July 2012 Culture

Perennial Solutions: Veronica ‘Sweet Lullaby’ By Paul Pilon

Veronica are treasured for their striking appearance and long-lasting bloom in the landscape. Speedwell comes in many shapes and sizes; however, the proverb "good things come in small packages" sure describes the attributes of Veronica 'Sweet Lullaby'. This compact prodigy of 'Giles van Hees' was bred by Kevin Hurd at Walters Gardens in Zeeland, Mich., and is marketed by Proven Winners.

'Sweet Lullaby' is a compact selection of spike speedwell with many notable characteristics for commercial growers, landscapers and homeowners. Compact spikes of pure baby pink flowers are produced atop small, bushy mounds of charming foliage in mid to late summer. When blooming, the attractive clumps remain compact, reaching only 6 inches tall.
Spike speedwell performs well throughout USDA Hardiness Zones 4 to 8 and AHS Heat Zones 9 to 1. They generally prefer locations with full sun; however, locations with filtered shade are acceptable. With its compact size, 'Sweet Lullaby' is ideal for use in combination planters, patio pots, and in border or mass plantings. Additionally, they attract butterflies and are resistant to deer feeding. With its compact size and flower power, 'Sweet Lullaby' would make a great addition to any perennial program.

Propagation
Veronica 'Sweet Lullaby' is vegetatively propagated by tip cuttings by licensed propagators; unlicensed propagation of this cultivar is prohibited. Licensed propagators root tip cuttings by sticking them directly into a pre-moistened, well-drained growing mix in liner trays with medium sized cells.

Place the cuttings under low-misting regimes for about the first seven to 10 days of propagation. When possible, it is best to propagate them under high humidity levels (90 percent relative humidity) with minimum misting. After the cuttings have begun to callus and develop roots, gradually reduce the amount of mist being provided each day. At this time, begin feeding with 100- to 125-ppm nitrogen once or twice per week using complete water soluble fertilizers. With soil temperatures being maintained at 68 to 74¡ F, they will usually be well rooted in three to four weeks.

Production

Veronica 'Sweet Lullaby' is best suited for production in 1-quart to 1-gallon containers. Speedwell perform best when they are grown in a moist, well-drained growing mix. After potting, the original soil line of the liner should be even with the surface of the growing medium of the new container.

Maintain the media throughout the production cycle with a pH between 5.5 and 6.2. They are light to moderate feeders and grow well under constant liquid fertilizer programs with rates of 75- to 100-ppm nitrogen with each watering or 150- to 200-ppm at every other watering. Nutrients can also be delivered using controlled-release fertilizers by topdressing using the medium recommended rate on the fertilizer label or incorporating into the growing medium prior to planting using a rate equivalent to 0.9 to 1.1 pounds of
elemental nitrogen per yard of growing mix. Plants will appear chlorotic and my exhibit delayed flowering when the fertility levels are too low.

Spike speedwell require average amounts of irrigation; they should be kept at moderate to moist moisture levels during production. Water thoroughly when irrigation is necessary and allow them to dry slightly between waterings.

With its compact habit, it is usually not necessary to control plant height when producing 'Sweet Lullaby'. The height can usually be controlled by providing adequate space between each plant. Under certain circumstances, particularly when produced at high plant densities, it may be necessary to tone them with plant growth regulators. One or two spray applications of either 2,500-ppm daminozide (B-Nine or Dazide) or 5-ppm uniconazole (Concise or Sumagic) can be used to control plant height if toning is necessary.

Insects and Diseases

A few insects and diseases may be observed on veronica during production. The most common insect pests are aphids, thrips and whiteflies; of these, aphids occur the most frequently. Botrytis, downy mildew and powdery mildew are the most common disease observed on spiked speedwell; of these pathogens, powdery mildew is the most prevalent.
Growers should utilize routine scouting programs to detect the presence of insects and diseases early and to determine if and when control strategies are necessary. However, many growers do implement preventative programs for controlling aphids since they are commonly found feeding on veronica.

Forcing

Veronica 'Sweet Lullaby' is easy to grow; blooming plants can be produced throughout the growing season by following a few guidelines. One of the most important factors for growing veronica is to understand that they have an obligate cold requirement for flowering. Plants will NOT flower unless they have been vernalized either as liners or in the final containers.

One method for growing veronica is to grow them as a traditional perennial where they are planted in the late summer or early fall the year before they are to be marketed. After planting, they are bulked up for at least six weeks prior to being exposed to cold temperatures. During the overwintering period, provide adequate protection from cold; similar to methods used for most perennials in your geographic location. The second method entails planting large liners that have been vernalized (minimum of six to nine weeks at temperatures less than 41¡ F) in the spring. Avoid spring or summer planting liners that have not been vernalized when sales are needed during the same growing season.

After the cold requirement is achieved, they can be grown at any day length as veronica 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. With both methods, the time to bloom after vernalization is a function temperature. 'Sweet Lullaby' takes approximately eight to 10 weeks to flower when it is grown at 65 to 70¡ F. Growing veronica with cooler temperatures improves the size of the flowers; however, cooler production temperatures increases the time to flower.

Availability
Veronica 'Sweet Lullaby' is being marketed by Proven Winners (www.provenwinners.com). Liners and bareroot are available from Walters Gardens, Inc. (www.waltersgardens.com). Liners may also be available through several Proven Winner propagators (www.pwcertified.com/grower/purchase/propagators.cfm).

Perennial Solutions: Veronica ‘Sweet Lullaby