April 2003

Lavandula angustifolia ‘Hidcote Superior’ By Paul Pilon

Lavender ‘Hidcote Superior’ is an improved version of the very popular cultivar lavender ‘Hidcote’. The improvements over its predecessor include enhanced uniformity, consistent quality and improved flower power. This cultivar of English Lavender remains compact and is very suitable for container production or in border plantings. Hidcote Superior naturally blooms from June to September, bearing numerous deep violet blue flowering spikes.

Introduced to the marketplace in 2001, Hidcote Superior, like most lavender cultivars, is hardy in Zones 5-9 and grows best under full-sun conditions. Flowering plants sell well at retail; however, with its whitish-gray foliage, lavenders usually create a high sell thru even when they are not in bloom. Besides being a useful plant in landscapes, lavenders have been used throughout the years for aromatherapy and as a useful herb. In fact, the genus name lavandula is derived from the latin word lavo, which translates to “I wash,” referring to an aromatic wash of lavender water once used.

Propagation

Hidcote Superior is most commonly propagated from seed but can be propagated vegetatively by cuttings. To increase the germination rate and decrease the germination time, I have found it most beneficial to sow the seed into the plug trays and place them into a cooler with temperatures of 38-40¡ F for 4-6 weeks, then move them to a germination chamber or a greenhouse to finish the germination process. Propagating Hidcote Superior in this manner will take approximately 11 weeks to finish a 220-size plug after the cooling period.

Jelitto Perennial Seeds has developed a procedure for eliminating the seed dormancy of many perennial cold germinators, allowing for quick and uniform germination without the need to provide a cold treatment. ç

Their patented process is offered to the industry as Jelitto Gold Nugget Seed and currently includes more than 100 varieties of perennials, including Hidcote Superior. This pretreated seed eliminates the four weeks of cold recommended above and reduces the finish time from 11 weeks down to eight weeks for a 220-size plug, substantially cutting the total time necessary to produce Hidcote Superior from traditional, untreated seed.

Production

Lavender performs best when produced in a well-drained, porous soil. When moist or wet conditions occur, it is very susceptible to root rots. It is a light feeder and grows well under a constant liquid fertilizer program with fertilizer rates of 50-75 parts per million (ppm) nitrate or by incorporating a controlled release fertilizer at a rate equivalent to 3?4 pound of nitrogen per yard of growing medium. The pH should be maintained between 5.8-6.2. Water thoroughly as needed, allowing the soil to dry between waterings. The best quality is achieved when plants are grown in full sun or in greenhouses with high light intensities.

Hidcote Superior is a fairly compact plant, and when grown at adequate spacing and light levels, height control is seldom necessary. However, controlling stem elongation may be necessary when grown in a greenhouse in the early spring. When necessary, I recommend applying Sumagic at a minimum rate of 5 ppm (the rate will vary with location, this is a northern rate). Two applications, seven days apart should provide adequate control. Before applying these chemicals, height can often be effectively controlled by providing adequate spacing between the plants and by withholding water and nutrients.

Rhizoctonia is the most common disease of lavender and may occur at anytime throughout the production cycle. Managing the environment by reducing humidity and following sound irrigation practices is the best method of controlling the occurrence of Rhizoctonia. If chemical control is necessary, there are several chemicals on the market, such as Medallion 50W, Terrachlor 75WP, Heritage and Contrast 70WSP, that provide excellent control of Rhizoctonia when applied as drenches.

As with diseases, there are not many insects that cause significant amounts of damage to lavender. Occasional outbreaks of aphids and whiteflies may be observed and can usually be eliminated by applying a preventative drench of Marathon 60WP two weeks after transplanting.

For container production, Hidcote Superior is suitable for production in 1-quart to 1-gal. containers. For 1-gal. production, I recommend planting three 200-cell plugs into each pot. When grown at 65¡ F, it will take about eight weeks to produce a plant of salable size without bloom. Blooming plants will occur when they reach the right maturity, are grown under the proper photoperiod or by following the recommendations listed below.

Forcing

To improve marketability, Hidcote Superior can be forced to bloom throughout the year. The production of lavenders as houseplants is a fairly new market phenomenon that growers should take advantage of. Consumers use the plants indoors until the initial flush of flowers has died and then outdoors in the landscape where another flush of flowers can be enjoyed later in the summer months and for several years thereafter.

Successful forcing involves following a few key guidelines. I recommend beginning the forcing process using fairly large plant material consisting of at least 40 leaves. Smaller plant material will most often provide less uniformity, less flowers per plant and decreased percentage of flowering plants. I have had the best results when the lavender is cooled for at least 10 weeks prior to forcing, this provides for more uniform and faster flowering. Un-cooled plants will still flower, but they will be more inconsistent and will take considerably longer to reach flowering. Once the cold period is achieved, force Hidcote Superior under long day conditions by providing 16 hours of light or a four-hour night interruption until the flower buds are visible. Growers should ensure a minimum light intensity of 10 foot-candles. From the start of forcing, it will take about 11 weeks to reach flowering at 60¡ F or eight weeks at 68¡ F.

Availability

Hidcote Superior is exclusively available as seed from Jelitto Perennial Seeds as either regular seed or Jelitto Gold Nugget Seed. Plugs, or finished containers can be purchased from many reputable plug producers or finished growers throughout the country.