Forsythia

The two weeks of yellow that open the gardening year across most of the country - fast, cheap, tough, and almost unkillable. Its two problems are self-inflicted: it is nearly always planted somewhere too small and then sheared, and it is pruned in spring, which removes the flowers it formed the summer before.

Full sun and almost any soil that drains. The decisions that matter are made before planting: allow the full 8-10 foot width, and in zones 3-4 buy a flower-bud-hardy cultivar, because ordinary forsythia stems survive northern winters while its flower buds do not.

Forsythia is not fussy. Full sun gives the heaviest bloom (it flowers in part shade, more thinly), and it grows in clay, in poor ground, on slopes, and in urban conditions that defeat better-mannered shrubs. It wants nothing from you in the way of feeding — high nitrogen just produces more whippy growth you will have to cut out later. Plant in spring or early fall, water weekly through the first summer, and from the second year on it is essentially drought-tolerant.

Two decisions are made before you dig, and neither can be fixed afterwards. The first is space: a border forsythia reaches 8-10 feet tall and 10-12 feet wide, and squeezing it into a narrow bed condemns you to shearing it forever. If the space is small, buy a genuinely compact cultivar rather than a standard one you plan to control. The second is flower-bud hardiness in cold regions. The stems of F. x intermedia survive to about -25°F, but the flower buds die at roughly -10 to -15°F — so in zones 3, 4, and colder parts of 5 the shrub leafs out every spring and flowers only along the bottom foot, where snow insulated the buds. The cultivars bred at northern universities ('Meadowlark', 'Northern Gold', 'New Hampshire Gold') hold their buds to around -30°F and are the only sensible choice there.

Prune within a month of the last flower, with loppers, never with a hedge trimmer - and renew a third of the oldest canes to the ground each year. Beyond that, sever the branch tips that root themselves, and leave the shrub alone.

Two rules cover forsythia care completely. The first is timing: it flowers on wood formed the previous summer, so all pruning happens in the few weeks after bloom and at no other time of year. Prune in winter or early spring, as most gardeners instinctively do, and you have removed the flowers. The second is method: prune with loppers, one cane at a time, and never with a hedge trimmer. Shearing cuts off the flowering tips, forces a dense twiggy shell that shades out the interior, and turns an arching fountain into a green box that blooms only around its outside. Almost every disappointing forsythia in the country is a sheared one.

The maintenance that actually works is renewal: each year after bloom, cut a third of the oldest, thickest canes off at ground level and leave everything else untouched. The shrub is then permanently rebuilt from young arching wood, which is also the wood that flowers hardest. A neglected thicket can be cut to 4-6 inches all over in early spring — it regrows with astonishing speed and costs you exactly one season of bloom. The one other job is self-layering: any arching tip that touches soil roots there and becomes a new plant, which is how one shrub becomes a thicket and how forsythia escapes into hedgerows and stream banks. Walk the drip line a couple of times a year and cut off the rooted tips — or pot them up, since they are free plants.

Cut generously while it blooms - on this shrub, cutting flowering branches is pruning at exactly the right moment. And from mid-February, once the buds have had about six weeks of cold, cut bare branches and force them into bloom indoors in one to three weeks.

Forsythia is the most generous cutting shrub in the spring garden, because taking flowering branches is the correct pruning, done at the correct moment. Cut long arching stems back to a junction rather than snipping tips, take them in the cool morning, strip anything below the water line, and split the bottom inch of the woody stem so it can drink. A week or so in the vase is typical.

The better trick is forcing. Forsythia buds need roughly six weeks below 40°F to break dormancy, which in most of the country means they are ready by mid-February. Cut branches a foot or two long on a mild day, recut the ends at a sharp angle indoors, split the base, and stand them in cool water in a bright room that is not hot — warmth forces them faster but the flowers are poorer and shorter-lived. They open in one to three weeks, and the closer to natural bloom you cut, the faster they go. Change the water every few days. Cutting a handful of stems every fortnight from mid-February gives you a rolling indoor spring that runs right up to the outdoor bloom, and every branch you take is a branch you would have pruned anyway.

Nothing here stores - the value is in staggering the cuts. Take branches every couple of weeks from mid-February for a rolling indoor bloom, hold cut stems cool and out of sun, and expect about a week from any single vase of flowers.

There is nothing on a forsythia to put away for later, so the useful skill is staggering. Instead of cutting one big armful in February, cut a handful of branches every couple of weeks: the earliest take three weeks to open, the later ones a few days, and the sequence carries indoor flowers from midwinter straight into the outdoor bloom. Branches waiting their turn can be held in a bucket of cool water in an unheated garage or a cold porch, which slows them right down.

Once open, keep the vase cool and out of direct sun, recut the stems every few days, and change the water — woody stems foul it quickly. About a week is a fair expectation, less in a warm room. Dried forsythia keeps neither colour nor form well enough to bother with, and the flowers have no culinary use. If you want to keep something from the shrub, keep a plant: a rooted branch tip lifted from the drip line is a free forsythia that will be flowering within two or three years.

Close to the easiest woody plant there is. Branch tips root themselves wherever they touch soil - lift one and you have a new shrub - and cuttings taken at almost any season strike readily. Seed is not worth it, since the garden hybrids will not come true.

