Of the forsythia (Forsythia), also called gold bells, there are seven different species worldwide, which have their main distribution in East Asia. With Forsythia europaea only one species is native in Southern Europe. Forsythia belong to the olive tree family (Oleaceae), so they are related to the olive tree, among others. The genus Forsythia was named after the English master gardener William Forsyth. He lived from 1737 to 1804 and, as Director of Horticulture for the English Crown, he managed several Royal Gardens throughout his life, including the gardens of St James and Kensington Palace. He was also a founding member of the Horticultural Society of London, from which the Royal Horticultural Society (RHS) emerged. Forsyth did not live to see the introduction of forsythia as a garden plant in Europe in 1833. Forsythia (Forsythia x intermedia) cultivated in the garden are all hybrid varieties of the two East Asian species Forsythia suspensa and Forsythia viridissima.
Forsythia are usually two to three metre high shrubs with initially upright growth that is strongly overhanging in old age. Their growth behaviour is basic and mesotonic, i.e. even from the older wood the dormant eyes at the base and in the middle of the shoots drift through into old age and usually form long and thin, tightly upright shoots. The bark is olive green on young shoots, ochre yellow to greyish yellow on older shoots and covered with strikingly large cork warts, so-called lenticels.
The leaves of the forsythia are opposite, eight to twelve centimeters long and ovoid with an elongated tip. The leaf margins are serrated and the blade is usually light to fresh green in colour. In sunny locations with rather dry and nutrient-poor soils, the deciduous leaves sometimes show a yellowish to violet autumn colour before the leaves fall.
Depending on the weather, the flowers usually appear in abundance from mid-March onwards. The yellow bells usually have four petals and a diameter of about three centimeters. They appear almost along the entire shoot length on the previous year’s and older wood as well as on its short side branches. The two to three-year-old shoots are the most flowering. From an ecological point of view forsythia are not the first choice for garden planting because most insects cannot do much with the flowers. For example, they supply neither nectar nor usable pollen to the bees.
Most hybrid varieties of forsythia are sterile or produce very little fruit. The ‘Beatrix Farrand’ variety, on the other hand, is reliably fertile: it forms brown, hard capsule fruits from its flowers.
Forsythia bloom most splendidly in full sunny locations. In the semi-shade and shade, the flowering splendour clearly diminishes and the crowns of the shrubs are far less dense.
Forsythia make only low demands on soil quality. They grow on all acidic to alkaline, permeable and not too dry soils. At very high lime contents the leaves sometimes turn yellow. A high humus content has a positive effect on the vitality of the flowering shrubs.
Usually forsythia are offered in the pot, more rarely than bare-root shrubs. Since they are easy to reproduce and grow quite quickly, they are considered to be simple flowering shrubs and are relatively inexpensive. When planting, you should make sure that the soil has a good water retention capacity. If the soil is poor, work in the appropriate amount of mature compost and deciduous humus and cover the soil surface with bark humus after planting the shrubs.
Forsythia do not need regular nutrient supply, but should be watered in time during summer drought. They quickly hang their leaves on dry soils in the heat and the lack of water also has a negative effect on the formation of flowers for the following year. Avoid soil cultivation in the root area and pluck individual wild herbs that grow through the mulch layer by hand. Since forsythia have hardly any problems with strong root competition, they can also be well underplanted with ground coverers to suppress weeds.
Forsythia belong to the flowering shrubs that grow old relatively quickly and become flower lazy. In order to maintain the joy of flowering, it is best to cut your forsythia annually until at the latest every three years after flowering from mid to end of April with a pruning shear and thinning it out. Remove all branches older than three years or cut them off above a younger, vital side shoot. If a forsythia has not been cut for years and its crown has literally fallen apart, you can put it completely on the stick in spring and then rebuild the crown from the strong young shoots.
In spring forsythia show an enormous abundance of yellow flowers. They are therefore visually very dominant and should be used sparingly and accentuated in the garden. For example, a single forsythia planted with blue bulb flowers such as grape hyacinths underneath is much more effective than a hedge of free-growing forsythia at the end of the plot. They should be planted in small groups of three plants at most. Another challenge is to bridge the remaining garden season after forsythia flowering with other suitable flowering shrubs or perennials. The forsythia are then hardly noticed optically, because they can come up neither with their growth form nor with special leaf decoration. The shrubs are therefore very well suited as background planting for perennial beds, which already take over the flower sceptre from mid-April onwards. Low forsythia varieties such as ‘Week-End’ are occasionally cultivated in plant tubs due to their robust nature. Their rather short flower appearance in spring, however, does not justify such a use and the associated higher maintenance effort.
At Easter Forsythia branches are often used for decoration and for flowering Easter branches. If you cut the branches on Barbara Day (4 December), they will bloom on time for Christmas.
The three main varieties ‘Beatrix Farrand’, ‘Lynwood’ and ‘Spectabilis’ differ only marginally in their characteristics. Beatrix Farrand’ shows the strongest growth and forms strong, somewhat stiff shoots with relatively large flowers and leaves. The flowers of the variety ‘Lynwood’ show a bright yellow with strong luminosity, those of the variety ‘Spectabilis’ are rather dark yellow. Week-End’ is a compact, only 1.5 to 2 metre high variety with relatively bright flowers.
The propagation of forsythia is child’s play, because all varieties reliably form roots as cuttings. The cuttings method is preferred for the higher varieties, while the weaker varieties are usually propagated in early summer by slightly woody cuttings.
Diseases and pests
Forsythia is quite robust and less susceptible to disease in sunny locations with sufficient soil moisture. Sometimes in spring the Monilia drought occurs, which otherwise mainly attacks sour cherries and some ornamental cherries. Cut out infected twigs early and generously from the crown. Powdery mildew is also a more common fungal parasite, but does not cause serious damage. As far as animal pathogens are concerned, one must expect thickmouth weevils and aphids in particular.
In an interview with our store editor Dieke van Dieken, plant doctor René Wadas reveals his tips against aphids.Credits: Production: Folkert Siemens; Camera and Editing: Fabian Primsch
Forsythia in the our store-Shop
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.