Shrub · Oleaceae
Border Forsythia
Forsythia × intermedia
Plant it for the first burst of yellow that opens long before anything else wakes up in spring.
Full sun
Every 7–14 days
USDA 5–8
8–10 ft · 2.4–3 m
Overview
Forsythia opens its flowers on naked wood. In early spring, before a single leaf unfolds, the bare brown branches break out in rows of bright yellow bells, small blooms strung the length of the stems while the rest of the garden is still grey. It is a member of the olive family that grows fast into a big, arching mound, its long canes curving up and outward in the loose habit that has anchored shrub borders for generations.
Look closely and the structure is all reach and arch. The stems shoot up and bend over in long, supple lines, and they shrug off clay, sand, poor ground, and city soil while they do it, holding up through hardiness zones 5 through 8 and riding out a dry spell once rooted. The one thing the wood demands to flower is sun. Set in shade, the canes turn leafy and green and skip the gold that defines the plant.
The shrub builds to a real mass. A mature plant stands 8 to 10 feet (2.4 to 3 m) tall and throws its branches even wider, and the lowest canes root the moment their tips press into the soil, weaving the plant into a thicket if left alone. After the bells fade, paired green leaves take over the same stems that just carried the flowers. Give it room to arch and one trim a year, and the framework stays open and clean.
Care
The short version: full sun draws the heaviest run of yellow bells, almost any well-drained soil holds the roots, even moisture carries it through establishment, and one cut a year right after the flowers fade keeps the canes open.
Light
The canes carry the most yellow bells in full sun. Forsythia still grows in partial shade, but each hour of shade thins the flowers, and a shaded shrub puts out green leaves where the gold should be.
Water
The roots want regular water through the first year while they take hold in the soil. After that the plant largely fends for itself, taking short dry stretches and asking only for medium, even moisture, about one deep soak every 7 to 14 days in dry weather. Standing water around the roots invites rot.
Soil
Forsythia roots into clay, loam, sand, and even tired urban ground without complaint. What the roots need is loose, well-draining soil in the 6.0 to 8.0 pH range, not a rich bed.
Temperature
The wood is cold-hardy from about -20°F to 95°F (-29°C to 35°C). The canes themselves ride out hard winters, but the small flower buds clustered along them take damage once the cold drops below roughly -5°F.
Humidity
Plain outdoor air suits the foliage, so there is no humidity figure to chase. Good airflow through the branches matters more, since crowded, damp leaves are where the spots of leaf spot first appear.
Feeding
Forsythia feeds light. A balanced shrub fertilizer or a little compost in early spring is all the canes need, and overfeeding pushes leafy green growth in place of flowers.
Pruning
The annual cut comes right after the flowers fade. The oldest, thickest stems are thinned out at the base, and the whole shrub is cut back near the ground every 3 to 4 years to push fresh canes. A cut past mid-July strips the new flower buds, since they form on old wood.
Repotting
Forsythia is a landscape shrub and seldom sits in a pot. In a container, its roots need repotting only when they circle and mat against the walls, water runs straight through, or new growth stalls.
Size & spacing
The plant fills out broadly. A mature forsythia stands 8 to 10 feet (2.4 to 3 m) tall and arches even wider, near 10 to 12 feet (3 to 3.7 m), so the canes need open room to curve out without tangling into the next plant.
When to plant
Forsythia times its show to early spring. New plants go into the ground in spring or fall once the soil works and hard frost has passed, the bright yellow bells open along bare stems in March and April ahead of any leaf, and the single yearly cut follows the moment those flowers begin to fade.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall, after the ground is workable and the threat of hard frost has passed.
- Harvest: Early spring (March to April), before the leaves emerge.
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
Forsythia is a tough shrub, so the canes rarely give real trouble, and what does show up traces back to a poor site or a cut made at the wrong time. The signs below read off the plant itself, leaf, stem, and root. Match what you see, then treat the cause behind it.
Dark, soft roots under a wilting shrub
A forsythia that goes limp and fades in waterlogged ground is most often hollowed out by Phytophthora root rot, which leaves the roots dark, soft, and mushy to the touch. Small beadlike knots and swellings strung along the roots instead reveal root-knot nematode, and both worsen where water sits in dense, packed soil. Lift a failing plant and the roots show it at once, dark and collapsing or studded with knots. Open the drainage, ease back the water, and where a shrub is too far gone, pull it and start over on a raised, free-draining site.
Fix:
- Improve drainage and reduce watering
- Remove severely affected plants
- Replant in a raised, well-drained site
Bare stems that stayed bare
When the branches stay plain and brown instead of breaking into color, the cause is usually pruning at the wrong time. The flower buds sit in small paired clusters along the old wood, so any cut made after mid-July shears them off before they can open. Deep shade leaves the stems sparse as well, and a savage winter can kill the buds outright once the cold sinks below about -5°F (-21°C). Prune as soon as the flowers fade, set the shrub in full sun, and pick a cold-hardy cultivar where the buds would otherwise freeze.
