Blue flax is one of the most delicate-looking plants in the cutting garden — pools of sky-blue five-petalled flowers on wiry stems that move in the slightest breeze, each bloom lasting only one day but replaced continuously for months. The overall effect is of mist or scattered blue light. Easy from direct sowing, drought tolerant, and reliably perennial in Zone 4.
As a cut flower, blue flax is a filler and texture plant — the slender stems and tiny blooms add lightness to any arrangement. Cut in the morning for best vase life. Direct sow in autumn or early spring; it germinates readily in cool soil.
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.
Crown Rot
Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.
Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.
Rust
Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.
Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.
Aphids
Aphididae →Clusters of small soft insects on new growth and flower buds.
Knock off with a strong jet of water. Ladybirds and lacewings are natural predators. Insecticidal soap as last resort.