Sweet peas are the most romantic flower in the cutting garden — and the most demanding. They want deep soil, cool roots, and something to climb. Sow in root trainers in late winter (they need that cold period to germinate well) and plant out as soon as the ground can be worked. They hate heat: once summer arrives in earnest, they decline rapidly.
The reward is extraordinary: stems of intensely scented blooms from spring through early summer. Cut every single stem — the more you cut, the more they produce. Stop cutting or let them set seed and the whole plant shuts down.
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.