Lavender is one of my favourite summer plants, adding a scented mediterranean feel to my garden for many weeks in the summer and acting as a magnet to bees, butterflies and moths. Following on from the allium ‘Purple Sensation’ and flowering alongside a variety of catmints and salvias, lavender keeps the purple notes flowing throughout my garden until the end of July. In winter I value its soft grey evergreen hummocks that give structure to otherwise empty beds.
The question is how best to look after lavender? All too often it ends up as a leggy mess with masses of dead wood and a few scraggy flowers.
My system is very simple. I buy a batch of tiny plug plants from Thompson & Morgan every spring to make sure that I can replace any losses and so that I can keep expanding my collection. Mature lavender plants are quite expensive, so this is a cost effective way of increasing my stocks. I know that I should be taking my own cuttings in summer from non flowering shoots and growing these on through the winter in a frost free place for free plants next year. Time is, however, limited and cuttings need regularly watering and potting on. It is easier to have them arrive in March and grow them on ready to plant out in June.
When the plugs have made small plants (usually by mid June), I choose a sunny spot that is not water logged in winter and plant them all out. After an initial watering lavender plants will grow on unattended and usually flower in their first season.
The key to keeping lavender plants young and fresh looking is to cut back the flower stems every August after the colour has faded. I cut back very lightly into the new leaf growth, shaping the plants as I go. On a large plant I will use my topiary shears from Burgon & Ball, but on smaller plants I find secataurs are easier and more accurate.
That’s it – the lavender is done for the year – no feeding or further attention is necessary and next summer the hummocks will be full of lovely purple flowers again.
I will often underplant lavender bushes with tulips or alliums to extend the season of interest and I have also used lavender under my espaliered fruit trees to provide colour in the summer.
French lavender I treat slightly differently. French lavender is instantly recognisable by the butterfly like petals on the flowers and is not as hardy as English Lavender. The only time I have successfully grown French Lavender in a flower bed was when we were living in London. In Suffolk it always rots over the winter, so I restrict it to pots these days and store the pots in a very sheltered spot during the winter months. The pots need regular watering throughout the summer months, but must not get water logged.
French Lavender has a longer flowering season than the English and will keep going for most of the summer if you regularly snip off the dying flower heads. Once it stops flowering I treat it in the same way as the English Lavender and cut back into the leaf growth by about an inch, shaping the plant as I go.