When to Plant Goldenrod: Fall Sowing, Cold Stratification, Clumping Types and Dividing Solidago

Goldenrods (Solidago) are a genus of about 138 daisy-family perennials, mostly native to North America (NC State). Iowa State counts more than 120 species, over 70 of them native to the US and Canada. Heights range from about 1 foot to 8 feet (NC State), and most bloom in late summer and fall with small yellow flowers packed into wands, plumes or flat clusters (Iowa State, NC State). Every source we read makes the same point about allergies: goldenrod pollen is heavy and sticky and carried by insects, and the hay fever blamed on it comes from wind-pollinated ragweed, which blooms at the same time (Iowa State, NC State, Dole, Prairie Moon, Almanac, Wildflower Center).

When to plant goldenrod

Use our planting calendar to find your frost dates. The sources agree that most goldenrod seed wants a cold spell, but they disagree on how much: the Almanac and Prairie Moon use about 60 days, while Dole's cut-flower schedule allows up to 10 weeks at 40°F and notes that some species sprout in 2 to 3 weeks at 68 to 72°F with no chilling. Our reading is that fall sowing outdoors is the simplest route, because winter takes care of the chilling. The Wildflower Center warns that germination of rough goldenrod is often poor and suggests sowing thickly. Prairie Moon expects seed-grown plants to flower in their second or third year.

How to plant goldenrod

Plant nursery starts at the same depth they grew in the pot, loosen circling roots and water them in (Almanac). Iowa State's short cultivars, such as 'Golden Fleece' at 15 to 18 inches and 'Golden Baby' at 18 to 30 inches, suit smaller beds; tall prairie species are best in naturalistic areas, it says.

Watering, feeding and dividing

• Water the first season. The Almanac waters young plants weekly if rain is short; after that most goldenrods are drought tolerant (Iowa State, Almanac).
• Skip fertilizer in the ground. The Almanac says garden goldenrod needs none, though potted plants benefit from monthly feeding.
• Deadheading is optional. NC State says it can bring more blooms; the Almanac calls it unnecessary. Cutting seed heads also limits self-sowing (our reading).
• Divide every 2 to 3 years for spreading types and every 4 to 5 for clumpers, in early spring as growth starts (Iowa State).
• Staking is rarely needed for 'Fireworks', whose stiff stems may lean but seldom fall (Wisconsin).

Goldenrod in containers

The Almanac includes patio containers among its uses and suggests feeding potted goldenrod monthly. Iowa State's shorter cultivars, such as 'Golden Fleece' and 'Golden Baby', are the obvious picks for a pot. Our reading is to use a large pot with drainage holes, since most goldenrods have deep roots (Prairie Moon cites a study averaging about 8.5 feet for Solidago), and to water more often than you would in the ground (GardenPal reasoning).

Fall and winter

• Leave seed heads standing. Minnesota BWSR says stiff goldenrod's seed heads last into November or December and feed chickadees and finches; NC State says birds are fond of the seeds.
• Fall is planting and sowing time. Get plants in at least 6 weeks before the ground freezes, and sow seed any time before freeze-up (Almanac).
• Collect seed when it turns white. The Wildflower Center checks rough goldenrod in October: grayish nutlets need more time, and plump ones are the viable seeds.

Pests and problems

Goldenrods have few serious problems (NC State, Iowa State, Wisconsin). NC State lists rust, powdery mildew and leaf spot, and Dole names goldenrod rust and powdery mildew and says not to plant goldenrod near pines, which are alternate hosts for the rust. Wisconsin says 'Fireworks' resists both mildew and rust but notes spider mites and lace bugs on some goldenrods. NC State lists shining flower beetles, Asiatic garden beetles and leaf-footed bugs among common insect visitors. Most sources call goldenrod deer resistant (NC State, Almanac), and NC State rates rough goldenrod as moderately so. Spreading is the most common complaint, so choose the species with care (Iowa State).

Goldenrod around the vegetable garden

Goldenrod is one of the late flowers we list in flowers that attract beneficial insects. The Wildflower Center, citing the Xerces Society, credits it with special value to native bees and honey bees and with supporting conservation biological control. Minnesota BWSR adds that soldier beetles and hoverflies drawn to stiff goldenrod also prey on pest insects, and that monarchs feed on it before migrating. Because it blooms as most crops finish, plant a clump-forming goldenrod at the sunny back edge of the plot, not in rich, irrigated beds where spreaders run (our reading). Wisconsin and NC State both pair goldenrod with fall asters; see when to plant asters. Other good neighbors include liatris, black-eyed Susans and coneflowers.

Frequently asked questions

When should I plant goldenrod?

In spring or early fall, at least 6 weeks before the ground freezes (Almanac).

Does goldenrod seed need cold stratification?

Most species do. The Almanac and Prairie Moon use about 60 days of cold, moist treatment; Dole says some species need up to 10 weeks and a few need none. Sowing outdoors in late fall lets winter do it.

Does goldenrod cause hay fever?

No. Its pollen is heavy and sticky and is carried by insects; the wind-borne pollen behind fall hay fever comes from ragweed (Iowa State, NC State, Prairie Moon).

Will goldenrod take over my garden?

Some species will. Canada and late goldenrod spread by rhizomes, while showy goldenrod and sweet goldenrod form clumps (Prairie Moon, Almanac). Iowa State divides spreaders every 2 to 3 years.

Which goldenrod is best for a garden bed?

Clump formers such as 'Fireworks' (Wisconsin, Iowa State) or short cultivars like 'Golden Fleece' and 'Golden Baby' (Iowa State).

When should I divide goldenrod?

In early spring as growth begins (Iowa State). Minnesota BWSR also moves stiff goldenrod clumps in late fall.