In recent years, the popularity of solidago cultivars has increased. Breeding efforts and awareness have led to the wider use and acceptance of this underutilized perennial. Many solidago species are considered weeds rather than desirable ornamental plants; however, plant selection and breeding efforts have improved its aesthetic characteristics and plant habit in recent years.
Also known as goldenrod, solidago has wrongfully been accused of being a source of pollen or an allergen thought to have affected numerous allergy sufferers. The truth of the matter is the pollen of solidago is not an allergen, and it is too heavy to be carried by air currents and must move from plant to plant on the bodies of insects. The pollen from ragweed, which flowers at the same time as goldenrod, is the pollen source that causes many individuals to suffer from hay fever.
Solidago ‘Little Lemon’ is a great hybrid cultivar sure to catch the attention of landscapers and gardeners alike. ‘Little Lemon’ is the lightest yellow-flowering goldenrod available and produces a bright display of lemon-yellow flower spikes. The compact size — reaching only 8-10 inches in height when blooming — and free branching habit make ‘Little Lemon’ a great addition to late-season perennial programs. Flowering naturally occurs for several weeks during August and September.
‘Little Lemon’ prefers full sun and is widely grown throughout USDA Hardiness Zones 5-9 and AHS Heat Zones 9-5. This solidago is very versatile and can be used in a number of ways including container, border and mass plantings. It is suitable for production in a wide range of container sizes from 4 inch to 1 gal. With these characteristics, ‘Little Lemon’ can be marketed alongside fall bedding plants and makes a good component for combination pots.
‘Little Lemon’ is vegetatively propagated from tip cuttings and can only be propagated by licensed propagators. Since a plant patent is being sought, unlicensed propagation of this cultivar is prohibited.
Tip cuttings should be taken while they are vegetative and non-flowering. The cuttings should measure approximately 2 inches in length and contain several nodes. Place them under low misting regimes for about the first 7-10 days of propagation. Misting can gradually be reduced as the cuttings form calluses and root primordia. Cuttings are usually rooted in approximately 3-4 weeks with soil temperatures ranging from 68 to 74º F. It is beneficial to begin constant liquid feeding with 150-ppm nitrogen at each irrigation beginning 10 days from sticking.
Growers typically plant one rooted liner per 6-inch or smaller-sized container. When planting, the plugs should be planted so the original soil line of the plug is even with the surface of the growing medium of the new container. Solidago ‘Little Lemon’ performs best when grown in a moist, well-drained medium with a slightly acidic pH of 5.5-6.5.
Solidagos are moderate feeders and perform best when a constant liquid fertilization program is used, feeding at rates of 100- to 150-ppm nitrogen. Controlled-release fertilizers can be incorporated into the growing mix at medium to high rates; applying 1-11⁄4 lbs. of nitrogen per yard of growing medium is recommended. Goldenrod requires an average amount of irrigation. When irrigation is necessary, water plants thoroughly and allow the soil to dry slightly between waterings. ‘Little Lemon’ has a naturally compact growth habit and usually will not require height-control strategies.
Goldenrod can generally be relatively free of insects and plant pathogens. Occasionally, aphids, thrips and whiteflies may appear and cause only a minimal amount of crop injury; they rarely require control strategies. The primary disease growers should watch for is rust (Coleosporium asterum), which often covers the leaves and stems with rust-colored pustules during late summer. Once rust is present, it spreads quickly through air movement and splashing water. Rust can be controlled using preventative sprays of Heritage (azoxystrobin), Contrast (flutolanil), Eagle (myclobutanil) and Strike (triadimefon) every 3-4 weeks, rotating chemical classes at each application.
Other diseases observed include damping off, powdery mildew and root rots. The occurrence of these diseases can be reduced by using adequate crop spacing, avoiding overhead irrigation late in the day, providing adequate air circulation and controlling humidity. Growers should use routine scouting programs to detect the presence of insects and diseases early and determine if and when control strategies are necessary.
‘Little Lemon’ is primarily produced for sales during the late summer months. The precise forcing requirements of solidago have not been fully researched at this time and tend to vary slightly from species to species. Solidago does not require a cold treatment, or vernalization, for plants to bloom. They will easily bloom when propagated from cuttings in their first growing season. However, they are considered to be cold-beneficial plants; providing a cold treatment increases the number of blooms per plant and slightly decreases the time necessary to reach flowering.
Goldenrod is considered an obligate long-day plant and will not flower unless it has been grown under long photoperiods. With a naturally compact growing habit, it is beneficial to allow plants to bulk up slightly before supplying long-day conditions. From the start of long days, it will take approximately 8-10 weeks for ‘Little Lemon’ to reach flowering when grown at 68º F.
Solidago ‘Little Lemon’ was bred by Danzinger “Dan” Flower Farm; it is brought to the North American market by PlantHaven, Inc. Licensed propagators of solidago ‘Little Lemon’ include DeGoede Bulb Farm, Floraexpo S.A. and James Greenhouses, with Florexpo S.A. supplying unrooted cuttings to the industry. Rooted liners are available from numerous perennial propagators across the country.