''Forsythia ''×'' intermedia'', or border forsythia,
is an ornamental deciduous
shrub of garden origin.
Description

The shrub has an upright habit with arching branches and grows to 3 to 4 metres high.
The opposite leaves turn yellowish or occasionally purplish in the autumn before falling.
The bright yellow flowers are produced on one- to two-year-old growth and may be solitary or in racemes from 2 to 6.
[
]
Origin
The hybrid is thought to be a cross between ''Forsythia viridissima
''Forsythia viridissima'', variously called the Chinese golden bell tree, green-stemmed forsythia, greenstem forsythia, and Korean forsythia, is a species of flowering plant in the genus ''Forsythia'', native to southern China and South Korea, a ...
'' and ''F. suspensa'' var. ''fortunei''.[ A plant of seedling origin was discovered growing in the Göttingen Botanical Garden in Germany by the director of the Royal Prussian Academy of Forestry in Münden, H. Zabel in 1878.] Zabel formally described and named the hybrid in ''Gartenflora
''Gartenflora'' was a German illustrated botanical magazine published in the period 1852–1940.
History
Founded in 1852 and edited by Eduard von Regel, the botanist and future director of the Saint Petersburg Botanical Garden, the magazine ap ...
'' in 1885. It was introduced to the Arnold Arboretum
The Arnold Arboretum of Harvard University is a botanical research institution and free public park, located in the Jamaica Plain and Roslindale neighborhoods of Boston, Massachusetts. Established in 1872, it is the oldest public arboretum in ...
in the United States in 1889.[
]
Cultivation
The hybrid is best suited to a position in full sun or partial shade and is drought-tolerant.[ Like some other forsythias it is one of the earliest shrubs to flower. Well adapted to temperature changes, it blooms with bright yellow flowers that are noticeable even in ]twilight
Twilight is light produced by sunlight scattering in the upper atmosphere, when the Sun is below the horizon, which illuminates the lower atmosphere and the Earth's surface. The word twilight can also refer to the periods of time when this ...
. It is one of several forsythia species that are widely cultivated in gardens and parks.
Cultivars
Cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...
s include (those marked have gained the Royal Horticultural Society
The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity.
The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (No ...
's Award of Garden Merit
The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions.
History
The Award of Garden Merit ...
):
*'Arnold Dwarf' – low-growing with pale yellow flowers[
*'Beatrix Farrand' – a particularly ]