forsythia (Forsythia × intermedia), photographi

How to Grow Forsythia

Forsythia × intermedia · Zones 5-8

Forsythia is a perennial grown for its yellow blooms, which open in spring and return year after year. It's hardy across USDA zones 5 through 8. Its spring flowers are a modest draw for honeybees.

Forsythia — the short answer

Forsythia: grown in zones 5–8, full sun, pH 5.5–8.

USDA zones
5–8
Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
Soil pH
5.5–8
Growable Ground Plant Database
Sun
Full Sun
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — each tile names its own row's source, because per-field provenance varies.

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What Forsythia is

Forsythia grows as a perennial and reaches around ten feet at maturity. It blooms yellow in spring.

How to grow Forsythia

Forsythia grows in USDA zones 5 through 8. Forsythia does best in full sun — at least 6 hours of direct sun a day — and soil from pH 5.5 to 8, on well-drained ground. It needs a growing season of at least 120 frost-free days and about 500 hours of winter chill, which is why climate matters as much as soil.

USDA Zones

5-8

USDA PHZM 2023

Soil pH

5.5 - 8

Growable Ground Plant Database

Sun

Full Sun

Growable Ground plant catalog

Drainage

well (dry spells)

Growable Ground plant catalog

Mature Height

10 ft

Growable Ground plant catalog

Chill Hours

500+

Winter hours below ~45°F it needs to fruit — too-mild winters can leave it bloom-shy.

Growable Ground plant catalog

Frost-Free Days

120+

The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.

Growable Ground plant catalog

  1. Start the season right

    Plant forsythia in full sun with at least 6 hours of direct sun. It grows in the cool halves of the year, so sow it in spring or late summer rather than waiting for midsummer heat.

  2. Match the soil

    Forsythia prefers pH 5.5 to 8 (Growable Ground Plant Database). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.

  3. Water steadily

    Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.

  4. Harvest at its peak

    Cut forsythia blooms in the cool of the morning, just as they open, for the longest display.

Where Forsythia thrives

Forsythia is hardy across USDA zones 5 through 8. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.

A USDA zone is a 10°F band of average annual extreme winter minimum, so zones 58 spans average winter lows from -20°F to 20°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 19 outright and splits 31 more down the middle — and which side of that line your land sits on changes the answer.

Zones 5–8 highlighted on the USDA national hardiness zone map

Zones 5–8·Where Forsythia growsOpen map →

Where Forsythia stands, state by state

Forsythia is rated for zones 58 — a cold floor USDA puts at -20 to -10°F. Across the 50 states and DC, 19 sit fully inside that band, the line runs through 31 more, and 1 sits outside it — and inside every split state, the same line runs on at county grain.

Fully inside zones 5–8

19 states

3 of 19 shown

The line runs through

31 states

3 of 31 shown

Forsythia’s band covers part of each of these states — which side of the line your county sits on changes the answer, and each state page draws it.

Outside zones 5–8

1 state

Winter cold is the limit here — the same plant often works in a container that comes under cover. Each link is that state’s own growing hub.

State zone extents: USDA Plant Hardiness Zone Map (PHZM) 2023. A zone is a 10°F band of average annual extreme minimum temperature, so a state that splits the band contains the boundary — its own page draws the county line, and a parcel report resolves which side your land sits on.

What grows around Forsythia

In rotation planning, forsythia counts as a Other — beds recover best when other crops don’t follow each other in the same spot year over year. (Growable Ground derivation — crop-rotation group from botanical family)

Good to know

Good news for pet owners — forsythia isn't known to be toxic to dogs or cats. (Source: ASPCA.)

Forsythia offers low value to bees and other pollinators.

Your land is one point inside Forsythia's range

This page resolves to the species. Your state page draws the county line, and a report reads the parcel — the soil pH, drainage, sun, and frost dates on your exact ground, which no species average can see.

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See if Forsythia will thrive on your land

Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether forsythia actually takes — we score it against the real conditions at your address.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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How we know this about Forsythia

The figures above are cited per row, not per site: the pH band names this plant’s own source column, the three temperature figures each carry their own, and days-to-maturity cites the publication that actually lists it. All of it comes from the Growable Ground Plant Database — a compilation over FAO ECOCROP, USDA PLANTS, and university Extension sources, published openly with per-field provenance.

Grounded inUSDA PLANTS DatabaseUSDA PHZMASPCA

Frequently asked questions

Can I grow Forsythia in my zone?

Forsythia grows in USDA hardiness zones 5 through 8 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.

When should you plant Forsythia?

Forsythia is a cool-season crop, so it goes in during the cool halves of the year — early spring, and again in late summer for a fall planting — rather than at the height of summer heat. Your local frost dates set the exact window — a Growable Ground report reads them for your address.

How much sun does Forsythia need?

Forsythia needs full sun — a spot that catches at least 6 hours of direct summer sun a day. In more shade it still grows, but usually gives a smaller, later crop. The catch is that a yard rarely gets even light everywhere — a fence, the house, or one tall tree can quietly take those hours. A Growable Ground report reads the real sun-hours across your land, canopy and buildings included, so you can pick the brightest bed before you plant.

What soil does Forsythia need?

Forsythia prefers soil pH 5.5 to 8, on well-drained ground (Growable Ground Plant Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.

Does Forsythia attract pollinators?

Yes — forsythia's flowers are a modest nectar source for honeybees.

Is Forsythia safe for pets?

Forsythia is not known to be toxic to dogs or cats based on available data. Always supervise pets around new plantings. (Source: ASPCA.)