As one of the first plants the border forsythia brings some colour to the garden in spring. The ornamental shrubs are very popular with their yellow flowers, which are formed in abundance on the branches already in April. It decorates many gardens, mostly as a robust hedge plant. Forsythia are not very demanding, but they do need some care.
- Plant family: Oleaceae
- Hybrid from two species of the genus Forsythia
- Species: Forsythia x intermedia
- Trivial names: border forsythia, common forsythia, showy forsythia, golden bells forsythia
- Origin: Eastern Europe and Asia
- Height: 2 to 3 meters
- Growing width: 1.5 to 2 meters
- Growth speed: 30 to 60 cm per year
- Flower: strong yellow in April
- Leaves: lanceolate, fresh green, yellow in autumn
The origin of the Forsythia lies in the south-east of Europe and Asia. A certain kind of Forsythia is traded and designated as border forsythia: the Forsythia x intermedia. From April to May, numerous bell-like flowers of golden yellow colour are formed on the branches, which are up to three meters long.
This is why it is sometimes also referred to as golden bells forsythia. The plant belongs to the Oleaceae family. In nature you’ll search in vain for the popular border forsythia, because this flowering shrub is a hybrid.
It was bred from two other species of the Forsythia family and remains sterile. The golden flowers of the ornamental shrub do not form pollen, and therefore do neither attract bees nor other insects that can be fed on their nectar.
If plant and soil conditions are right, established plants can grow with very few maintenance measures. The border forsythia is a robust flowering shrub, which is suitable for almost every garden.
Concerning the demands on its location, the border forsythia is absolutely undemanding and adaptable. In a sunny location, the showy forsythia will thrive just as good as in a rather shady place. The shrub can therefore be planted almost anywhere in the garden, depending on nothing else than your decorational wishes. The best flowering is to be expected in a sunny and warm location.
- light demand: sunny to half-shaded
- is usually used as a hedge plant
- also suitable as a solitary plant
- bucket planting is possible
As long as the soil is not extremely calcareous or prone to waterlogging, this flowering shrub is very tolerant to all soil conditions. The border forsythia grows easily on nutrient-rich but also on poor soil. Perfect growth conditions are provided by well drained garden floors with a medium nutrient content.
- medium humus content
- well water permeable
- slightly damp to moderately dry
Basically, these pretty flowering shrubs can be planted all year round. Only frost periods and high summer periods are less recommended planting times. However, this spring flower will grow best when it is planted into the soil in early spring.
Planting into a bed
Despite the border forsythia being winterhardy under virtually any conditions, it does need a little time to grow properly. The best planting time for the shrub begins as soon as the soil is frost-free in spring. It is advisable to loosen the soil in advance with the rake or a spade and to free it from stones, weeds and old roots.
- enrich sandy soil with compost or humus
- mix heavy soils with sand or grit
- planting hole: two times the root ball width and depth
- planting distance for a solitary brush: 80 to 100 cm
- planting distance for hedges: 50 cm
- for wet soil, create a drainage with chippings or sand
- mix some mature compost to the excavation
- generously water the rootball before planting
- fill in the soil and press it gently
- slur the soil with water
Planting into a pot
The planting of a Forsythia x intermedia into a pot is very similar to the open-air planting. The pot must be of sufficient size and contain drainage openings at the bottom. A saucer is better than a cachepot, because the excess water is easier to recognize and can be poured away.
- place a clay scraper or grid on the drainage opening
- fill in a drainage of coarse sand, chippings or expanded clay
- use high-quality bucket substrates for flowering shrubs
- alternative: a mixture of humus soil with low peat content, sand and grit
Generally, the replanting of large shrubs is rather difficult, because the root ball can be damaged. If a change of location is indispensable, a preparatory action is necessary in spring. For this purpose the roots are parted off with a spade at a distance of about 40 cm around the plant. This way, new, fine roots are formed.
Nevertheless, enough undamaged roots will remain so that the shrub does not die. In the following late autumn to early spring (during the winter rest) the border forsythia can then be lifted out in a radius of about 60 cm and be replanted to a different place in the garden. A frost-free day should be chosen.
If the border forsythia is well rooted in the outside soil, it must be watered only in long dry periods. Pour the shrub only when the surface of the soil is already well dried. The showy forsythia is best poured in the early morning or evening hours. Since the shrub only forms shallow roots, the water should be supplied slowly, so that it can be sucked up sufficiently from the upper soil layer. In spring, autumn and winter, a free-field border forsythia usually does not require any additional water.
Young plants and tub plants must be poured a little more frequently. Excess pouring water in the saucer is poured out after 10 minutes at the latest, so that no waterlogging can form. If the leaves sag down, this is an infallible indication that the plant suffers from a lack of water.
If a Forsythia x intermedia is planted on nutrient-rich, humus soil or when composting or planting fertilizers have been incorporated into the soil, it does not need any additional fertilizer in the first years. In the following years the border forsythia should be moderately fertilized. In most garden soils, the shrub grows completely without additional nutrients.
