Black Knight Group is an erect perennial to 1.75m tall with lobed green leaves and spikes of semi-double, deep blue-purple flowers with black eyes in summer
Plant 'Black Knight' delphinium in an area that receives a daily dose of six hours or more of direct sunlight.
Grow delphiniums in a humusy soil that drains well. To ensure fertility, prepare the planting hole by mixing in compost. Delphiniums like neutral soil; if yours is acidic, amend with wood ash or lime to add alkalinity.
'Black Knight' delphinium has average water needs. Water young plants deeply to help develop strong roots. Keep the soil moist but not wet.
Temperature and Humidity
'Black Knight' delphiniums are part of the Pacific Series of cultivars, which are optimized for areas with cool to moderately warm summer climates. It performs much better where summertime heat waves are more the exception than the norm. In hot, humid climates, these perennials may live only two or three years.
Delphiniums need more fertilizer than you may be used to giving your perennials. Apply a balanced fertilizer every two to three weeks from the time the plants emerge from the earth to the time they stop flowering.