Leucanthemum x superbum ‘Becky’
Leucanthemum ‘Becky’ is quickly becoming one of the most common varieties of Shasta daisy in commercial production today. This cultivar has many distinguishing characteristics, such as shiny, deep-green leaves that hold up well in heat and humidity; strong stems, which prevent lodging; and hardiness in both Southern and Northern states. This long-lived variety has gained so much attention that the Perennial Plant Association has selected Leucanthemum Becky as the 2003 Perennial Plant of the Year.
Becky reaches three feet tall and produces large, 3-inch, single white flowers with yellow centers from June-August. When growers cut back the plants during the growing season, or deadhead them, I have seen flowering into the month of October. The foliage is always attractive and will remain evergreen in Southern states. It is both heat- and cold-hardy in Zones 4-9 and can be grown under full sun to partial shade in an average to dry soil. This Shasta daisy performs well as a cut flower and attracts butterflies in the garden. For compact plant growth, cut back foliage before flower buds are visible. To encourage re-flowering, cut them back after the initial flush of bloom is finished. For commercial production, this vegetatively propagated variety is most often finished in 1-gallon containers.
Becky is most commonly vegetatively propagated by tip cuttings and division. Cuttings should be taken from non-flowering shoots and will root easily in about 3-4 weeks under a light misting regime. It is very common for Becky to appear wilted on the misting bench. I usually do not like to see flaccid plants during the propagation stage but have not experienced significant plant losses due to the wilt. Taking cuttings with a smaller leaf size does seem to reduce the wilting somewhat. Once the cuttings form roots, usually 10-14 days after sticking, the daily wilting will stop. To accelerate rooting and improve uniformity, dip the base of the cuttings in a 1,500-ppm IBA rooting hormone. For ideal rooting, maintain soil temperatures of 70-75º F, relative humidity of 85-90 percent and photoperiods of 13 hours or less (short days).
Compared to the Shasta daisy varieties propagated by seed, Becky is very uniform and reliable. Plugs acquired from growers range in size from a 128-cell to a 3-inch liner. Divisions can be taken in the spring or fall.
Leucanthemum Becky performs best in a moist, well-drained medium with a slightly acidic to neutral pH: 5.8-6.8. It is a moderate feeder and performs best when either a constant liquid fertilization program is used, feeding at rates of 50-100 ppm nitrate, or a controlled-release fertilizer is incorporated at a rate equivalent to 1-1.5 pounds of nitrogen per yard of growing medium. Plants grown under lower fertility regimes will most likely be shorter. Becky requires frequent and thorough watering. They can tolerate and fully recover from short periods of drought stress; however, prolonged periods of drought stress may cause the leaf margins to turn necrotic. Plants grown too dry will often be shorter, exhibit a delay in flowering and produce fewer flowers. Non-flowering plants for spring sales should be grown at a minimum of 50° F.
To maintain vegetative growth, Becky stock plants should remain under short days. In most parts of the country this requires pulling a black cloth over the production area from about March 15-September 15 to shorten the day. Production temperatures should be 64-68° F. Following this regime would allow cuttings to be taken every 4-5 weeks. Most growers will not be able to provide short days and maintain temperatures this low. Cuttings can still be taken from plants grown under long days; however, there will be fewer cuttings available per plant, and most frequently small flower buds are present. I have had good success rooting cuttings with some small buds on them.
Becky is relatively disease-free and under normal growing conditions does not usually require the use of fungicides. Aphids, whiteflies and thrips infrequently will become problematic. Occasionally, I have observed plants with galls or very numerous small shoots on the crown near the soil line. This shoot proliferation and formation of galls are caused by the bacterium Agrobacterium tumefaciens. Since there is no known treatment for plants with these symptoms, the infected plants should immediately be discarded and the area sanitized to prevent spreading to uninfected areas. Unlike many cultivars of Shasta daisy, it does not appear to be as sensitive to insecticides and fungicides. However, use caution when applying these chemicals. Symptoms of chemical sensitivity include leaf burn, chlorosis and with many cultivars, plant death.
Height control is often necessary to produce a high-quality product under greenhouse conditions. Providing adequate spacing between the plants will reduce plant stretch caused by competition. The height can also be reduced by withholding water and nutrients. Under certain growing conditions or under high plant densities, it may be necessary to use chemical plant growth regulators. Depending on your geographic location, apply Sumagic at 5-10 ppm or Bonzi at 30-60 ppm. It will usually require 2-3 applications at 7-day intervals to provide adequate height control. Begin the applications as the flower stalks start to elongate.
Becky can be forced into bloom out of season by following a few guidelines. Generally, it is recommended to cool (vernalize) plugs or small containers of Becky for a minimum of six weeks at 40° F. Then provide photoperiods (daylength) of 16 hours by extending the day if necessary, or use a 4-hour night interruption during the middle of the night, providing a minimum of 10 foot-candles of light at plant level. Becky will flower under long days regardless of the vernalization time; however, providing a cold period will produce flowering plants more uniformly and with more total flowers. The time to flower depends on the temperature the plants are grown at. Plants grown at 60° F will flower in about 10 weeks, while plants grown at 72° F will flower in as little as six weeks. For the largest flower size, most flowers and shorter plants grow at cooler temperatures.
Becky is widely available as a plug, bareroot or finished container from many reputable companies across the country.