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TREES & plants

Green-stemmed Forsythia

Spring flowers of green-stemmed forsythia, cultivar 'Bronxensis'.

Green-stemmed forsythia, sometimes called Korean forsythia is an upright, flat-topped shrub reaching 6 to 10 feet high and wide. Bright, 1-inch yellow flowers have a slight green tinge and appear a few weeks after other forsythia.  Green-stemmed forsythia is one of the parents for the popular Forsythia x intermedia cultivars.

This plant has some cultivated varieties. Go to list of cultivars.

 

Botanical name: 
Forsythia viridissima
All Common Names: 
Green-stemmed forsythia, greenstem forsythia, Korean forsythia
Family (English): 
Olive
Family (Botanic): 
Oleaceae
Tree or Plant Type: 
  • Shrub
Native Locale: 
  • Non-native
Landscape Uses: 
  • Massing, 
  • Hedge, 
  • Mixed border, 
  • Screen
Size Range: 
  • Large shrub (more than 8 feet), 
  • Medium shrub (5-8 feet), 
  • Small shrub (3-5 feet)
Light Exposure: 
  • Full sun (6 hrs direct light daily)
Hardiness Zones: 
  • Zone 5 (Chicago), 
  • Zone 6, 
  • Zone 7, 
  • Zone 8
Soil Preference: 
  • Alkaline soil, 
  • Moist, well-drained soil
Season of Interest: 
  • Early spring, 
  • Mid spring
Shape or Form: 
  • Irregular, 
  • Multi-stemmed, 
  • Oval, 
  • Upright
Growth Rate: 
  • Fast
More Information: 

Tree & Plant Care

Full sun for best flowers.
Adaptable to many soil types.
Prune after flowering to keep plants tidy.
Rejuvenate prune every few years by cutting to the ground.
Tolerant of black walnut toxicity and aerial salt spray.

Disease, pests, and problems

Crown gall, leaf spots, cankers

Native geographic location and habitat

China,  Korea

Bark color and texture 

Tannish-yellow with prominent lenticels.

Leaf or needle arrangement, size, shape, and texture

Opposite, 2 to 3 inch long lanceolate leaves, dark green with purple tinge in fall.
Square stems with prominent lenticels.

Flower arrangement, shape, and size

Bright yellow, 1 inch flowers in clusters along the stems.

Fruit, cone, nut, and seed descriptions

Sparse, brown dehiscent capsule; not ornamentally important.

Cultivars and their differences 

Bronxensis green-stemmed forsythia (Forsythia viridissima 'Bronxensis'): A low-growing ground cover forsythia reaching 1 foot high and 2 to 3 feet wide. Bright yellow flowers and bright green foliage.

Kumson Korean green-stemmed forsythia (Forsythia viridissima var. 'Kumson'): Upright, 6 to 8 feet high and wide; pale yellow flowers in spring followed by interesting dark green leaves accented with silver veins; fall color is maroon.

Suwan Gold green-stemmed forsythia (Forsythia viridissima 'Suwan Gold'): A small rounded shrub reaching 3 to 5 feet tall with arching stems. Bright yellow foliage with clear yellow flowers.

Citrus Swizzle™ McKCitrine green-stemmed forsythia ( Forsythia viridissima 'McKCitrine'): A low-growing, mounded 2 foot high and wide shrub with creamy-white variegated green leaf , which emerges chartreuse in spring. The pointed leaves turn a burgundy in fall.  Flowers pale yellow and not showy.

Forsythia viridissima or Green-stemmed Forsythia