Thymus vulgaris
A low, woody Mediterranean perennial for the sunniest, best-drained spot you have. Start from a plant or a rooted piece rather than seed, cut it just before it flowers and trim it after, and replace it every three or four years when the middle goes bare.
Hardy in zones 5a–9b
Pollinated by insects — fruit sets only where bees and other pollinators reach the flowers. Grown for leaves, so pollination does not matter for the harvest. The small pink to lilac flowers are heavily worked by bees; leave a few stems to flower after you have cut what you need. Seed-raised plants vary, which is why named thymes are grown from cuttings or division.
Full sun; thyme in shade grows thin, floppy and mild.
Water new plants until they root in, then only in long dry spells; thyme dies of wet far more often than of drought.
A light, gritty, free-draining soil that stays on the dry side; poor soil is fine.
Very little: established thyme needs no feeding, and rich soil gives soft, mild growth.
No support; cut it just before flowering, trim after, and keep it out of the old bare wood.
Snip sprigs any time once the plant is growing well; for drying, cut just as the flower buds form.
Leaves
Ready 60–90 days from sowing
Sprigs once the plant is growing strongly; flower buds formed but not yet open for the main drying cut.
Harvest every year — a perennial
Keeps 180–365 days — cool and dark
Dried, whole, airtight. From a bought plant, light picking in the first summer.
A young plant or rooted piece settling in; water it until it is growing away, then leave it alone.
A spreading low bush of wiry leafy stems; pick sprigs freely.
Short stems carry tight clusters of tiny pink to lilac flowers; take the main cut as the buds form.
Sits through winter as a low evergreen bush; cold is fine, wet is not.
English and French thyme
The standard culinary thymes. French is narrow-leaved, upright and sweeter; English is broader-leaved, lower and spreading. Hardy and long-lived as thymes go; grow both from cuttings.
Lemon and citrus thymes
Thymus × citriodorus and relatives: lemon, lime and orange scents, often golden or variegated. Hardiness varies by variety, so check the label and give the sharpest drainage you can.
Creeping and woolly thyme
Mat-forming mother-of-thyme, wild and woolly thymes, a few centimetres tall, for paving and rock gardens. Woolly and low types struggle in heat and humidity (Clemson).
Stages affected: Vegetative · Flowering
Mites under 1.3 mm that feed on the undersides of leaves and spin fine webbing. Populations explode in hot dusty dry conditions and after broad-spectrum sprays kill their predators.
Stages affected: Flowering · At planting
A soil fungus present in most gardens that rots young stems at the soil line and the roots below, and in humid weather spreads as brown threads across dense, low foliage. It attacks cuttings, seedlings and new transplants of many crops, and low, mat-forming herbs such as thyme. Unlike the water moulds it does not need waterlogged soil.
Stages affected: Flowering · Dormant
The soft grey fuzz that turns ripe strawberries, raspberries, grapes and tomatoes to mush within a day of warm wet weather, and rots the crowded centres of low herbs such as thyme. One fungus with hundreds of hosts, living on dead plant material everywhere; on fruit it infects the flowers at bloom and waits in the green fruit until it ripens. Wet tissue, crowded plants and overripe or damaged growth are what it needs.
Stages affected: Vegetative · Flowering
Small soft-bodied sap-sucking insects that cluster on the softest new growth. They reproduce extremely fast in warm weather and are the main insect vector of plant viruses in the garden.
Stages affected: At planting
The caterpillars of several drab night-flying moths. They live at the soil surface and chew through the stems of young plants at ground level, so you almost always find the damage before you find the caterpillar.