Zone: 3 to 8
Soil: Sand to loam
Light: Full sun to part sun
Bloom colour: Usually 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.
Plants to avoid:
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. This is a plant that likes moisture so use a container with a water reservoir. If you have a moist spot in a larger space where plants can grow as tney please, then E. graminifolia is an excellent choice.
Another option, perhaps more suitable for a container is Euthamia gymnospermoides as it is shorter than E. graminifolia and does well in dry conditions.
The common species of goldenrod, which you see growing everywhere, include Solidago canadensis, S. altissima and S. gigantea. Many goldenrods flowers bloom in large terminal clusters that are formed from several one sided clusters (Newcombe, 1977).These species should also not be planted in your garden unless you want your garden bed to become a disaster zone.
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. Its height and form make it an attractive goldenrod for the garden but it also has a spreading root system and tends to form colonies. Given its small size and ability to survive in dry sandy soil, it would be a good candidate for growing in a container.
Solidago rugosa is also a spreading goldenrod, but the selection 'Fireworks' spreads only slowly. It will grow in a variety of soils including clay, but it does need full sun and moisture. It is attractive because it is only 4 feet high and it is covered in a thick random spray of flowers. The straight species is probably not suitable for most gardens.
Plants to grow:
Instead of Euthamia and other aggressive species, consider flat topped flowerheads from the genus Oligoneuron. These species behave well in gardens and they have a good sized bloom. 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.
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.
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. The plant has a heavy bloom and is considered to be one of the most stunning goldenrods to grow. In comparison, Stout Goldenrod requires more moisture and is half the size.
One other goldenrod worth planting is Early Goldenrod. It is about 3 feet high and has a typical goldenrod look. It flowers a few weeks before other goldenrods and while it can grow rhizomes, it tends to be a lot less aggressive than other goldenrods.
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 and Aster shortii. 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. These last two goldenrods can spread as well, but I have not found them to be problematic in dry sandy soil.
Reference: Lawrence Newcomb, 1977, Newcomb's wildflower guide
Dry shade - Solidago Caesia
Medium shade - Solidago flexicaulis
Medium sun - Solidago juncea, Oligoneuron ohioensis
Wet sun - Oligoneuron ohioensis
Dry sun - O. rigida, O. album, S. speciosa, S. bicolor