June 2004

Hosta‘Sum and Substance’ By Paul Pilon

For the last several years, hostas have been the top-selling perennial throughout North America and are a significant part of today's landscapes. Hosta 'Sum and Substance' is an eye-catching variety whose immense chartreuse-green leaves have caught the attention of professional landscapers and gardeners alike. The incredible size, with clumps reaching 3 feet tall x 5 feet across, make Sum and Substance the most impressive and popular gold hosta ever introduced.

Sum and Substance provides a stunning display as a specimen or background plant in landscapes throughout USDA Hardiness Zones 3-9. The best gold color is drawn out where plants have some exposure to direct sunlight. In the mid-summer, lavender flowers complement the chartreuse foliage.

With its breath-taking appearance and ease of production, Sum and Substance has earned the honor of being selected by the American Hosta Growers Association as the 2004 Hosta of the Year. In past years, it has received numerous awards and recognition including the 1984 Midwest Gold Award, 1984 Eunice Fisher Award, 1987 Presidents Exhibitor Trophy and was rated Number 1 in the The American Hosta Society's 1997 Popularity Poll.

Propagation

Sum and Substance is vegetatively propagated most commonly by division. Division entails dividing or splitting the crown into smaller sections that contain at least one bud and several adjoining roots. Growers can divide hostas throughout the growing season from spring to fall. Growers attempting to propagate this cultivar or any hosta (except Hosta ventricosa) from seed will not produce plants that are true to type. Vegetative propagation retains the desirable characteristics of the mother plant such as leaf color, shape and size. At certain times of the year, propagation of hostas or planting a bare root propagule may lead to disappointing results. Several weeks after planting, it is not uncommon for growers to observe fully flushed hostas, apparently ready to ship or ç sell, only to discover that a root system does not accompany the nice foliage. This becomes problematic when the consumer attempts to plant their nice new hosta into the landscape and discovers they have purchased a pot of soil with a plant sitting on top.

In the Midwest, the later the division is planted, the fewer the roots (if any) it makes and the lower the winter survival rate. In many cases, hostas will over-winter without a root system and flush top growth in the spring yet still not generate any new roots. Each cultivar varies slightly, but generally it is best to schedule your hosta plantings to be completed by late August. Planting after this time will lead to plants going into the winter without an adequate root system, which will carry over to spring and reduce the quality and salability of your hosta crop.

The rooting phenomenon (or lack of) is also observed when growers plant hostas during the winter months from bare root divisions. Hostas tend to root poorly up until April or May, again they will flush top growth fine but not develop a root system. I would recommend growers plant their hostas from June-August of the current year for next spring's sales to avoid any possibility of providing un-rooted hostas into the marketplace.

Production

Sum and Substance is a large-leaved cultivar that is best suited for 1-gal. or larger containers. Like most hosta cultivars, Sum and Substance is relatively easy to grow, provided a few simple requirements are met. Bare root divisions should be planted in a well-drained potting medium. Most growers use a bark-based mix, which provides adequate drainage for long periods of time. The division should be planted so the "eyes" or the growing points are at or just below the soil surface. It is not uncommon for bare root divisions to develop a surface mold on them before they are planted. This mold is rarely a concern and should not be detrimental to crop production. Whether a mold is present or not, it is a good practice to apply a preventative fungicide drench after planting, using Cleary's 3336 (Cleary Chemical Corp.), OHP 6672 (Olympic Horticultural Products) or FungoFlo (The Scotts Co.).

Marginal leaf necrosis is often observed on newly transplanted hostas or with plants lacking an adequate root system, particularly if the roots are exposed to insufficient moisture levels. This leaf necrosis is also commonly observed on plants potted in the fall, which do not have an established root system going into the winter months and begin flushing leaves in the early spring. Hostas with an adequate root system usually only show marginal leaf necrosis when they are produced under drought-like conditions.

Hostas are light to moderate feeders requiring only modest amounts of fertilizer. Although liquid fertilization programs providing 100 ppm nitrates are adequate to produce hostas, due to the longevity of this crop, it is generally better to deliver nutrition to hostas using controlled-release fertilizers. For plants potted in the late summer for the following spring's sales, I recommend using a controlled-release fertilizer with at least an eight-month release pattern. If possible, incorporate the time-release fertilizer into the growing medium prior to planting at a rate equivalent to 1 lb. elemental nitrogen per yard. Otherwise, I would recommend growers apply a top dress of these materials to the top of the growing medium after plants have been potted. For top dressing, growers should use the medium rate ç recommendations provided on the fertilizer label. Although generally not a concern, the optimum pH of the growing medium is 5.8-6.5.

Once established, hostas can be allowed to dry out between each watering. When hostas are being produced for container sales, it is best to produce them in an area that receives at least partial shade. Many growers use a 30-percent shade cloth over the production area to reduce the exposure to direct sunlight. Many hosta cultivars like Sum and Substance can be produced under full sun conditions when they are grown in the landscape. However, when being produced in containers these cultivars tend to prefer some exposure to shady conditions. Container production provides more stressful conditions such as higher root zone temperatures and more dramatic swings in the moisture level surrounding the roots than when plants are grown in the ground. These stresses make even sun-loving hosta varieties more sensitive to exposure to high light levels and prone to sunscald on their leaves.

Hostas will naturally become dormant in the fall as the daylength shortens. A cold period of at least six weeks at 40¼ F is recommended to reinitiate growth. Following the cold treatment, Sum and Substance can be flushed at temperatures between 60 and 70¼ F. At 65¼ F, it will take approximately nine weeks to force a 1-gal. crop of Sum and Substance to shippable size.

After the cold period, hostas will flush leaves regardless of the daylength. Many growers forcing them under short-day conditions often observe an initial flush of leaves followed by a vegetatively dormant state. Hostas have an obligate long-day requirement for continued leaf formation. When producing hostas for early sales, assuming the natural daylength is less than 14 hours, it is recommended to provide long-day photoperiods by extending the daylength or providing night-interruption lighting for four hours between 10 p.m. and 2 a.m. to prevent the dormant phase.

Sum and Substance is relatively free of insect and disease problems. The most prevalent pests to hostas are slugs. Sum and Substance is more resistant to slug feeding than many hosta cultivars. For controlling slugs, I would recommend using slug baits such as Deadline (Pace International) or Sluggo (Monterey Lawn & Garden) around the production area on a monthly basis. Aphids, spider mites and thrips may also be observed feeding on hostas, but they rarely become problematic. During the overwintering period, mice and voles commonly feed on the crowns and roots below the soil surface. It is recommended to apply mouse baits such as Ramik (Hacco) throughout the production site during the winter months.

Availability

Sum and Substance is widely produced as a bare root division, plug liner and finished container. Contact your local perennial producer or plant broker for availability of this variety.