June 2003

Veronica spicata ‘Royal Candles’ By Paul Pilon

Veronica ‘Royal Candles’ is a clump-forming, bushy cultivar often utilized in rock gardens, as a border plant or in containers. This cultivar has many distinguishing characteristics such as a compact growth habit, reaching only 10-12 inches tall; clean leafy foliage topped with numerous vertical flower spikes; and deep blue-purple flowers, lasting from late spring to midsummer. With these characteristics, it is well suited to production in small container sizes and for marketing alongside bedding plants.

Royal Candles was discovered in Kent, England, by an avid gardener, Heather Philpott. This cultivar, like other veronica varieties, prefers full sun, although in the South it performs best when grown under partial shade. The genus is named in honor of St. Veronica, as the markings on the flowers of certain species resemble the markings on the sacred handkerchief of St. Veronica. It is both heat and cold hardy in Zones 3-8. For more continuous blooming, it is recommended to deadhead or remove the old blooms.

Propagation

Royal Candles is vegetatively propagated, most commonly by tip cuttings and division by licensed propagators. Since a plant patent is being sought (PPAF), unlicensed propagation of this cultivar is prohibited.

Production

Royal Candles performs best when grown in a moist, well-drained medium that has a slightly acidic pH of 5.5-6.2. It is a moderate feeder and needs either a constant liquid fertilization program at rates of 50-100 parts per million (ppm) nitrate or a controlled release fertilizer incorporated at a rate equivalent to 1 lb. of nitrogen per yard of growing medium. Plants grown under a low fertility regimen will most likely appear chlorotic and exhibit a delay in flowering. ç

Royal Candles requires frequent irrigation. When irrigation is necessary, I recommend watering thoroughly then allowing the soil to dry slightly between waterings.

Generally, Royal Candles is relatively insect and disease free. Aphids, whiteflies and thrips will occasionally become problematic. Of these insect pests, aphids are the most prevalent. To control aphids, I recommend a preventative application of Marathon 60WP as a drench, which will generally ensure aphid-free plants from spring planting until the plants are shipped. Other preventative strategies include monthly spray applications of systemic chemicals such as Endeavor or Marathon II. Another reason I recommend using a preventative program such as the one described above, is that one application will prevent the occurrence of whiteflies as well.

Botrytis is occasionally a problem on the lower foliage where air movement is limited and the foliage often stays wet for extended periods of time after irrigation. Powdery mildew and downy mildew are also likely to be observed. At first, powdery mildew appears as small white, talcum-like colonies on the upper leaf surfaces, but under the right conditions, the disease may engulf the plant with a “powdery” appearance. Downy mildew usually appears first on the undersides of the leaves as a mass of white or gray spores, and often the upper leaf surface (directly above where the spores are observed) will appear mottled, discolored or blistered. To control these diseases, it is best to manage the environment by providing proper plant spacing, adequate air movement, low humidity, or if desired, follow a preventative spray program using the appropriate chemicals.

Controlling plant height is not usually necessary when producing Royal Candles under greenhouse conditions. Providing adequate spacing between plants will reduce stretch caused by competition. Under certain growing conditions or under high plant densities, it may be necessary, although not common, to use chemical plant growth regulators. In the northern parts of the country, I would recommend applying Sumagic at 5 parts per million. Applying 1-2 applications seven days apart should provide adequate height control.

Forcing

Forcing Royal Candles into bloom out of season is relatively easy, but there may be a few complications that could alter your ability to schedule blooming plants predictably. Although I have not seen any research on this particular cultivar of veronica, I feel it is safe to make a few assumptions based on research conducted on other cultivars of veronica. ç

Veronicas have an obligate cold requirement in order for them to flower. However, cuttings harvested from stock plants that have received a cold period will flower without receiving a cold treatment. For example, assume that you receive rooted cuttings from two suppliers in May. One supplier had stock plants that never received vernalization (cold requirement), and the other harvested cuttings from plants that were over-wintered. If you are looking to produce flowering plants for sale two months after you receive your rooted cuttings, you will be able to produce flowering veronicas only from the supplier whose stock plants were over-wintered and received the proper vernalization. The other supplier’s plants will grow to a shippable size but will remain vegetative.

I recommend cooling plugs or small containers of Royal Candles for a minimum of six weeks at 41¡ F. They will flower under any photoperiod after the cold requirement has been achieved during stock plant production, plug production or while grown in the finished container.

The time from vernalization to bloom is a function of temperature. Royal Candles grown at 68¡ F will take eight weeks to reach flowering, while plants grown at 60¡ F will flower in 11 weeks. Veronicas grown under warmer temperatures will have smaller flowers than plants grown under cooler temperature regimes. The best flower size is achieved by growing at temperatures averaging 60¡ F.

Availability

Royal Candles is brought to the marketplace by Plant Haven, Inc., Santa Barbara, Calif. Plugs are available only from licensed propagators. Finished containers may be purchased from many reputable companies across the country. For a list of licensed propagators, contact Plant Haven.