Solidago, Goldenrod: planting, growing, care

Description and botany

Solidago, also called solidage or goldenrod, is a herbaceous perennial belonging to family Asteraceae, like daisies, asters and sunflowers. It is native to North America, especially Canada, and to eastern and central United States where it grows in very varied habitats ranging from mountain areas to dry woods, fresh meadows, sandy fields, fallow land and riverbanks.

The genus includes about 125 species such as Solidago canadensis, or Canadian goldenrod, Solidago rugosa, Solidago gigantea or giant goldenrod. Many botanical species, now considered invasive, are increasingly abandoned (and for some banned from sale) in favour of non-invasive hybrid varieties, such as Solidago ‘Goldenmosa’, ‘Crown of Rays’ (syn. ‘Strahlenkrone’) or species with a much less invasive character, such as Solidago Shortii or Solidago altissima, a tall goldenrod. Solidago virgaurea in turn is widely used for its medicinal properties.

From a more or less running rhizomatous crown, goldenrod forms a dense upright clump, with a flexible, airy habit, sometimes slightly trailing (Solidago ‘Fireworks’) made up of numerous leafy stems from 0.30 m for dwarf forms to 2 m high in flower for the largest goldenrods such as Solidago altissima. Fast-growing, these stems can, depending on species, reach up to 1 m in a single season.

Once well established, this rhizomatous perennial grows quickly to form dense clumps that can become invasive in favourable conditions, but new varieties have moderate development making them suitable for all gardens. They usually need about two years to thicken up and reach full potential.

Solidago vigaurea – botanical illustration

On villous, erect stems, sometimes arching and ramified in their upper part, deciduous foliage unfolds. Leaves lanceolate to linear, with dentate margins, are arranged alternately along stems. Shiny bright green to chartreuse above, they are villous beneath and rough to the touch. Some species have stems of a reddish-purple colour.

Sunny and spectacular, flowering occurs from July to October, depending on climate and variety, bursting from fine foliage like a shower of gold. A myriad of small flowers gathered in light, arching panicles appears at tips of flexible stems. These highly ramified spikes are compact or grouped into pyramids depending on species. All bear tiny mossy heads 5 to 8 mm wide resembling miniature daisies or mimosa, made of five pedunculate lobes all bending together in same direction. They erupt in sprays often gracefully trailing in shades of pale yellow, bright lemon-yellow to golden yellow, hence vernacular name “goldenrod”!

Although unscented, this generous display rich in pollen and nectar is particularly melliferous, attracting pollinating insects right up to onset of winter.

Radiant inflorescences of goldenrods will compose wild, airy summer and autumn bouquets. They can also be dried for inclusion in dried flower arrangements.

These pollinated flowers give way to tiny winged fruits containing very many fine seeds that readily disperse by wind to self-seed where they land.

With its luminous plumes, solidago brings colour and cheer from summer to autumn and fully deserves a place in all natural gardens. Tall goldenrods such as Solidago altissima are planted at back of borders, with other vigorous perennials or on banks of a pond. Dwarf species like Solidago canadensis ‘Gold King’ are reserved for pathside or border edges.

Solidago or goldenrod is also used for centuries in phytotherapy for its medicinal virtues, notably to treat colds, respiratory and renal ailments. Used externally, goldenrod promotes wound healing, hence its Latin name meaning “to consolidate”.

Goldenrod is an edible plant; its flowers, stems and leaves, honey-flavoured, are consumed dried as infusions and herbal teas.

Main species and varieties

Most popular

Our favourites

Solidago Goldenmosa

Part of these new hybrid varieties, more compact, particularly bright and non-invasive. Adapts to all gardens.

• Flowering time August to October
• Height at maturity 75 cm

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Solidago Strahlenkrone

A striking hybrid variety that has the advantage of being non-invasive. Also notable for earlier flowering. Essential in all gardens, even the smallest!

• Flowering time August to October
• Height at maturity 75 cm

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Solidago canadensis Gold King

A variety more compact than the species type. Suited to all gardens, in beds, borders or even in a pot on a terrace.

