Many of us have a love-hate relationship with lavender; on the one hand we appreciate its beauty and fragrance but then we experience its often short-lived nature and get frustrated. In either case there is no denying the breathtaking grandeur of a mass planting of Lavandula in full bloom and its other role as an important pollination plant becomes self-evident with the many bees and butterflies appreciating it right along with us. Regardless of its standing in your garden, lavender in flower continues to be a top seller at the garden centre and often heralds the arrival of summer. With that in mind I thought that I would provide you with an overview of the genus, including some tips on planting and pruning.
What Lavender Needs
Most of the hardy cultivated species are native to the Mediterranean and North Africa, so a full sun exposure is best with a minimum of 6 hours during the summer. Of equal importance is good drainage and poor to moderately fertile soils, as heavy clay tends to rot the root system during our wet winters and those with large amounts of compost or organic matter overfeed, resulting in floppy lavender. A light hand with the fertilizer (particularly nitrogen) is also beneficial, as this genus is used to lean, slightly alkaline soils (pH 6.7-7.2) – so you can add a little dolomite lime at planting time if you feel your beds are acidic. Pruning is another essential in order to keep your plants in good form, with a light contour cut in spring (along with the removal of any dead wood) followed by another just after the flowers have faded. The latter allows some of the essential oils to be left in the flower buds on the harvested stalks of either English Lavender or Lavandin for potpourri or culinary use. Spanish Lavender (Lavandula stoechas) blooms a bit more sporadically and you can deadhead individual flowers as they fade but the cardinal rule of pruning it is to never cut into old wood, as they seldom recover. Lavender is also extremely deer resistant and attracts a multitude of pollinators.
Lavandula angustifolia or English Lavender is the hardiest species at USDA zone 5 and in my opinion has the best longevity. It tends to be the most compact, averaging 24” high, with dwarf varieties such as ‘Blue Cushion’ growing 12-16” tall. The most common cultivars include ‘Hidcote’, ‘Munstead’, ‘Essence Purple’, ‘Loddon Blue’ and ‘SuperBlue’, although there are several colour options including white (‘Nana Alba’, Ellagance Snow’), pink (‘Rosea’, ‘Jean Davis’, ‘Hidcote Pink’), lilac (‘Melissa Lilac’) and even variegated foliage (‘Platinum Blonde’). For those of you on a budget, try growing ‘Lady’ from seed as it usually ends up blooming in its first year. Organically grown flower buds can be used for cooking, with my daughter’s lavender aioli served on barbeque lamb chops being one of my favourite dishes.
Lavandula stoechas has large showy blooms that much resemble a caterpillar’s body with a tufted wing or bract on top. They generally start blooming mid to late spring and will continue to do so sporadically throughout the summer with regular deadheading. It tends to grow a bit taller (24-30”) than English lavender and at USDA zone 7 can prove unreliable during cold winter weather. The most widely available varieties include ‘Otto Quast’, ‘Anouk’ and ‘Luxurious’ with colour variations including pink (‘Bandera Pink’, ‘Pink Summer’, ‘Strawberry Ruffles’), rose (‘Anouk Deep Rose’), white (‘Ballerina’, ‘White Anouk’) and even contrasting silver foliage (‘Silver Anouk’). The high camphor content means that Spanish lavender is inappropriate for culinary purposes but that also makes it even more deer resistant.