Jacob's ladder 'Polemonium caeruleum', is a lovely clump-forming perennial, requiring little maintenance. In early summer it produces bell-shaped flowers. Plants can be propagated by sowing seed in autumn or spring, or by dividing plants in spring. Polemonium caeruleum 'White Pearl' forms a low mound of cream-edged green leaves. In mid-to late spring, clusters of brilliant white flowers hang on upright stems. It's ideal for using as ground cover at the front of shady borders and edging paths. For best results, grow 'White Pearl' in moist but well-drained soil, in partial shade. Cut back after flowering to encourage a second flush of blooms. In autumn cut back again to ground level.