March 2009

Dicentra ‘Burning Hearts’ By Paul Pilon

Fern-leaf bleeding hearts are classic shade garden and woodland plants that have livened up shady landscapes for numerous generations and pro-mise to illuminate these drab areas for years to come. Dicentra 'Burning Hearts' is a recent introduction that offers growers many desirable attributes, such as a compact growing habit, extended bloom time and ease of production.

'Burning Hearts' forms mounds of attractive fern-like foliage reaching only 10-12 inches in height and 12 inches wide at maturity. Numerous deep rose-red, heart-shaped blossoms are suspended on curved stems above the feathery blue-gray foliage. It blooms the entire growing season, from mid-spring through the first frost. Fern-leaf dicentra can be easily produced in average, medium-wet, well-drained soils in locations with partial shade to partial sun across USDA Hardiness Zones 3 to 9 and AHS Heat Zones 10 to 1.

With its height attributes and early, predictable flowering, 'Burning Hearts' is suitable for production as a spring-flowering perennial, containerized plant, component of a mixed container, and even as an indoor flowering house plant. In the landscape, they are widely grown in shade and woodland garden settings as border plants or in small groups and mass plantings. Dicentra 'Burning Hearts' is a wonderful, easy-to-grow cultivar for commercial growers to add to their perennial offerings.

Propagation

Dicentra 'Burning Hearts' is a patented variety (PPAF), and asexual propagation is prohibited at this time. Skagit Gardens (www.skagitgardens.com) currently of-fers this variety to the industry as 72-cell liners.

Production

When transplanting liners, plant dicentra 'Burning Hearts' even with the soil line of the plug it was previously produced in. It performs best in a media that has good water-holding characteristics and, more importantly, adequate aeration. A well-drained media is very important in preventing the crown from staying wet too long, which can lead to crown rot. To reduce the likelihood of crown rot and enhance initial rooting, apply a broad-spectrum fungicide drench after planting using the combination of Subdue Maxx and Medallion, Subdue Maxx and Cleary's 3336, or Banrot applied alone using each product's labeled rates for drench applications.

Maintain the media throughout the production cycle with a pH from 5.5 to 6.4. They are light to moderate feeders requiring nitrate levels of 75-125 ppm under a constant liquid fertilizer programs or 200 ppm as needed. Several growers incorporate low rates (0.75 to 1.0 pounds of elemental nitrogen) of controlled-release fertilizers into the growing mix before planting to effectively provide nutrients to containerized dicentra. Fern-leaf bleeding hearts require an average amount of irrigation. They should be kept slightly moist during production to prevent them from going dormant, especially during the summer months. Avoid overly wet conditions to prevent crown rots. With its compact habit, it is usually not necessary to control plant height during production. If height control is required, daminozide (B-Nine or Dazide) is effective at reducing elongation. One to two applications of 2,500 ppm should provide adequate height control.

Insects and Diseases

Some insect pests, including aphids, caterpillars, fungus gnat larva, slugs, spider mites, thrips and whiteflies, may occasionally be found feeding on dicentra. However, they can generally be grown without insect feeding or significant injury from these pests. There are several plant pathogens, including downy mildew, Fusarium wilt, powdery mildew, rust, Sclerotium and Verticillium wilt, that may occasionally be observed in infected fern-leaf bleeding hearts. Insects and diseases can be detected with routine crop monitoring; control strategies may not be necessary unless the scouting activities indicate action should be taken.

Forcing

Dicentra 'Burning Hearts' is most commonly produced for early-spring sales and is relatively easy to force into bloom. It has an obligate cold requirement for flowering. They can be vernalized as a large plug (72-cell or larger) or in the final container. For early spring sales, it is recommended that dicentra be planted in the late summer or early fall, bulking them up, and vernalizing in the final container. This will result in fuller, more colorful plants when they bloom. Provide a minimum of nine weeks at less than 40¡ F before forcing them into flower.

Planting vernalized dicentra liners in the spring will still result in marketable product, but small liners will likely reach peak flowering before the plants have filled out the container. When potting them up in the spring, try to use large plugs (such as 21-cell liners) to reduce the amount of time required for bulking. If the plants are too small when they begin to flower, the flowers can be removed to encourage vegetative growth; they will rebloom in a few weeks.

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. 'Burning Hearts' that have been bulked up in the fall take seven to eight weeks to bloom when they are grown at 60¡ F. As mentioned above, it may take longer (10 to 12 weeks) to produce a marketable plant when small plugs are transplanted in the spring.

Availability

Dicentra 'Burning Hearts' was bred by Japanese breeder Akira Shiozaki and is being marketed in the United States by Skagit Gardens (www.skagitgardens.com). Finished containers can be purchased from many reputable finished growers or garden centers throughout the country.