Forsythia propagates itself whether you want it to or not. Tip layering is the whole method: an arching branch that rests on the soil roots at the tip within a season, and lifting that rooted tip with a spade in spring or fall gives you a complete new shrub for nothing. If you want to encourage it, bend a low branch down, wound the underside lightly, pin it into the soil, and leave it a season. This same habit is why forsythia spreads into thickets and turns up along stream banks and hedgerows where nobody planted it — it is worth cutting off the tips you did not intend.

Cuttings are almost as easy. Softwood cuttings taken in early summer root in two or three weeks in moist mix under a humidity cover, and hardwood cuttings stuck outdoors in late fall root over winter with essentially no attention. Rooting hormone helps and is not required. Division of a suckering clump works too. Seed is the one route not worth taking: the garden hybrids are crosses and will not come true, garden plants set little fruit anyway, and seedlings take years to reach flowering size. Named cultivars are propagated vegetatively for a reason, and a few recent introductions are patent-protected against propagation — check the tag before you multiply a new one for friends.

Named for William Forsyth, royal gardener and a founder of the RHS; the garden plant is a chance hybrid of two east Asian species raised in a German botanic garden around 1878. One parent, Forsythia suspensa, has been a major Chinese medicinal herb, lian qiao, for well over a thousand years.

The genus honours William Forsyth (1737-1804), a Scottish gardener who ran the royal gardens at Kensington and St James's and was one of the seven founders of what became the Royal Horticultural Society. The plants themselves are east Asian: Forsythia suspensa was collected in China and reached Europe in the 1830s, and F. viridissima followed from China in the 1840s by way of Robert Fortune. The shrub in nearly every American yard is neither — it is F. x intermedia, a chance cross between the two that appeared in the Göttingen botanic garden in Germany around 1878 and turned out to be better than either parent. Nurseries selected from it heavily; 'Spectabilis' arrived in 1906 and 'Lynwood Gold', found as a sport in a garden in Northern Ireland, in the 1930s.

Long before any of that, F. suspensa was a staple of Chinese medicine. Its dried fruit, lian qiao, appears in the earliest surviving Chinese materia medica and remains one of the most-used herbs in the tradition today, typically in cold-and-fever formulas. That is a documented history rather than an invitation: garden hybrids rarely fruit, species identity and preparation matter, and this belongs to trained practice rather than to a landscape shrub. The 20th-century American chapter is less romantic and more useful — northern universities spent decades breeding for flower-bud hardiness, producing 'Meadowlark' (a joint release from the Dakotas and Minnesota), Agriculture Canada's 'Northern Gold', and the University of New Hampshire's 'New Hampshire Gold', so that gardens in zone 3 could finally see the whole shrub bloom.

Flowers only along the bottom, to a sharp line, means winter killed the buds above the snow. Flowers only around the outside of a dense shell means it has been sheared. No flowers at all usually means it was pruned between midsummer and spring - which is to say, at the wrong time.

Flowers only on the lowest foot or two, stopping at a sharp horizontal line: the classic northern failure. The stems came through winter fine but the flower buds above the snow line died, which happens at about -10 to -15°F on ordinary border forsythia. Nothing can be done to the existing plant; the answer is a flower-bud-hardy cultivar, or a more sheltered position. No flowers at all on a healthy green shrub: almost always pruning at the wrong time — the buds form in summer, so any cut from midsummer to bloom removes them. Skip a year of pruning and they come back. Deep shade and, occasionally, heavy nitrogen do the same thing.

A dense twiggy shell with flowers only around the outside: it has been sheared. Renewal-prune a third of the oldest canes to the ground each year after bloom, or cut the whole shrub to 4-6 inches in early spring and start again — it regrows fast. Rows of small dark sunken spots on new leaves in early summer: four-lined plant bug — cosmetic, over by midsummer, and not worth spraying. Knobby woody swellings clustered on older stems: forsythia stem gall — prune affected stems out below the galls and disinfect the blades between cuts. New shrubs appearing around the parent: branch tips have rooted where they touched soil; lift or cut them off unless you want a thicket. Whole plant wilting in wet, heavy ground: root rot — a forsythia will forgive almost any soil that drains and none that does not.

Zones 5-8 is straightforward forsythia country. Zones 3-4 need flower-bud-hardy cultivars or the shrub blooms only below the snow line. Zone 9 and the Gulf run short of the winter chill it needs, and warm-spell dehardening costs the mid-Atlantic and Southeast whole bloom years.

Zones 5-8 are simple: plant it, give it room, prune after bloom. Zones 3-4 are the interesting case, because forsythia's stems and its flower buds have very different hardiness — the wood survives, the buds do not, and the result is a shrub that leafs out perfectly and flowers only where snow buried it. Buy a bud-hardy northern cultivar ('Meadowlark', 'Northern Gold', 'New Hampshire Gold') and the problem disappears. Siting out of desiccating winter wind, and against a wall that holds a little warmth, buys a few degrees more.

Further south the constraint flips. In the mid-Atlantic and upper Southeast, the trouble is not depth of cold but volatility: a warm February spell dehardens the buds, and a sharp freeze afterwards takes the bloom — which is why some years are spectacular and others are green. Below about zone 9, and along the Gulf, forsythia runs short of the winter chilling it needs and flowers thinly if at all; a southern garden is better served by a plant that wants the heat. One last regional point that applies everywhere: forsythia is a two-week plant with little wildlife value — it blooms too early and too poorly to feed many native pollinators, sets almost no fruit for birds, and supports few insects. If you want an early yellow shrub that also does ecological work, look at spicebush or a native witch-hazel, both of which flower even earlier and both of which have their own entries here.