Numerous cultivars available. Some include:
Environmental Damage
Fungal Disease
Insect Damage
Insect Relative Damage
Additional pests and problems that may affect this plant:
Crown rot, powdery mildew, pythium, rhizoctonia, leaf miners, aphids, mites, cut wormsD. x elatum are the most spectacular but also the hardest to grow in the Midwest as it prefers cooler summer conditions for best growth. Tends to be short lived (2-3 years). Don't plant to deep.
D. x belladonna is the delphinium of choice for the Midwest as it does better in the heat and is longer lived. Not as spectacular a bloom however.