
In March of 2004, Danny Takao found this sport on a Lithodora 'Grace Ward' plant at Takao Nursery in Fresno, California. It has since been patented and was introduced to the trade in 2008.
The plants grow leggy as they become older; sheering them or pinching back new growth can help them keep their shape. Once they grow too woody, you may consider replacing them, much like how we replace older lavender plants when they lose their beautiful mounded shape.
The genus name comes from the Greek word lithos, meaning stone, and dorea, meaning gift. The epithet diffusa means loose, open or widely spreading.
Photographed at the Armitage garden, Pt. Gamble, Washington.