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Flowers

Delphinium Growing Guide: Planting, Care & Harvest

A tall border perennial with spires of blue or white flowers in early summer; stems need staking against wind.

Delphinium

Delphinium elatum

Growing calendar

Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.

Sow / plantGrowingFlowering

Guides

Common problems

Start from what you can see on the plant.

Pests and diseases (18)

Problems recorded for this plant, most serious first.

Bacterial Wilt

Disease

Leaves wilt while still green during the day and recover in the morning and evening; after a few days of this the plant dies. Cut the stem and stand it in water and a milky white bacterial ooze streams out in threads.

Powdery Mildew

Disease

White patches appear scattered on the upper leaf surface at first, then the whole leaf is coated in a white powder. Leaves later yellow, brown and die back, and reduced photosynthesis cuts growth and yield.

Late Blight

Disease

Dark green water-soaked lesions appear on the leaves and expand quickly into brown dead tissue. White mold forms on the underside and at the lesion edge, and dark brown lesions spread to stems and fruit.

Southern Blight

Disease

The stem rots at soil level and white silky mycelium spreads over the crown and the surrounding soil surface. Brown sclerotia the size of rapeseed then form and the plant wilts and dies rapidly.

Damping-off

Disease

The stem pinches in at soil level, turning water-soaked to brown and thin, and the seedling topples over. Infection before emergence makes the stand uneven with missing plants.

Bacterial Soft Rot

Disease

The crown or the head becomes water-soaked and soft, then collapses into a slimy mush. The rotting tissue gives off a distinctive foul odor.

Gray Mold

Disease

Water-soaked brown lesions form on flowers, fruit and leaves, densely covered by a fuzzy gray mold. Fruit rots and drops, and decay continues in storage after harvest.

Verticillium Wilt

Disease

Only one side of the lower leaves yellows and wilts, and the symptom moves up the plant. Stem vascular tissue turns pale brown and the plant dies without ever growing well.

Bacterial Spot

Disease

Small water-soaked spots appear on the leaves, later turning brown with yellowing around them. Fruit develops water-soaked or scabby spots from which rot spreads.

Leaf Spot

Disease

Small round brown to gray-white lesions appear on the lower leaves, the centers turning gray with tiny black specks. As they multiply the leaf yellows and drops early.

Downy Mildew

Disease

Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-purple mold in the matching spot underneath. Lesions merge, the leaves die back and the plant declines early.

Witches' BroomMosaic DiseaseFusarium Crown and Root RotFusarium Wilt and Damping-offBacterial Stem RotStem Rot WiltBrown Leaf Spot

Read next

Keep a growing history for Delphinium

Type the plant name, add the planting date, and take photos as it grows. Next season you will have your own dates for sowing, flowering, and harvest instead of a generic calendar.

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