Fix:
- Prune only immediately after flowering, never in summer or late winter
- Move or limb up nearby plants to give the shrub full sun
- In cold regions choose hardier cultivars such as Northern Sun or Meadowlark
Spotted leaves and shriveled stem tips
Discrete marks scattered across the leaf surface are the signature of fungal leaf spot, while tips that have gone sunken, dry, and dead point to stem dieback or canker, a problem a drought-stressed plant invites. The base is worth a look too, since rough, woody swellings clustered there are the rough-knuckled lumps of crown gall. Cut the dead and cankered wood back until the exposed surface is clean green tissue, wipe the pruner blades between cuts, and thin the tangle so air slips through it. Watering low at the soil keeps the leaf surfaces dry and gives the spores no film of moisture to settle into.
Fix:
- Remove and discard affected leaves and prune out dead or cankered wood to healthy tissue
- Disinfect pruners between cuts
- Improve air circulation by thinning the shrub
- Water at the base to keep foliage dry
Toxicity
For homes with pets and children the verdict is plain: forsythia is non-toxic across the board. The ASPCA lists it safe for dogs, cats, and horses, and the plant holds no poisonous compounds in leaf, stem, or flower. The yellow blooms taste bitter, which keeps most animals from chewing more than a sample.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A cat is safe with this shrub. A bite taken from a leaf or a yellow flower causes no poisoning, and the bitter taste of the bloom turns most cats away before they swallow much.
Dogs None
A dog can push through the branches or chew a stem with no harm. The worst a large mouthful of any plant matter might bring is a brief, mild stomach upset that settles on its own.
Horses None
Listed as non-toxic to horses, so foliage cropped from the shrub carries no poisoning risk.
Rabbits Safe
No toxic compounds in the plant threaten a rabbit, so a low stem within reach is no danger. The bitter flowers usually cut the browsing short anyway.
Livestock Safe
Cattle, goats, and sheep can share a pasture edge with forsythia without poisoning concern.
Birds Safe
Birds that grip the arching stems or peck at the leaves and flowers face no toxic hazard from any part of the shrub.
People Safe
Safe to plant where children play and safe to prune bare-handed, since nothing on the shrub is poisonous. Washing your hands after handling any garden plant is still good practice.
No special handling required; the flowers are bitter, which discourages nibbling. Wash hands after pruning as a general practice.
Varieties
Most forsythia in gardens is this hybrid, but the named cultivars differ in size, in cold hardiness, and in how thickly the yellow flowers crowd the stems. A few stand out enough to know by name.
Lynwood (Lynwood Gold)
An upright cultivar grown to a standard, its bright yellow flowers spaced in an even rank from the base of each stem to the tip.
Spectabilis
The densest bloomer of the group, its branches packed so thickly in deep yellow flowers that the wood disappears beneath them.
Beatrix Farrand
A vigorous selection that opens unusually large flowers in a deep, saturated canary yellow.
Northern Sun
A cold-hardy cultivar to about zone 4, building a frame near 10 feet tall whose flower buds hold their color through a hard winter.
Gold Tide
A low, spreading dwarf whose stems fan out close to the ground as a groundcover or across a bank or slope.
Companions
Forsythia pairs well with early bloomers that pick up where its yellow leaves off, and poorly with anything trying to grow in the shade beneath its dense canopy.
Plant near
Daffodils: Yellow daffodils bloom at the same time and echo the forsythia's early-spring color at ground level.
Lilac: Lilac flowers shortly after forsythia, extending the shrub-border bloom season; both share full-sun, well-drained conditions.
Keep apart
Turfgrass directly beneath the canopy: The dense arching canopy and surface roots shade and compete with lawn grass, which struggles under the shrub.
How to propagate
Few shrubs copy themselves this readily. A cut length of forsythia roots from its base, and any low cane that touches the soil roots where it lands, so a single plant turns into many.
Stem cuttingsEasy
Late spring to summer · 4 to 8 weeks to root
A cut length of forsythia stem roots with little fuss. Take soft, green softwood cuttings in late spring or early summer, or firmer semi-hardwood cuttings later in the season, and most push new roots from the cut end within 4 to 8 weeks.
LayeringEasy
Spring through summer · One growing season to root
Where an arching branch bows down and rests against the soil, it sends roots from the point of contact on its own. Pin a low stem to the ground any time from spring through summer, let it root over a full growing season, then cut it from the parent and lift the rooted length as a new plant.
Myths
Forsythia should be cut back hard in late winter to make it bloom better.
A hard cut in late winter or summer slices off the flower buds, which sit clustered along the previous year's wood. Heavy pruning at the wrong moment leaves the stems thin or bare of bloom come spring. Wait until the flowers fade, then prune, and the small buds set for next year stay on the wood.
Forsythia berries and flowers are poisonous to pets and children.
The ASPCA lists Forsythia, or Golden Bells, as non-toxic to dogs, cats, and horses, and it counts as safe around children too. No toxic principles sit anywhere in the plant, and the bitter taste of the yellow flowers turns browsers away on its own.