Sorrel is a hardy perennial herb grown for its tart, lemony leaves used in soups, sauces, and salads. It is one of the earliest greens available in spring and tolerates cold well, making it useful when little else is up in upstate New York gardens.
Plant it once and it returns each year. Harvest leaves young for the best flavor and texture. Remove flower stalks as they appear to keep the plant producing leaves rather than going to seed. Divide established clumps every 3–4 years to maintain vigor.
Dock Leaf Rust
Bright orange to brown pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavily infected leaves yellow and die back.
Remove and destroy infected leaves. Since dock is a weed, full removal of the plant is the most effective control. Avoid composting infected material.
Aphids
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.
Downy mildew
Yellowing on top of leaves with grey-purple fuzz underneath. Spreads rapidly in humid conditions.
Remove affected leaves. Improve air circulation. Avoid overhead watering. Copper spray as preventive.