Tarragon is a half-hardy perennial (tender, but grows from year to year) that is very useful in a wide range of dishes and is a great partner for tomatoes, chicken and eggs. An attractive plant it is ideal for a warm sheltered spot in well drained soil, but being half hardy is best grown in containers in most areas so that it can be given some protection from frost during the winter.
There are two types, French tarragon and Russian tarragon and of the two, French tarragon has the better flavour and is the one to seek out. However, you will have to buy a plant from your garden centre or a herb specialist to get you started as the French version does not produce viable seeds. Its Russian cousin produces a bigger crop of leaves, is hardier and so more likely to survive the winter and can be grown from seed.
The seeds of Russian tarragon are sown in the spring and both sorts can be propagated once established either by taking root cuttings or division (splitting a clump into smaller portions). Plants may reach 1m (3ft 3in) tall. Although perennial, it is best to treat Russian tarragon as an annual and to sow fresh seeds each year since plants soon become straggly. However if you wish to keep your plant through the winter, spread a thick mulch around the roots in the autumn to help insulate them from the cold. In the case of French tarragon, take some cuttings in late summer and root them in time for the winter.
Grow them on in a frost-free place and use them to replace the parents. Cuttings root very easily in a 50:50 mix of peat or coir and sharp sand, or you can dib them into cuttings compost in cell trays, one cutting per cell. For sure-fire success, give them a little heat in a propagator set to 15C (60F). Cut regularly to keep the plants bushy and to avoid straggly growth.
Growing in pots
Tarragon will grow very well in containers and can be planted using any good multi-purpose compost. Place the container on a sunny patio out of cold winds and again cut regularly to keep plants bushy. Feed occasionally with a liquid fertiliser such as a tomato food to maintain healthy growth. Moving your pot into a cold greenhouse or polytunnel in late summer/early autumn will help to protect growth and keep the harvest going for a little longer.
Tarragon is best picked fresh, but can be frozen in small quantities in freezer bags to keep supplies going through the winter months.