October 2016 Production

Perennial Solutions: Salvia ‘Blue Marvel’ By Paul Pilon

There are several Salvia nemorosa cultivars on the market, but none of them have larger flowers than ‘Blue Marvel’ from Darwin Perennials. It not only rivals the competition with its ultra-large flower spikes, but ‘Blue Marvel’ also blooms continuously from spring through fall.

‘Blue Marvel’ has fragrant, narrow grayish-green leaves and forms fine textured, upright clumps that are highly attractive in the landscape. The beautiful spikes of long-lasting violet- blue flowers with blue overtones appear in the mid spring and gradually fade to reveal the burgundy calyces adding to its garden contributions. Removing the spent bloom will help keep them blooming. When flowering, the eye-catching clumps reach only 12 inches in height and can spread to 18 inches across.

Besides its flower power, ‘Blue Marvel’ has numerous desirable landscape attributes. The flowers are great for attracting hummingbirds, butterflies and other pollinators into the landscape. However, its fragrant foliage works well for keeping the critters such as deer and rabbits out. The flowers also make great cut flowers. Additionally, once established, salvia are also somewhat drought tolerant.

Salvia ‘Blue Marvel’ is hardy throughout Zones 4 to 9. It generally prefers locations with full sun; however, it performs best with partial shade in Southern locations. This great salvia cultivar can be used for container, border and mass plantings.

Its great characteristics are being noticed around the world; Salvia ‘Blue Marvel’ recently won “Best In Show” for the New Plant Awards, sponsored by the Royal Horticultural Society at this year’s HTA National Plant Show in Coventry, U.K. Consider adding this great award-winning plant to your perennial line up.

Propagation

Salvia nemorosa ‘Blue Marvel’ is vegetatively propagated by tip cuttings. It’s a patented plant; therefore, unlicensed propagation of this cultivar is prohibited. Licensed propagators can easily root them using the following guidelines.
The cuttings should be stuck the same day they are received. If this is not possible, store them at 45° F for no more than one day. For the fastest and most uniform rooting, dip the basal ends of the cuttings into a 1,000-ppm IBA solution prior to sticking. Stick the cuttings into liner trays containing a pre-moistened, well-drained growing medium or stabilized substrate. Maintain moderate mist frequencies during the first few days of propagation. After the cuttings are acclimated to the propagation environment, provide enough mist to keep the cuttings turgid throughout the day.

Avoid over misting as this will saturate the propagation mix and result in slow rooting and other cultural problems. When possible, it’s usually best to propagate salvia under high humidity levels (90 percent relative humidity) with minimal misting. Gradually decrease the mist throughout propagation.

Apply 75- to 100-ppm nitrogen beginning seven to 10 days after sticking the cuttings. Applying fertilizers at each irrigation or at least once per week will speed up rooting and keep the plants healthy. Misting is typically only required during the first 12 to 15 days and should be removed altogether as soon as the cuttings no longer flag or wilt during the middle of the day. Maintain soil temperatures of 68 to 75o F throughout the propagation cycle. Providing bottom heat will promote faster root development. Many propagators pinch newly rooted liners at approximately three weeks after sticking to improve branching and performance of the liners after transplanting. Liners take approximately five to six weeks from sticking to become fully rooted and ready for shipping or potting.

Production

Salvia ‘Blue Marvel’ is suitable for production in 1-quart up to 2-gallon containers. They perform best when grown in a moist, well-drained growing mix; many commercially available bark or peat mixes will suffice. Avoid planting the liners too deeply; the liners should be planted so the original soil line of the liner is even with the surface of the growing medium of the new container. Planting them too deeply will cause them to establish more slowly and possibly lead to the development of crown rots. Unless the liners were previously pinched, it’s often beneficial to provide a soft pinch one to two weeks after planting to promote more branching and fullness.

They are considered light to moderate feeders. Nutrients can be delivered using water-soluble or controlled-release fertilizers. Growers using water-soluble fertilizers can apply 100- to 125- ppm nitrogen with every irrigation or use 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. Maintain the growing mix throughout the production cycle with a pH between 5.8 and 6.2.

Salvia require average amounts of irrigation. Avoid excessively moist or wet growing conditions; this often leads to crown and root rots. Also, never let them wilt. When irrigation is necessary, water them thoroughly then allow the soil to dry slightly between waterings.

‘Blue Marvel’ is naturally compact and should not require height management strategies. If it becomes necessary to tone the plants during production, one or two spray applications of 2,500-ppm daminozide (B-Nine or Dazide) or using the combination of 2,000-ppm daminozide plus 3-ppm uniconazole (Concise or Sumagic) or 2,000-ppm daminozide plus 1,000-ppm chlormequat (Cycocel or Citadel) will usually be sufficient.

Insects and Diseases

Salvia can generally be produced relatively free of insects and diseases. Occasionally, aphids, spider mites, thrips and whiteflies may appear causing only a minimal amount of crop injury. Other insects that may be observed feeding on them from time to time include caterpillars, grasshoppers, leafhoppers, scale and slugs. Crown rots may develop when they are planted too deeply or when the growing mix is consistently wet. Other diseases to look for include Alternaria, Botrytis, downy mildew, powdery mildew, Pseudomonas and rust. Insects and pathogens can be detected with routine crop monitoring; control strategies may not be necessary unless the scouting activities indicate actions should be taken.

Temperature and Scheduling

Salvia ‘Blue Marvel’ can easily be scheduled and grown to produce flowering plants throughout most of the growing season. They can be grown as a traditional perennial and be planted in the late summer or early fall the year before they are to be sold. This approach is advantageous when the plants are needed for early sales. Allow at least six weeks in the fall for bulking prior to overwintering them.

‘Blue Marvel’ does not require cold for flowering; therefore, they can also be planted during the same growing season. When spring planting, growers can use fresh or vernalized liners. Salvia are long day beneficial plants and are usually grown under natural day lengths; however, they will flower faster when long days are provided. The best quality plants with the most flowers are obtained when they are grown under high light intensities (3,000 to 5,000 foot-candles).

It takes approximately 10 to 12 weeks to flower when they are grown with 24-hour average temperatures between 60 and 65° F. ‘Blue Marvel’ can be cut back for another full flush of flowers four to five weeks later.

Availability

Unrooted cuttings for propagation can be purchased from Darwin Perennials. Rooted liners can be purchased from a number of reputable perennial propagators including Green Leaf Plants, Gulley Greenhouse and Swift Greenhouses. Check with your plant broker/distributor for availability of URCs or rooted liners.