HARDINESS: Zones 3 to 9
PREFERRED SOIL pH: Neutral to slightly acid
PREFERRED SOIL TYPE: Poor to average, well-drained
PREFERRED LIGHT: Sun
ATTRIBUTES: Late-season golden flowers on shrubby plants; for beds, pots
SEASON OF INTEREST: Late summer and fall
FAVORITES: 'Fireworks', 'Golden Fleece'
QUIRKS: Plant these rapidly expanding perennials 1 ft (.3m) apart
GOOD NEIGHBORS: Aster, chrysanthemum, Joe Pye weed, Russian sage, viburnum
WHERE IT GROWS BEST: Sun; well-drained, poor to average soil
POTENTIAL PROBLEMS: Grows poorly in damp soil; powdery mildew in cool, damp weather
RENEWING PLANTS: Plants live 3-5 years; divide clumps every 3 years in spring
CRITTER RESISTANCE: Good
DIMENSIONS: 1-4 ft (0.3-1.2 m) high 1-3 ft (0.3-1 m) wide
Goldenrod in the Landscape
In true Cinderella fashion, goldenrod has gone from being considered a weed to earning its place as a valued garden flower. It has received a makeover by plant breeders determined to transform the wild thing into a dense, brightly colored flowering perennial with garden-worthy manners. In sun and well-drained soil, goldenrods are extremely easy to grow, settling in and becoming luxuriant sentinels of fall, showering your garden with beautiful golden flower plumes.
Together with other autumn favorites, such as asters, chrysanthemums, and Russian sage, goldenrods bring the season to an end in glowing color. A classic combination is goldenrod and a rich purple-flowered aster, such as 'Purple Dome'.The fleecy yellow goldenrod plumes dramatically accent the yellow button at the center of each aster blossom. Be generous when you plant goldenrod. Because of its lean stature, it is best planted in groupings of 3 or more plants.
If you've avoided goldenrods to keep from sneezing, you need not hold them at arm's length any longer. The truth is that goldenrod pollen is not the culprit that triggers allergic reactions; rather, pollen allergies are aggravated by ragweed (Ambrosia spp.), which is an entirely different family of annual and perennial weeds that flower at the same time as goldenrod.
Garden Worthy Goldenrods
Solidago rugosa 'Fireworks' has a compact clumping habit suited to a perennial border or to placement in front of shrubs. S. sphacelata 'Golden Fleece' is a petite, 12 in (30.5 cm) tall version that carries its cheery golden sprays in tidy pyramids. Tuck it among other plants, employ masses of it as ground-cover, or feature it as part of a container planting.
Like their weedy ancestors, garden goldenrods are not fussy. They thrive in soil with poor to average fertility, and require little water and no fertilizer. In fact, goldenrods grown in overly rich soil are likely to flop over and flower poorly. To promote flowering, however, sun exposure is a must.
Plant goldenrods in spring so that you can enjoy the show the following fall. Dig a hole roomy enough for the plant's roots and untangle the root ball with your fingers before setting it in the hole so that the roots can grow into the surrounding soil. Set plants at least 12 in (30.5 cm) apart.The planting may look puny at first, but it will fill the gaps as it matures.
While remarkably insect free, goldenrod leaves may contract powdery whitish patches of a disfiguring fungal disease called powdery mildew in late summer, when days are hot and nights are cool and damp. Trim off and dispose of affected foliage and thin surrounding plants to promote better circulation, which will in turn discourage the disease.