Zone: 4 to 8
Soil: Sand to loam
Light: Full sun to part sun
Bloom colour: Yellow
Bloom period: Late summer into fall
Height: 12 inches to 7 feet
Moisture: Often dry to medium
Attracts: Bees, butterflies, beetles wasps and flies.
Notes: Goldenrod is a must in any wildlife garden because it blooms late in season when other flowers are coming to an end and it supports a diverse range of species. It combines well with Asters, which are also late blooming and have complimentary colours. There are a large number of goldenrod species and cultivars to suit any water and soil requirements. Most species are drought tolerant. In a regular garden, you need to be fussy about which species you grow because many goldenrods are too aggressive. Goldenrods look their best in the garden when planted in decent sized groups.
Euthamia graminifolia is a beautiful flat topped goldenrod It flowers in early August and attracts a large number of beneficial wasps. However, like many other goldenrods, it has a spreading fibrous root system which disturbs a lot of other plants when you have to pull it up. It is not suitable in small suburban gardens unless you want to try a large container. Another option, perhaps more suitable for a container, is Euthamia gymnospermoides as it is shorter than E. graminifolia. The common species of goldenrod, Solidago canadensis, which you see growing everywhere, should not be planted in your garden unless you want your garden bed to become a disaster zone.
Instead of Euthamia and other aggressive species, consider flat topped flowerheads that behave well in gardens. Stiff Goldenrod (Oligoneuron rigida) is fairly easy to obtain and is attractive to Monarch butterflies. It has the advantage of being quite versatile in terms of its light and moisture requirements although full sun and slightly dry soil is preferred. Its oblong leaves are much larger than average for a goldenrod and are less scrawny looking. The leaves will be attacked by mildew with too much shade. The stems are fairly stiff and self-supporting but I find it helpful in part-sun to provide a wide tomato cage. It grows about 5 feet in height.
Ohio Goldenrod can be confused with Stiff Goldenrod but it is shorter at 30 inches and the leaves point upwards along the stem. It grows well in well-drained soil but it does like moisture. Its is naturally found close to the great lakes.
Many goldenrods flowers are large terminal clusters that are formed from several one sided clusters (Newcombe, 1977). Solidago rugosa looks like a more typical goldrenrod. It prefers full sun and wet soil. It also grows in clay. I would look for the cultivar "Fireworks" because it grows less than four feet high. It is covered in a thick random spray of flowers. The native species is probably not suitable for most gardens.
Gray Goldenrod (Solidago nemoralis) which does not grow more than two feet high and has a cluster that grows on one side of the stem and bends over. It is suited to dry sunny places with difficult soil conditions. It naturally grows in disturbed areas with reduced levels of competition. Showy goldenrod (Solidago speciosa), and Stout Goldenrod have elegant wandlike terminal clusters. Showy Goldenrod looks fantastic in a garden but it needs dry sandy soil to grow well as it would in savannah conditions. It is one of the last Goldenrods to flower and is covered in bumblebees. In comparison, Stout Goldenrod requires more moisture.
Upland white aster is actually a goldenrod that does well in dry sandy soil and only grows to 18 inches high. It is a plant for the front of the border but its ability to attract pollinators is considerably less than other goldenrods. Silverrod is a goldenrod with socially distanced ray flowers that are also white or cream coloured. It only grows about two feet high and likes sandy soil. It looks surprisingly good en-masse.
In the shade, there are two good choices that both grow less than 3 feet high. Zig-zag Goldenrod has broad egg-shaped leaves and a long terminal cluster of flowers. It grows quite upright. Blue-stemmed goldenrod has a spreading cluster of flowers and alternating flowers along the stem. For shade plants, they are quite good at attracting bees. It is a good plant at the front of the border because it falls over and grows horizontally. These plants combine well with Aster cordifolia. Blue-stemmed goldenrod is more drought tolerant, but there is considerable overlap in the growing conditions. A shady bed of Asters mixed with Goldenrods will give you a wonderful display of flowers in early fall.
Reference: Lawrence Newcomb, 1977, Newcomb's wildflower guide