Forsythia 'Arnold Dwarf'
Common Name: forsythia
Type: Deciduous shrub
Family: Oleaceae
Zone: 5 to 8
Height: 2.00 to 3.00 feet
Spread: 4.00 to 7.00 feet
Bloom Time: March to April
Bloom Description: Yellow
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Suggested Use: Hedge
Flower: Showy
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 degrees 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.

'Arnold Dwarf' is a vigorous, compact, low-spreading, woody shrub which is often grown primarily as a ground cover and secondarily for its spring flowers. Plants typically grow to 2-3' tall but spread to 7' wide or more. Broad-petaled, axillary, golden yellow flowers appear in early spring before the foliage emerges. Bloom is often much less profuse than on taller forsythias. Plants sometimes will not flower at all until the 5th year. Ovate, light green leaves (to 2 1/2" long) with serrated margins are born on arching branches that will root where they touch the ground. Leaves turn a non-descript yellow in fall. Genus name honors William Forsyth (1737-1805), Superintendant of the Royal Gardens of Kensington Palace. 'Arnold Dwarf' is the result of a cross of F. x intermedia and F. japonica var. saxatilis performed at the Arnold Arboretum in 1941 by Harvard Professor Karl Sax. Cultivar name honors the Arnold Arboretum and the dwarf size of the shrub.

Problems

No serious insect or disease problems. Some susceptibility to leaf spot and crown gall.

Garden Uses

Group in borders. Foundations. Mass on banks or slopes. Sunny areas of open woodland gardens. Cottage gardens.

Dwarf hedge.