Forsythia

Green forsythia was among the first of the forsythias to have been brought to Europe. The Scottish botanist and plant hunter Robert Fortune discovered it in eastern China, first in the garden of a mandarin and later in the nearby mountains, where it grows wild along rivers and streams. In Europe it was crossed with weeping forsythia (F. suspensa) to produce the handsomely flowered border forsythia, F. x intermedia.

Green forsythia grows erect, a shrub to almost 3 metres, with bright green branches and narrow leaves, toothed in the basal third. It flowers yellow like the other forsythias in early spring before leaf flush.

There has been little experience of its cultivation in Finland. From the literature, it is frost tender in climates similar to Finland’s. A small group has been planted at Mustila in 2010, on Atsalearinne (Azalea Slope), with hopes of spring flowering. And flower it has, F. viridissima being the last of the genus to bloom, which has protected it from spring frosts.

Early in the Finnish spring, i.e. around April-May, small yellow star-shaped flowers open on Korean forsythia shrubs, on the previous season’s growth or at the base of the leaves. After flowering is over, the shrub can be recognised by its leaves and habit: the leaves are dark green, broadly oval and bluntly pointed; the habit is broad, with curving shoots and root suckers.

Korean forsythia is native to a small area in central Korea. It was first ”found” by the famous plant hunters Takenoshi Nakai and E. H. Wilson, by coincidence both in the same area, the Kümgangsan or Diamond Mountain in what is now North Korea, a spot famed for its natural beauty; and both discoveries happened the same year, 1917. The Korean species is one of the few forsythias hardy in Finland. It has been grown at Mustila since the 1930s. The shrubs winter well enough but flowering may be sparse.

The forsythias attract deserved attention when they flower brilliantly in spring. In addition to the old favourites, the Korean forsythia (F. ovata) and the variety F. ‘Northern Gold’, the extremely promising F. mandshurica deserves attention. It is native to a small area of north-east China and has held elite plant status in Sweden for years, while in America it is considered one of the hardiest of the genus. It has long been grown in Finland, too, but has been limited to a few collections.

The yellow flowers are larger than most of the other forsythias and appear earlier, at Mustila as early as the beginning of May. The leaves are also slightly rounder and larger than in other forsythias. In autumn they turn yellow-orange or even wine-red. The shrub is erect in habit but only grows to about one metre high, though it spreads widely from root suckers.