Perennial Solutions: Veronica Bomb Series
Over the years, veronica has become a staple perennial used in the American landscape. Past cultivars were known for their long blooming times and unfortunately many cultivars have a reputation for their floppiness. There has been much work with breeding efforts and plant selection to bring veronica cultivars with improved characteristics to the market.
The Bomb series provides a compact growing habit with plants reaching approximately 12 to 15 inches tall with uniquely branched flower plumes which are more similar to an astilbe flower than the traditional veronica flower spike. The tightly bunched, bright flower spikes comprised of hundreds of individual flowers bloom in mid-summer with the flowers gradually opening from the base of the spikes to the top which results in an exceptionally long bloom time.
The Bomb series was bred by Janus Verschoor and is currently comprised of three cultivars. ‘Blue Bomb’ produces hundreds of bright blue flowers on tightly bunched spikes atop attractive dark green foliage. ‘Pink Bomb’ appears very similar, but it produces pink flowers on the unique flower plumes. ‘Baby Bomb’ is a new addition to this series and will be available in 2014; ‘Baby Bomb’ is similar to ‘Blue Bomb’ but the plant is shorter and more compact.
Veronica grows well in sunny locations throughout USDA Hardiness Zones 4 to 8. Sites with filtered shade are also acceptable. The Bomb series is ideal for production in 1-gallon or smaller sized containers or can be used in combination containers or patio pots. In the landscape, they can be utilized as accent plants or used in border or mass plantings. Speedwell attracts butterflies into the landscape and are resistant to deer feeding. Additionally, the unique flower plumes can be used as cut flowers.
With its attractive appearance, unique blooms and flower power, the Bomb series is suitable for marketing alongside other novelty and premium perennials.
Veronica Bomb series is vegetatively propagated by tip cuttings by licensed propagators; unlicensed propagation of these cultivars
Moisten the rooting medium in the liner trays before sticking the unrooted cuttings (URCs). Although rooting compounds are not necessary for rooting Veronica, applying 750- to 1,000-ppm IBA to the basal ends of the cuttings prior to sticking or making foliar applications of 50- to 100-ppm IBA after sticking can improve the uniformity of rooting and slightly decrease the rooting time.
Cuttings should be placed under a low misting regime for the first seven to 10 days of propagation. Keep the humidity high (90 percent relative humidity) during this early stage. The misting can gradually be reduced after the cuttings have begun to callus and develop roots. Begin feeding with 100-ppm nitrogen from a complete water-soluble fertilizer at each irrigation once roots are present.
The cuttings usually take approximately two to three weeks to root with soil temperatures ranging from 68 to 74° F. Liners take approximately four to six weeks from sticking to become fully rooted and ready for transplanting.
Veronica Bomb series are best grown in 1-quart to 1-gallon sized containers; ‘Blue Bomb’ and ‘Pink Bomb’ are well suited for production in 1-gallon to 8-inch sized containers and ‘Baby Bomb’ is best produced in slightly smaller (1-quart to 1-gallon) sized pots. Although vegetative liners are available as starting materials, the best results are obtained when growers use bare root starting materials. Containers grown from bare root usually result in a fuller appearance with higher quality attributes. When using liners, it is beneficial to plant and bulk them in the late summer of the year prior to the intended market date. Planting liners of the Bomb series in this manner allows them to bulk up, increases plant vigor, produces more flowers per plant and results in more uniform flowering.
They can be grown in most commercially available peat- or bark-based growing mixes, provided there is adequate drainage. After potting, the original soil line of the liners should be even with the surface of the growing medium of the new container; bare root starting materials should be planted so the crown is just below the soil surface. Several growers have found it beneficial to pinch the plants several weeks after they emerge from dormancy. Pinching them results in fuller, better branched plants.
The Bomb series are light to moderate feeders and perform best when the pH is kept at 5.5 to 6.2. Growers using water soluble fertilizers commonly apply 75- to 100-ppm nitrogen with every irrigation or use 150 to 200 ppm as needed. Controlled-release fertilizers are commonly incorporated into the growing medium prior to planting at a rate equivalent to 0.9 to 1.1 pounds of elemental nitrogen per yard of growing medium.
Veronica require average amounts of irrigation; they should be kept at moderate to moist moisture levels during production. When irrigation is required, water them thoroughly and allow the substrate to dry slightly between waterings.
With their compact growth habit, it is usually not necessary to implement height control strategies when producing the Bomb series cultivars. The height can usually be controlled by providing adequate space between each plant. If it becomes necessary to tone the plants during production, one or two spray applications of either 2,500-ppm daminozide (B-Nine or Dazide) or 5-ppm uniconazole (Concise or Sumagic) can be applied.
Insects and Diseases
Veronica are susceptible to several insect pests and diseases during production and in the landscape. Aphids and whiteflies are the most prevalent pests growers observe. Other pests growers may see on occasion include caterpillars, leaf miners, slugs and western flower thrips. The primary pathogens which infect speedwell are Botrytis and powdery mildew. Additional diseases which may be observed include downy mildew and rust. Insects and diseases can be detected with routine crop monitoring to determine if and when control strategies are necessary.
The Bomb series of veronica are easy to grow; blooming plants can be produced throughout the growing season by following a few guidelines. Typically, growers market flowering plants in the mid spring and early summer. As mentioned previously, to produce the fullest containers, it is best to bulk the Bomb series in the fall from liners or to transplant bare root starting materials in the spring. When fall planting, allow a minimum of six weeks for quart-sized containers and up to 10 weeks for bulking 1-gallon sized containers prior to overwintering.
Veronica has an obligate cold requirement for flowering. Plants will not flower unless they have been vernalized either as liners, in the final containers, Provide at least six weeks of cold temperatures (35 to 44° F) to satisfy the cold requirement. Bare root starting materials planted in the spring are vernalized prior to shipping and planting.
Speedwell are day neutral plants and can be grown under natural day lengths after vernalization. The day length does not have any effect on the time to flower or the number of blooms produced. The time to flower after vernalization is a function of temperature. When they are grown at 65 to 70° F, the Bomb series takes approximately 8 to 10 weeks to flower. Growing them with cooler temperatures will increase the production time slightly.
Veronica ‘Baby Bomb’, ‘Blue Bomb’ and ‘Pink Bomb’ are being marketed by Growing Colors. Liners and bareroot are available from Garden World Inc. (www.growingcolors.com). 2Plant International (www.2plant.com) and Paridon Horticultural Ltd. (www.paridon.com) in Canada. Liners may also be purchased from Swift Greenhouses (www.swiftgreenhouses.com).