Lavandula angustifolia Ellagance Series
Lavender continues to be a popular perennial plant. Growers now have one more reason to be excited about producing lavandula: There is now an award-winning series with a range of flower colorations. Let me introduce you to the Ellagance series of lavandula from Kieft Seeds. There are three cultivars in the series: 'Ellagance Purple' with intense, purple-blue flowers; 'Ellagance Sky' with light violet-blue flowers; and 'Ellagance Ice' with white flowers and a light-blue blush.
Compared to popular cultivars of the recent past, such as 'Munstead Strain', the Ellagance series offers numerous improvements. Each cultivar in this series produces well-branched, bushy plants; provides early and prolific flowering; has unmatched uniformity; and delivers first-year flowering. These attributes combined with richness of flower colorations have earned each cultivar Fleuroselect awards: 'Ellagance Ice' earned the Quality Award in 2005, 'Ellagance Sky' won a Gold Medal in 2006 and 'Ellagance Purple' received the Fleuroselect Gold Medal in 2008.
The Ellagance series has outstanding garden performance and grows well in sunny locations throughout USDA Hardiness Zones 5 to 9 and AHS Heat Zones 9 to 1. They prefer hot, dry locations and do not like wet soils. Ellagance forms compact, bushy mounds of silver-green foliage reaching 12-14 inches tall by 10-12 inches wide and produces large, densely filled flower spikes from June to September. Lavenders are commonly used in containers, as border and mass plantings, and as cut or dried flowers. Additionally, lavandula is drought tolerant and resistant to deer and rabbit feeding.
The Ellagance series is propagated by seed. Another benefit of these cultivars is that they are available from Kieft Seeds as TunedSeeds, which eliminates the need for growers to stratify them during propagation and greatly improves the germination rate, decreases propagation time and improves crop uniformity.
Sow four to six seeds per cell in 288-cell or larger plug trays. Because light is required for germination, do not cover the seed with germination mix or vermiculite after sowing. The seed flats should be moistened and moved to a warm environment, where the temperatures can be maintained at 65-75¡ F for germination. Many growers use germination chambers during this stage to provide uniform moisture levels and temperatures. The media should be kept moist but not saturated.
Germination begins within a few days and takes up to 14 days to be completed. Following germination, reduce the moisture levels somewhat, allowing the growing medium to dry out slightly before watering to help promote rooting. Fertilizers can be applied once the true leaves are present, applying 100-ppm nitrogen every third irrigation or 50 ppm with every irrigation, using a balanced, water-soluble source. When produced at temperatures averaging 68¡ F, they are usually ready for transplanting in eight to nine weeks.
For container production, lavenders are suitable for quart- to gallon-size pots. When planting large containers, such as 1-gallon pots, I recommend planting at least two plugs per container to properly fill out the pot.
Lavenders perform best when they are grown in a moist, well-drained medium with a slightly acidic pH, 5.8-6.2. Most commercially available peat- or bark-based growing mixes work well, provided there is adequate drainage. When planting, the plugs should be planted so the original soil line of the plug is even with the surface of the growing medium of the new container. The best quality is achieved when plants are grown in full sun or in greenhouses with high light intensities, 2,500 to 3,500 foot-candles is sufficient.
They require an average to slightly below average amount of irrigation as they do not tolerate overly wet or dry conditions. When wet conditions persist for extended periods, lavenders are very susceptible to root rot. When irrigation is necessary, water them thoroughly then allow the soil to dry slightly between waterings.
Lavandula are light feeders. Growers can apply water-soluble fertilizers as needed using 100- to 150-ppm nitrogen or constant liquid fertilization at 50- to 75-ppm nitrogen with every irrigation. Controlled-release fertilizers are commonly used by incorporating 0.75 to 1.0 pounds of elemental nitrogen per cubic yard of growing mix prior to potting.
With their compact growing habit, the Ellagance series usually does not require height control. There is often the need to control stem elongation during early season production in greenhouses where the light levels are low and relative humidity is high, or when plants are being grown pot-to-pot. In these circumstances, foliar sprays of uniconazole (Concise or Sumagic) at 5 ppm, applying one to two applications seven days apart, should provide sufficient control. Plant growth regulators containing daminozide (B-Nine or Dazide) at 2,500 ppm or paclobutrazol (Bonzi, Paczol or Piccolo) at 30 ppm will also deliver satisfactory results.
Insects and Diseases
Lavender can generally be grown without significant damage from insects and diseases. Numerous insect pests may be observed feeding on lavandula including aphids, caterpillars, four-lined plant bugs, leafhoppers, spider mites and whiteflies. Of these insect pests, aphids and whiteflies are usually the most problematic.
The diseases most likely to infect them include Botrytis, Phytophthora, Pythium, Rhizoctonia, Septoria and Xanthomonas. The most common disease is Phytophthora; it starts in the crown and appears as an aerial blight (browning leaves moving up the stem). Phytophthora can be
managed with adequate spacing between the plants, sufficient air movement, controlling the humidity, and avoiding overly wet growing conditions. Effective fungicides for controlling Phytophthora on lavender include, Aliette, Compass, Heritage, Stature, Subdue MAXX, Terrazole and Truban.
Routine scouting is useful and recommended to detect insect pests and plant diseases early, allowing the appropriate control strategies to be implemented before significant crop injury or mortality occurs.
Many growers produce non-blooming lavender and market them as foliage items. When transplanting from 72-cell plugs, it will take eight to 11 weeks to produce nonflowering 1-gallon containers of marketable size. The Ellagance series is easy to force into bloom, and is most commonly produced for mid-spring and early-summer sales. This series is also suitable for production and marketing as blooming houseplants.
As mentioned above, Ellagance cultivars will flower in the first year and do not require a bulking period in the fall or vernalization in order for them to produce full, flowering and high-quality plants. Fresh plugs can be transplanted directly into the final container. Although they will flower under shorter photoperiods, they bloom best (with more uniform and consistent flowering) when they are grown under long days. During naturally short day lengths, I recommend providing photoperiods of 16 hours by extending the day if necessary, or using a four-hour night interruption during the middle of the night, providing a minimum of 10 foot-candles of light at plant level.
When fresh plugs are transplanted in the early spring, it will take 12 to 14 weeks to produce flowering plants of 'Ellagance Purple' and 'Ellagance Sky' and 15 to 16 weeks for 'Ellagance Ice' when they are grown with 24-hour average temperatures of 64¡ F and under long days.
For early spring sales, growers can plant the Ellagance series in the late summer or early fall and over-winter them in the final container. In the late winter or early spring, lavender can be grown under any photoperiod (long days recommended) and will flower in approximately eight to 10 weeks when they are grown at 64-68¡ F.
TunedSeeds of the Ellagance series are available from Kieft Seeds. Plugs can be acquired from C. Raker & Sons, Inc. (www.raker.com), Pacific Plug and Liner (www.ppandl.com), Swift Greenhouses, Inc. (www.swiftgreenhouses.com) or from several reputable plug producers and plant brokers.