Plant of the Month: Asiatic Hybrid Lilies

Pink Asiatic Hybrid Lily

Pink Asiatic Hybrid Lily

In between early summer and high summer, among the best perennials to join June-blooming roses are the Asiatic hybrid lilies. Stately and strong, they provide a welcome linear accent in the garden. The multitude of colors and patterns makes it almost impossible not to find a suitable selection to enhance any color scheme or garden plan. Upward facing, outward facing or down facing, the petals are typically smooth-edged and may be recurved. For greatest visual impact, plant in groups of at least three.

Typical Asiatic hybrids are not fragrant, although the new Longiflorum-Asiatic Hybrids (LA Hybrids) are fragrant, because they are crosses with the Easter lily (Lilium longiflorum). Colors are limited due to the recent introduction. LAs bloom at the same time as Asiatic hybrids, but the foliage emerges earlier so they are not as suitable for areas that experience late frosts in the spring. The LAs are available from B&D Lilies in the United States and from Dutch growers in Europe.

Planting Asiatics

Reputable online bulb sources begin shipping in October, and the bulbs should be planted as soon as they arrive. Use similar timing of cool fall weather if purchasing bulbs locally. Plant at three times the depth of the bulb and 12″ (30 cm) apart. Lilies require moist but well-draining soil. Plant Asiatics in full sun to avoid leaning stems. Site them for plenty of air circulation to minimize problems with Botrytis Blight. The following season after planting, begin an annual fertilization program with a product specifically designed for bulbs, fertilizing one month before and one month after bloom.

Insect Pests

Lily leaf beetle larvae photo courtesy of Wisconsin Pest Bulletin

Lily leaf beetle larvae photo courtesy of Wisconsin Pest Bulletin

In Canada, on the East Coast, and increasingly in other parts of the U.S., the Red Lily Beetle can be a problem. Wisconsin reported its first infestation this month. The beetle overwinters in the soil and emerges in spring to eat leaves, stems and buds. Easily identified, the beetle is 1/4″-3/8″ (6-9 mm) long, with a solid red body and long antennae; however, it’s the larval stage at which pest management is most effective. The photo at right is provided for assistance in identifying the larvae.

Control the beetle using spray drenches of neem oil to the point of runoff so that the product drips onto the soil below the plant. This is most likely to be effective on early larvae rather than adults. Repeat every 5-7 days where larvae are evident. Adult beetles can be handpicked and may also be repelled by neem oil. Keep in mind that the beetle is active from April through September, so you’ll need to be vigilant all summer if the beetle is present.

Diseases

The main fungal problem for Asiatics is Fusarium oxysporum wilt, a root rot that infests overly moist soil. An excellent article from the University of Illinois on Fusarium oxysporum appears here. If fusarium does enter the soil, lilies will need to be moved to a new, fusarium-free location or else the soil will need to be replaced. In 1994, the Journal of the American Society of Horticultural Science published findings of two Dutch researchers on those Asiatic Hybrid Lilies most resistant to fusarium. The full article (PDF) and disease ratings can be read here; the lower the number, the more fusarium-resistant the lily. Among the top performers were Connecticut King (dark yellow), Prominence (orange) and Yellow Blaze (speckled yellow).

Always purchase bulbs from a reputable source, such as B&D Lilies or John Scheeper, among others, in the U.S. These companies can answer your questions on disease resistance, suitability for your planting plans and their own performance experience with bulbs in the field.

Transplanting and Dividing 

At some point you may find that your lilies need more space or would look more attractive as part of an alternate grouping. Or maybe your lilies aren’t putting out as many blooms anymore. Whether transplanting or dividing, wait until cool fall weather after the lily leaves have turned yellow to begin your project.

Begin by cutting back the stems to 5″-6″ (13-15 cm) above the soil line. Place your spading fork 4″-6″ (10-15 cm) away from the outermost stem and dig down to 12″ (30 cm) below the soil line. Maintaining the same distances, fork around the plant in a circle until you can lift the plant out. Gently brush away all excess soil from the bulb. If transplanting, simply move the bulb(s) to your newly forked location, replanting at the appropriate depth and covering with soil.

If dividing, follow the same procedure as for transplanting, but divide the bulb into smaller clumps either by hand or with a sharp, sterile knife. Replant your divided bulbs using the same guidelines as planting fresh bulbs. If desired, use a light mulch to top dress the bulbs if soil tends to dry out rapidly.

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