English lavender (Lavandula augustifolia) remains the classic lavender to grow for scent, beauty and even for cooking. English lavenders tolerate cold winters better than French, Spanish and spike lavenders or the related lavandins. The flower colors vary according to the English Lavender cultivar; deep purples and blues retain their colors upon drying better than pinks and whites.
Without question, the more sunlight you give to lavender, the happier it will be. These sun-loving herbs require at least six hours of sunlight a day. Place lavender and other Mediterranean herbs (thyme, marjoram and oregano) in the sunniest part of your garden or patio. Make sure the site isn’t in an area which bogs down during rainy seasons; lavender is vulnerable to root rot and fungal disease.
Well-drained soil remains the best chance of keeping lavenders from developing fungal disease. Add sand or fine gravel to normal to clay soils, or consider growing it in a raised bed. Test your soil’s pH level with a home kit or by sending a sample to your local extension service. Lavenders grow best in slightly alkaline soil, so you should aim for a pH level of 6.5 to 8.2, according to “Herb Companion” magazine. Mulching with oyster shells or marble chips add the necessary lime to the soil that raised alkalinity. Digging wood ash or garden lime into the soil prior to planting also raises the pH level.
Pruning and Harvesting
Regular pruning enables the small shrubs to develop a more compact shape. When first planting lavender seedlings, cut off the flower spikes to encourage bushy foliage and better future floral production. In subsequent years, cut the branches back by a third before the plants flower. Cutting new growth later in the season will not only yield armfuls of fragrant flowers, but help new branches develop at the base of the plant. For the best scent for dried arrangements and potpourri, harvest the flowers during dry weather, in the morning after the dew has dried. “Fine Gardening” magazine notes that harvesting the branches when they are just about to flower results in the most intense colors once they dry.
Each climate represents its own special challenge to the lavender grower. Northern growers need herbs capable of surviving cold winters. As a group, English lavenders are the hardiest of the lavenders for northern gardens, but “Hidecote” is especially hardy. Southeastern gardeners need a lavender which can stand up to heat and humidity. “Munstead” represents a good choice for those regions.
Because English lavender is only reliably tolerant to Zone 5, growers north of that region opt to either treat the flowering herb as an annual or to grow it in pots and bring them in for the winter. Lavender can prosper as an indoor herb, but does best a few inches away from a fluorescent bulb or grow light. For northern gardeners determined to grow lavender outside as a perennial, consider placing the herb in front of a cement foundation or in a rock garden. The heat from the nearby heat sources help protect lavender in the winter.
For growers in many southern states, humidity is lavender’s natural enemy. Strike back by growing the herbs in containers filled with potting soil or by using raised beds. Giving the plants plenty of space will also promote the air circulation required for beating fungus and mildew. Remove leaves or whole plants with spots, mildew or fungus on them. Don't weed or prune during wet weather; this practice spreads disease among plants.