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Lithodora spp.
lithodora
Southern and western Europe, North Africa, and western Asia
Overview
Lithodora spp. is a small genus of evergreen subshrubs in the borage family, Boraginaceae, native to southern and western Europe, North Africa, and western Asia. Plants are low, spreading to mounded, 4-24 inches (10-60 cm) tall and wider than tall, with wiry, often bristly stems and small, narrow, dark-green leaves with rolled-under margins. From late spring through summer, the stems carry clusters of funnel-shaped flowers, most often a deep blue, though some species and forms are violet, pink, or white. L. diffusa is a low, mat-forming species widely grown for its blue flowers, while L. zahnii and others are more upright. The genus grows in full sun in light, sharply drained soils, and most species need acidic to neutral ground, becoming chlorotic and weak on alkaline soils. Plants tolerate heat and drought once established but rot in heavy, wet, or poorly drained soil. Hardiness varies by species, with the more cold-tolerant types reliable to about USDA zone 6. Foliage can scorch in cold, drying winter winds in exposed sites.
Native Range
Lithodora spp. species are native to southern and western Europe, the Mediterranean region, North Africa, and western Asia, where they grow on rocky slopes, open scrub, woodland edges, and sandy or gravelly ground, often on acidic soils.Suggested Uses
Grown in rock gardens, raised beds, gravel gardens, dry stone walls, and at the front of sunny borders, and used as a trailing groundcover over banks and in containers. The mat-forming blue-flowered species are used to spill over edges and walls in acidic, free-draining sites.How to Identify
Appearance
Size & Dimensions
Height4" - 2'
Width/Spread1' - 3'
Bloom Information
Flowering occurs from late spring through summer, generally May to August, with the heaviest flush in early summer. Funnel-shaped flowers, usually deep blue, open in clusters at the stem tips over many weeks. Sporadic later flowers can appear into autumn in mild conditions.
Detailed Descriptions
Flower Description
Deep blue, sometimes violet, pink, or whiteFoliage Description
Dark greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Lithodora spp. grows in full sun in light, sharply drained, gritty soil. Most species need acidic to neutral conditions and develop yellowing leaves and weak growth on alkaline or limey soils. Established plants tolerate heat and drought, but heavy, wet, or poorly drained soil leads to root rot. A position with good air movement reduces winter foliage scorch. The more cold-tolerant species are hardy to about USDA zone 6, while others need milder conditions. A gritty mulch keeps the crown dry and sets off the trailing stems.Pruning
A light trim after the main flush keeps plants compact and encourages fresh growth and repeat flowers. Only soft growth is cut, as plants respond poorly to hard pruning into old wood. Winter-damaged shoots are removed in spring.Pruning Schedule
summer
Container Growing
✓ Suitable for container growing
Minimum container size: 2 gallons