How to Water Californian lilac 'A.T. Johnson'?
Moderate regular watering, avoid prolonged drought and stagnant waterlogging

Californian lilac 'A.T. Johnson' · Ceanothus 'A.T. Johnson'
Grow in fertile, well-drained soil in full sun with shelter from strong, cold winds. Lime tolerant but may become chlorotic on shallow chalk soils. See ceanothus cultivation
Moderate regular watering, avoid prolonged drought and stagnant waterlogging