If you have planted the border forsythia on sandy or nutrient-poor soil, proceed as follows:
- time: early spring
- in the open air: mix some compost or long-term fertilizer into the soil
- tub plants: Use liquid fertilizer or fertilizer sticks
- re-fertilize in May if needed
- perfect is a fertilizer with NPK ratio 10-10-10 or increased phosphorus content
From September on you should not fertilize this plant, so that the shoots become well wooded to be sufficiently winterhardy.
If you just let your showy forsythia grow as it wants, you’ll be disappointed after some time. After about three years, the bloom will noticeably disappear. To stimulate the growth of the petals, a border forsythia must be cut, not only a little bit at the tips, but rather radically. Many healthy shoots from the previous years are necessary for a rich flowering.
If the border forsythia is blooming and the shrub (hedge) is still in a good shape, only a normal thinning and care cut is necessary as with all other flowering shrubs. Such a thinning should not be done too late in the year. If you cut it in summer or autumn, the fresh shoots and buds may freeze in winter.
- time: immediately after flowering
- choose a cloudy yet rain-free day
- don’t only cut the tips of the shrubs
- old shoots with ramifications should be cut near the ground
- cut off new, very thin shoots just above the ground
- shorten all sick or dead branches until only healthy wood remains
- remove all intersecting or inward growing branches
- reduce overhanging branches by at least one third
- young, strong shoots from the previous year must not be removed
- pay attention to the natural shape
If a border forsythia is not cut for many years in a row, more and more thin branches are formed over time, which do not bear any flowers. In this case, a strong cutback is necessary, because the shrub needs a rejuvenation treatment in order to regenerate itself. In case of diseases a radical measure like this can also help to cure the border forsythia.
- time: winter or spring (before flowering)
- choose a frost-free, slightly cloudy but dry day
- cut back to about 10 to 20 cm above ground level
- leave 4 to 5 healthy, strong shoots
- remove all weak shoots in the following year again
- cut the shoots from the previous year close to the ground
- shorten all other branches to different lengths
In the following spring, the border forsythia will reward the gardener with new flowers. From now on, the cutting should be done again in May after flowering. Depending on the desired height and width, the hedge or solitary shrub is slowly built up until a light annual cut is sufficient to keep the plant in shape.
All available Forsythia varieties are absolutely winterhardy. Older shrubs and Forsythia, which were planted in the spring, will even survive the lowest degrees without any harm. Winter protection is only necessary on plants which have been planted in autumn.
- protect freshly planted border forsythia with brushwood or mulch
- place potted plants on a styrofoam plate
- wrap the bucket with a fleece or foil to be sure
If late frosts occur during the flowering period in spring, the flowers or buds may freeze. Unfortunately, no preventive measure is possible for this case.
A border forsythia is a rather unpretentious flower shrub, which can easily be multiplied with small effort even by untrained hobby gardeners. Since the showy forsythia is a hybrid, it does not form any fruits or seeds. Therefore, a multiplication is only possible vegetatively.
If the flowering is at an end, the time for the annual cutback has come. This is an ideal time to pick a few cuttings for propagation. Just select a few green, healthy branches that are still flexible.
- time: Early summer
- other good times: in July or in winter
- length of the cuttings: 15 cm
- remove the lower leaves (to about 2/3 of the length)
- slightly scrape off the bark on the last two centimeters
- plant them into a pot with a moist substrate
- put them into the substrate to the half of their size
- substrate: cultivation soil, cactus compost or a mixture of garden soil and sand
- location: half-shaded
- temperature: around 20 degrees
To ensure that the cuttings will root well, the substrate should always be kept slightly moist. Waterlogging must necessarily be avoided, because it leads to mold and putrefaction.
Another way to multiply border forsythia is by layers. To do this, you must simply bend a long, possibly overhanging shoot down to the ground. This should be carefully placed into a trench of loosened soil so that the tip looks out at the other end.
- remove all leaves from the branch that is in the ground
- at the lowest point in the soil you should slightly scrape or peel off the bark
- fill the trench with soil again
- fix the layer to the ground with a tent peg
- alternatively you can weight the layer with some heavy object
If the redirected shoot grows longer, it should be attached to a rod immediately so that it can grow upright. After about one year, the layer can then be separated from the mother plant and transferred to a different location.
Forsythia are not particularly susceptible to specific diseases. Nevertheless, you should pay attention to pests and diseases regularly. If illnesses occur, care mistakes are almost always the cause.
Fungi can penetrate into the plant through injuries and wounds. Therefore it should always be strictly ensured that a cutting is only done on rainless days so that the injuries can dry quickly. Smooth cuts with sharp, sterile cutting tools promote wound healing. If the border forsythia is affected by a storm- or hail-damage, the damaged and kinked branches should be cut off in a timely manner. In case of a fungus attack, diseased wood must be cut out as early as possible until only healthy wood remains.
The most common pests that occur on a border forsythia are bugs. In spring they suck on the still rolled leaves, so that ugly holes are showing up in it, as soon as the leaf unfolds. You can not do much against bugs as a gardener, but they do not lastingly damage the plant, but only affect their optical appearance.