Lemon thyme combines the warmth of thyme with a true lemon scent, which makes it the thyme for fish, chicken and lemon-forward desserts, and for a pot by the kitchen door where you brush it in passing. The gold-edged form 'Aureus' is as ornamental as it is useful. Culture is identical to English thyme: full sun, lean soil and sharp drainage.
Plant it 12 inches apart in spring, in gritty or sandy ground, and water only until it is established; wet feet in winter are what kill thyme, not cold. Harvest sprigs before it flowers for the strongest flavour, and trim the plant lightly after the pink flowers fade in midsummer to keep it compact. It does well in containers and troughs, which also give it the drainage it wants.
The flowers are small but bees cover them. Plants get woody after three or four years, so take cuttings or layer a low stem in summer to keep a young plant coming. In zone 5 it benefits from a winter mulch of evergreen boughs; deer and rabbits leave it alone.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.
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.
Botrytis (grey mould)
Grey fuzzy mould on petals and stems, worst in cool wet conditions.
Remove affected parts immediately. Improve air circulation. Avoid overhead watering. Apply copper fungicide if severe.