About
Lithodora zahnii, Zahn's gromwell, is an upright, many-branched, evergreen shrub to 30 cm with narrow, leathery, dark grey-green leaves. Small terminal clusters of blue or white flowers are produced all summer and sporadically in autumn. A rewarding and ornamental shrub for a sunny, very well-drained rock garden or raised bed.
About the genus
Lithodora are evergreen shrubs and sub-shrubs with five-lobed, blue or white flowers produced from early spring to summer. Excellent plants for sunny, well-drained rock gardens and raised beds.
Growing conditions
SunlightFull sun
Soil typeChalk, Loam, Sand
Soil pHAlkaline, Neutral
Soil moistureWell-drained
AspectWest-facing, South-facing
ExposureExposed
UK hardinessH4
Plant details
Plant typeShrubs, Alpine Rockery
HabitBushy
FoliageEvergreen
Height0.1-0.5 metres
Spread0.1-0.5 metres
Time to full height5-10 years
Suggested usesRock garden, City and courtyard gardens, Coastal, Cottage and informal garden, Gravel garden, Patio and container plants
Native toS Greece
Care notes
CultivationGrow in well-drained, preferably alkaline to neutral soil in full sun
PruningPruning group 8; or pruning group 10 after flowering
PropagationPropagate by semi-ripe cuttings in summer
Pest resistanceGenerally pest-free
Disease resistanceMay be susceptible to honey fungus in gardens where it is present but insufficient data to determine degree of susceptibility