Lavender is very easy to grow. They need an open sunny position in well drained but fertile soil, however they can usually cope with partial shade so long as the soil is good enough. Lavender is best planted in spring, although since it is usually supplied in pots or plugs it can be planted any time of year (but do avoid doing this over winter if possible)
Lavender does need some annual maintenance, but this is simple and quick. Each spring trim to to shape, and then before the autumn frosts and after the plant has finished flowering trip back to the leaves with a pair of shears (but avoid cutting into the mature wood as this will not grow back).
The flowers are best harvested just as they open, and can be dried by hanging in small bunches.
It can be grown from seed, but often does not grow true to form, so Lavender is best propagated from cuttings. Softwood cuttings can be taken in spring, or semi hardwood cuttings can be taken in summer, putting the cuttings in pots of compost and grit mix.
Keep them covered over winter after they have rooted (ideally in an unheated greenhouse or cold frame, and then plant out the following spring.
They can also be cultivated quite successfully by layering.
There are far too many varieties of lavender to name them all here; they come in different sizes, and different coloured flowers ranging from white, pink to deep purple. Look in the catalogues and select the varieties that best match your needs.
It is not a popular culinary herb, however I have seen some great recipes for lavender biscuits, and seen it used to flavour all manner of dishes with some great results. I particularly like lavender jelly (serve this with a bit of lamb, or just spread on toast!)
More common however are its uses in crafts or in cosmetics. Flowers can be used in potpourri or herb pillows, and I am told that if you pin some to your clothes it will discourage flies. It is also great for use in soaps, or do what the Romans did and add some to your bathwater.