Lithodora diffusa ‘Grace Ward’

Published February 09, 2016

This groundcover is truly a gem in the landscape with its sapphire-colored flowers that appear in spring and last through the summer. The true-blue flowers (no purples disguised as blue in this plant) pair well with hostas, heucheras and painted ferns. Market this plant for use in rock gardens, for retaining walls or along slopes.

It forms a dark-green mat that can take light foot traffic, and it’s not an aggressive plant. It plays nice in the landscape without being too pushy.

Why grow Lithodora diffusa ‘Grace Ward’?

True blue flower color.
Evergreen where hardy.
Attracts butterflies.
Deer resistant.

Specifics

Description: Azure colored, funnel-shaped flowers appear in mid-spring and persist through late summer, depending on the region. ‘Grace Ward’ forms a mat of dark green foliage that grows 4 to 6 inches tall and spreads 3 to 6 feet. The one-inch leaves are narrow and hairy.

Hardiness: USDA Hardiness Zones 6-9.

In the landscape: Although it’s the ideal rock garden plant, it also works in a Mediterranean style landscape. It grows best in full sun, but will need some light shade in the hotter climates. Over time, as the plant spreads, the center of the mat can die off. At this point it’s best to the prune the entire plant severely to encourage new growth. L. diffusa must have a well-drained, acidic soil to thrive – it will not survive in heavy clay soils. In colder regions this plant will benefit from a light covering of evergreen boughs as soon as the soil is frozen.

Fun facts: This plant was formerly known as Lithospermum diffusum by Mariano Lagasca y Segura, 1776-1839 of Spain, and many contemporary references still consider this a synonym for L. diffusa. This and other plants were separated from that genus and reclassified in a whole new genus created for them by botanist Ivan Murray Johnston of the Arnold Arboretum at Harvard University.

Sources: Washington State University, Heritage Perennials, Monrovia

Rising tide

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