Common Name: forsythia
Type: Deciduous shrub
Family: Oleaceae
Zone: 5 to 9
Height: 2.00 to 2.50 feet
Spread: 3.00 to 5.00 feet
Bloom Time: March to April
Bloom Description: Yellow
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Suggested Use: Hedge
Flower: Showy, Fragrant, Good Cut
Tolerate: Deer, Clay Soil, Black Walnut
Culture
Easily grown in loose, medium moisture, well-drained soils in full sun to part shade. Best flower production is in full sun. Tolerates average to poor garden soils. Moderate drought tolerance once established. Shrubs are vegetatively winter hardy to USDA Zones 5-8, but may not always flower well in Zone 5 because of harsh winter temperatures or late winter freezes of unopened flowers. Flower buds are typically lost when winter temperatures fall below -5°F. Development of unkempt growth often occurs if shrubs are not regularly pruned immediately after spring flowering (pruning done after mid-July will remove flower buds for the following spring). A wide range of pruning options exists for 6-10’ tall hybrids, one option being (a) an annual post-flowering removal of old wood combined with cosmetic shaping of the shrub, and (b) a major cut back of stems to almost ground level every 3-4 years for rejuvenation. Shrubs have good tolerance for urban conditions. Some cultivars may sucker. Cultivars are primarily propagated by rooted stem cuttings.
Noteworthy Characteristics
Forsythia is a genus of about 7 species of mainly deciduous shrubs from Eastern Asia with one species form Southeast Europe. They are great harbingers of spring with their early yellow flowers produced before the plants leaf out. Several hybrid selections have been made.
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.
'Happy Centennial' is a compact, spreading, deciduous shrub which typically grows 2-2.5' tall and spreads to 5' wide. Features slightly fragrant, light yellow flowers which appear in profusion before the leaves in late winter to early spring. One of the earliest blooming shrubs. Ovate, leathery, dark green leaves are attractive throughout the growing season, but fall color is usually unexceptional.
Problems
No serious insect or disease problems. Some susceptibility to leaf spot and crown gall.
Although forsythia is vegetatively winter hardy to USDA Zone 5, the flower buds of many forsythia are often damaged by cold winter temperatures and late freezes in Zone 5. This cultivar reportedly has good flower bud hardiness to approximately minus 20 F.
Uses
Group in borders. Foundations. Mass on banks or slopes. Sunny areas of open woodland gardens. Cottage gardens.
Also may be grown as a small hedge.