Cornflower is one of the most reliable hardy annuals in the cutting garden — the vivid true-blue of the classic variety is almost without equal among annuals, and the range extends through white, pink, lavender, burgundy, and bicolors. Direct sow very early — it germinates in cold soil and handles frost without complaint, and early sowing is essential before summer heat forces it to bolt.
For cutting gardens, succession sow every two weeks from late winter through early spring. Harvest when the central disc is just opening; the flowers shatter quickly if cut too late. Cornflower self-seeds freely and may naturalise in beds that suit it. A classic companion to poppies, nigella, and larkspur in loose cottage-style arrangements.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.