Myosotis sylvatica ‘Rosylva’

April 9, 2008 - 12:37

Myosotis sylvatica is a biennial that is often produced as an annual and marketed alongside bedding plants. It is a familiar plant that has been used for years in gardens as a border plant or flowering groundcover. Commercially, growers most often produce this cool-season, floriferous perennial for early spring programs. Like many cool-season plants, myosotis does not tolerate the extreme summer heat of much of the United States or the severe Northern winters. Despite its seemingly fragile nature, many growers and landscapers use myosotis as a welcome source of spring color in the landscape. As the common name suggests, forget-me-not symbolizes everlasting friendship, remembrance and eternal love.

‘Rosylva’ is a reliable, vigorous cultivar in the Sylva series from Benary Seeds. All three cultivars (‘Bluesylva’, ‘Rosylva’ and ‘Snowsylva’) in this series have received Fleuroselect awards in Europe for their desirable attributes and performance. ‘Bluesylva’ and ‘Snowsylva’ have been named Fleuroselect Quality Mark winners, and ‘Rosylva’ received a Fleuroselect Gold Medal.

Myosotis ‘Rosylva’ forms low-growing mounds reaching 6-10 inches in height and 8-12 inches across. ‘Rosylva’ has great flower power as it produces masses of 1?3- to 2?3-inch flowers in the early spring. The fragrant, bubble-gum-pink flowers with yellow eyes nearly cover the entire foliage in the early spring. They are commonly used in containers, patio pots and in small mass or border plantings. Myosotis performs well across much of USDA Hardiness Zones 3 to 8 and AHS Heat Zones 7 to 1. As mentioned above, they are cool-season plants and perform best when grown under these conditions. They tend to struggle and may perish under extreme heat or during extended dry periods.

Propagation

Myosotis ‘Rosylva’ is easily propagated by seed and is most commonly sown in 288- or 220-cell plug trays. Since 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 65-72° F for germination. Many growers utilize germination chambers during this stage to provide uniform moisture levels and temperatures.

Seedlings will emerge 10 to 14 days after sowing. Following germination, lower the temperature to 64-68° F and reduce the moisture levels somewhat, allowing the growing medium to dry out slightly before watering to help promote rooting. Fertilizers are usually applied once the true leaves are present, applying 100-ppm nitrogen every third irrigation or 50 ppm every irrigation using a balanced water-soluble source. When the plugs are grown at 65° F, they are usually ready for transplanting in five to seven weeks.

Production

‘Rosylva’ is often produced in 1-gallon or smaller containers with a single plug planted in the center. After the plug has been transplant-ed, the growing medium should be even with the top of the plug.

Forget-me-nots perform best when grown in a moist, well-drained medium with a slightly acidic pH of 5.6-6.0. Production of myosotis in media with high pH levels is likely to lead to chlorotic foliage (interveinal) caused by iron deficiency. They are light feeders and prefer to be fed with nitrate-nitrogen fertilizers (as opposed to ammonium-based) with low phosphorus levels. Providing moderate to high fertility levels, using ammonium-based fertilizers, or high phosphorus causes them to appear lush and leafy. Growers commonly deliver nutrients using either a constant liquid fertilization program, feeding at rates of 50- to 75-ppm nitrates or 100-150 ppm as needed. Controlled-release fertilizers incorporated at a rate equivalent to 3?4-1 pound of elemental nitrogen per yard of growing medium is also an acceptable method of delivering nutrients. When irrigation is necessary, I recommend watering thoroughly then allowing the soil to dry slightly between waterings.

With their compact growth habit, it is usually not necessary to control the plant height. However, during the winter months, during periods of low light levels, when grown at high plant densities, or when grown with luxury nutrient levels, excessive plant growth might occur, requiring some type of height management strategy. Under certain circumstances, it may be necessary to use chemical plant growth regulators to control the growth of myosotis. If PGRs are necessary, I recommend applying B-Nine (daminozide) at 2,500 ppm or Sumagic (uniconazole) at 5 ppm; one or two applications seven days apart should provide adequate height control.

Insects and Diseases

Aphids are the most troublesome insect pests of myosotis. Implementing a preventive program to control aphids may be worth considering. I have found that a single preventive drench application with products containing acetamiprid, imidacloprid or thiamethoxam provides control of aphids throughout the entire production cycle. Caterpillars, leafhoppers and spider mites may also be observed feeding on myosotis.

Botrytis, powdery mildew and root rot are the diseases most often observed by growers. Of these pathogens, Botrytis is the most prevalent and usually occurs late in the crop cycle once the canopy closes in and they begin to bloom. In most cases, Botrytis can be prevented or reduced by providing adequate spacing, good air circulation at all times, maintaining a relative humidity below 70 percent, selling plants when the flower buds just begin to open and, if necessary, implementing a preventive fungicide spray program using products containing chlorothalonil or fenhexamid.

Most of these insects and pathogens can be detected through routine scouting programs, and if necessary, control strategies can be implemented following their detection.

Forcing

‘Rosylva’ is easy to force into bloom and is most commonly produced for early spring sales. Myosotis has an obligate cold requirement for flowering. I recommend vernalizing them in the final container or as large plugs (72-cell or larger) for a minimum of nine weeks at 35-44° F. After the cold requirement is achieved, they can be grown at any day length, as they are day-neutral plants. The length of the photoperiod does not have any effect on the time to flower or the number of blooms produced.

The time to bloom after vernalization is a function of temperature. ‘Rosylva’ grown at 63° F will take approximately six weeks to reach flowering, while plants grown at 58° F will flower in eight weeks.

Producing them at cooler temperatures increases the time to flower, but it will improve the overall quality of the plant, such as the color intensity of the foliage and flowers.

For full, flowering plants for spring sales, plant them during the late summer of the previous season. I recommend transplanting plugs into the desired container during late August to early September, bulking them up before winter, overwintering them and forcing them to bloom in the early spring. Many growers successfully produce flowering plants by transplanting large, vernalized plugs in the late winter and forcing them at 60-65° F for approximately seven weeks.

Availability

Myosotis sylvatica ‘Rosylva’ is available to the industry as seed, plug or finished container. The seed is supplied by Benary Seed (www.benary.com) and is available through many seed distributors. Plugs can be acquired from C. Raker & Sons, Inc. (www.raker.com), Jolly Farmer Products, Inc. (www. jollyfarmer.com), Swift Greenhouses, Inc. (www.swiftgreenhouses.com) or from several reputable plant brokers.

About The Author

Paul Pilon is a horticultural consultant, owner of Perennial Solutions Consulting (www.perennial-solutions.com) and author of Perennial Solutions: A Grower’s Guide to Perennial Production. He can be reached at (616) 366-8588 or paul@perennial-solutions.com.

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