Common Name: greenstem forsythia
Type: Deciduous shrub
Family: Oleaceae
Zone: 6 to 8
Height: 0.75 to 1.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: March to April
Bloom Description: Yellow
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Flower: Showy
Tolerate: Deer, Clay Soil, Black Walnut
Culture
Easily grown in average, medium moisture, well-drained soils in full sun to part shade. Best flower production is in full sun. Good tolerance for urban conditions.
May be pruned to the ground after flowering in alternate years to revitalize.
Noteworthy Characteristics
Forsythia viridissima, sometimes commonly called green-stem forsythia, is an upright deciduous shrub that grows to 10’ tall on branches clad with elliptic-oblong to lanceolate leaves (to 6” long) that are toothed above the middle. Yellow green flowers (to 1” long) bloom in early spring. It is one of the parents of the popular F. x intermedia cultivars.
Genus name honors William Forsyth (1737-1804), Scottish superintendent of the Royal Gardens of Kensington Palace and author, among other works, of A Treatise on the Culture and Management of Fruit Trees which in its day was probably the most widely read work on the subject.
Specific epithet means very green.
‘Bronxensis’ is an unusual low, spreading, flat-topped cultivar that grows to only 12” tall but spreads to 24-36” wide. Ovate bright green leaves (to 1.75” long) are serrated. Light yellow flowers. ‘Bronxensis’ was initially grown from seed at the Bronx Botanical Garden in New York City in 1939.
Problems
No serious insect or disease problems. Although vegetatively winter hardy to USDA Zone 5, the flower buds may be damaged in some years by cold winter temperatures and/or late spring freezes.
Uses
Interesting ground cover. Slopes or banks. Rock gardens. Foundations. Sunny areas of open woodland gardens.