How to Fertilize penstemon 'Southgate Gem'?
Balanced perennial feed every four weeks from spring through summer

penstemon 'Southgate Gem' · Penstemon 'Southgate Gem'
Grow in fertile, moist but well-drained soil in full sun in a position sheltered from frosts and drying winds; in autumn, cut plants down by two-thirds of their height and protect with a dry mulch; for more advice, see penstemon cultivation
Balanced perennial feed every four weeks from spring through summer