February 2010 Culture

Oriental Lily ‘After Eight’ By Paul Pilon

With their flamboyant and sweetly scented blooms, Oriental lilies definitely draw consumers' attention in garden centers. In the past, Orientals were primarily grown and marketed as potted plants that were sold around major holidays such as Easter or Mothers Day. However, Oriental lilies can be easily produced for other markets and fit the commercial perennial trade well.

'After Eight' is a genetically short Oriental lily introduction from Lily Looks. It bears numerous intense pink, fragrant flowers on short, sturdy stems. In containers, it commonly reaches 14-18 inches tall while in bloom and remains less than 24 inches tall in the landscape during subsequent years. 'After Eight' is one of four exciting cultivars currently offered as the Sunny series, marketed under the Lily Looks umbrella. This series includes 'Sunny Borneo', white with light-pink blush; 'Sunny Bonaire', a soft pink; and 'Sunny Sulawesi', a bright white. Each cultivar produces an abundance of fragrant blooms on strong short stems.

With its compact growing, 'After Eight' is well suited for production in greenhouses and nurseries, and can be produced and marketed throughout the year. It is commonly sold as a potted plant, used in patio pots or flower boxes for seasonal interest, or as a landscape perennial. These lilies can be produced in sunny locations throughout USDA Hardiness Zones 3 to 10. With their ease of production, numerous growers are adding Oriental lilies to their perennial programs; 'After Eight' and the other genetically short Sunny series cultivars fit nicely into grower's production systems and provide an impressive display of color at retail locations.

Propagation

It is not economical or practical for growers to propagate Oriental lilies, grow the bulbs to maturity and then produce a finished crop. All Lily Looks lilies are patented varieties, and any propagation without license is strictly prohibited. Commercial growers obtain fully mature, precooled, ready-to-plant bulbs of 'After Eight' and other Oriental lily cultivars to pot into their final containers.

Production

Precooled, frozen bulbs are packed in peat moss, which helps retain some moisture around the bulbs and prevents them from drying out during storage and shipping. It is important to defrost bulbs gradually by thawing them out at 50-55¡ F for several days before potting. Frozen bulbs can be stored for up to two weeks in a cooler at 34-36¡ F or for longer periods when they are kept frozen. Warmer storage temperatures cause the bulbs to sprout prior to planting and may result in breakage while they are being removed from the peat moss; once the tender shoot is broken from the bulb, the bulb is useless and should be discarded.

Once the bulbs have thawed out, they can be separated from the peat moss. Take care not to remove the scales of the bulb during sorting. Many growers submerge the bulbs in water for at least 10 minutes to bring them to a uniform moisture level prior to planting. Once the bulbs are rehydrated, they should be planted immediately. An alternate method would be to water them in thoroughly after potting; this allows good contact between the growing mix and the bulbs and improves the uniformity of the crop.

'After Eight' is most commonly produced in 1-quart to 1-gallon containers. The number of bulbs needed varies with container size, customer specifications and the price point of the product. Small container sizes, such as quart containers, usually contain one bulb each, whereas larger container sizes, such as gallon pots, often contain up to three bulbs.

Oriental lilies perform best when they are grown in a moist, well-drained, porous growing medium with a slightly acidic pH of 6.5-6.8. Most commercially available peat- or bark-based growing mixes work well, provided there is adequate drainage. The bulbs must be planted deeply with a minimum of three inches of growing mix above the bulb. There should also be a minimum of 1 inch of growing mix under the bulb. Place the bulb near the center of the pot with the bulb pointed upward, not sideways, to help the stems come up near the center of the pot. When planting multiple bulbs in each container, it is recommended to space them accordingly and point the bulbs at a 45-degree angle to the outside of the pot. This provides proper stem spacing and adds balance/fullness to the container. A proper planting depth is important to provide adequate stem root development (the majority of the roots grow on the stem between the bulb and the top of the media surface). Stem roots are the primary source of nutrition and moisture uptake as well as supporting and anchoring the plant.

During emergence, uniform moisture levels are important. The growing medium should be watered well after planting and kept uniformly moist thereafter. Watering must be carried out sparingly until they have emerged; the soil should never be allowed to dry out, while at the same time it must not be kept too wet. The amount of irrigation can be increased when the shoots are 3-6 inches tall, as the stem roots are usually well formed at this time. When providing irrigation, water thoroughly and let them dry out slightly between watering. Once the flower buds are visible, the growing media should never dry out; overly dry conditions at this stage could cause the flower buds to abort.

Oriental lilies are light to moderate feeders. Early in production, it is not necessary to apply fertilizers as there is a sufficient amount of nutrients in the bulb to support shoot growth. As the plants reach 2-3 inches tall, fertilizers can be applied. Water-soluble fertilizers can be applied weekly using 150- to 200-ppm nitrogen or with a constant liquid fertilization program using rates of 75- to 100-ppm nitrogen with every irrigation.

One of the attributes of the Sunny series cultivars are their short habits compared to many of the other genetics on the market. Thus, plant growth regulators are not necessary to reduce stem elongation in 'After Eight'.

Insects and Diseases

There are relatively few insects and diseases affecting the production of Oriental lilies. Aphids, fungus gnats and shoreflies are the insects observed most frequently when producing Orientals inside greenhouses; growers producing them outside may occasionally also observe grasshoppers and lily leaf beetles (Lilioceris lilii) feeding on them. Botrytis (B. elliptica, B. liliorum and B. cinerea) is the primary foliar disease that infects Oriental lilies and first appears as pale tan spots on leaves, stems or petals; these spots enlarge rapidly and often cause plant tissues to collapse and the plants to blight. Botrytis can be prevented by keeping the foliage and flowers as dry as possible using adequate plant spacing, providing adequate air movement, avoiding overhead irrigation while the plants are blooming, and watering early in the day. Root rots caused by the pathogens Pythium and Rhizoctonia are likely to occur when they are kept overly wet.

Temperature and Scheduling

The main factor influencing the proper timing of Oriental lilies is temperature. Maintaining proper night temperatures during production is crucial; after they have emerged, night temperatures below 59¡ F will greatly decrease crop performance and increase the time to flower.

During emergence, maintain soil temperatures of 55¡ F. After the majority of the lilies have emerged, usually within two weeks of potting, it's more important to monitor and control the air temperature. Following emergence, maintain 24-hour average air temperatures of 68¡ F. I recommend growers provide 65¡ F night and 70¡ F day temperatures. Cooler temperatures dramatically delay crop development, and warmer temperatures hasten development and most often reduces the quality characteristics of the crop. Keep in mind that colder night temperatures will adversely affect crop development.

At these temperatures, 'After Eight' will take 12 to 13 weeks from potting to bloom. From the visible bud stage (flower buds visible on the top of the plant), it takes approximately 40 days to bloom with a 24-hour average temperature of 68¡ F. The size of blooms and intensity of the flower color can be increased when they are grown slightly cooler during the last couple of weeks of production (60¡ F night/65¡ F day).

Availability

Oriental lily 'After Eight' and the Sunny series cultivars are available from Zabo Plant USA (www.zabo plant.com) and 2Plant International (www.2plant.com). They are available to the industry as 12/14-centimeter, 14/16-centimeter, 16/18-centimeter and 18/20-centimeter bulbs.