No fault of yours, but this is the fifth Delphinium I have planted in the past three summers and it didn’t make it past a week in the ground. Must be something in my soil, because everything else is growing beautifully. The first year, two flowered and didn’t return. Second and this year they just died within a short period. Maybe they don’t like Long Island.
Answer: Dear Long Islander, Growing Delphiniums can be a challenge even for the advanced gardener. They are a finicky, short-lived perennial with flower stalks up to six feet tall sporting blooms ranging from midnight to royal to sky blue, and even some in pinks and white. They are often called Larkspur, a member of the Ranunculaceae family. They prefer a climate that has cool and moist summers, not the hot, dry summers we have been experiencing lately. The soil needs to be moist, well-drained, and not heavy clay, and they want full sun to light shade. It’s often best to put them in a raised bed. When planting them, dig a hole that is at least twice the size of the root ball, and mix in compost to help keep the soil well drained. If you can get them established, then you will want to cut the stems back after the killing frost to an inch or so above the soil line. Divide plants every three to four years. Good luck with your flowers.