• Flowering time August to October
• Height at maturity 75 cm

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Solidago rugosa Fireworks

This goldenrod is distinguished by a very pretty compact, trailing habit and by its non-invasive character. Perfect for structuring a large bed of perennials or low bushes.

• Flowering time August to November
• Height at maturity 1 m

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Solidago rugosa

A botanical species that differs from horticultural varieties by a more airy habit and flowering in large pendulous sprays. Finds its place in all gardens.

• Flowering time September to November
• Height at maturity 90 cm

See the full description

Planting

Where to plant solidago?

Easy to grow and very hardy to at least -20 °C, goldenrod can be grown in all regions of France. It prefers full sun to flower well, however partial shade in southern regions is preferable. Give the tallest varieties, which can reach nearly 2 m in height, a spot sheltered from strong winds that could flatten the clumps.

Undemanding, this vigorous perennial will make do with any good garden soil, even tolerating poor or calcareous soil or occasional dryness. However, goldenrod will be more luxuriant in a cool soil, even slightly heavy or very clayey but well drained, slightly acidic. In dry ground its flowering may be less spectacular.

If recent varieties have a character that is noticeably less invasive than the botanical species, still make sure to give enough space because goldenrod tends to overshadow neighbouring plants.

An open site will encourage tall goldenrods to reach their full height.

The giant goldenrods are planted in groups in the middle or background of naturalistic beds, where they provide a vapoury relief and striking verticality. They are unmatched for structuring a large border of perennial plants or low bushes. Very graphic, they are perfect for composing rustic end-of-season scenes, full of liveliness, lightness and cheer in every corner of a natural garden, in a flowered meadow and even by the water or at the edge of a vegetable plot where they attract pollinating insects.

Dwarf or low goldenrods add interest to path edges, mixed-border and to a rockery that is not too dry.

When to plant?

Planting goldenrod is done in spring, from February to April, after frosts or in autumn, from September to November, after the hot weather.

How to plant?

In open ground

If Solidago will do in ordinary well-drained soil, it will flower more abundantly in cool soil. In poor soil it will cope but will likely be less floriferous: add well-rotted compost or potting compost at planting. You can plant Solidago singly, or in groups of three plants per m2 for a dense, striking effect: space plants 30 to 80 cm apart in all directions according to mature size. Staking is sometimes necessary for large specimens.

Allow plenty of space because some species of goldenrod are quite invasive and could colonise the ground to the point of preventing other nearby plants from growing.

• Dig a hole 2 to 3 times the volume of the bucket
• Spread a layer of gravel on the bottom of the planting hole
• Add a handful or two of compost to the garden soil
• Stake if necessary
• Water regularly after planting until established
• Mulch to keep the soil cool during summer

If you do not wish to stake: plant goldenrod with other tall perennial plants and bushes, which it can lean on to prevent its flower stems collapsing at the slightest gust of wind.

And follow our tips for successful planting of your perennial plants!

In a pot

• Plant your goldenrod in a large pot of at least 7.5 litres
• Spread a good drainage layer (gravel or clay balls)
• Plant in a mixture of garden soil and good potting compost
• Add a handful of compost
• Mulch and water very regularly: this is the guarantee of a good flowering

Caring for Solidago

Once well rooted, Solidago requires little care, becoming more luxuriant year after year.

In warm regions, mulch the base during summer to keep soil sufficiently cool throughout the warm season. Water regularly, but without waterlogging the soil. It will tolerate occasional drought, provided watering remains regular.

In a pot, water more frequently without ever allowing the substrate to dry out.

Taller clumps, very susceptible to wind, will need staking, especially in windy areas.

Inflorescence faded in autumn then frosted in winter

Rather fertile soil favours its development: fertilise each year at the start of spring, incorporating compost with a light surface fork-over.

Remove faded flowers regularly to encourage flowering and to prevent excessive self-seeding.

If you wish to harvest them: cut the tops just before the flowers open and dry these bunches suspended head down away from light.

In autumn or at the end of winter, clear dead foliage and cut the dried clump back to 50 cm above soil.

If you planted a vigorous-growing species of goldenrod in spring or autumn, divide clumps to restore vigour and contain their spread.

Diseases and potential pests

Easy to grow, Solidago is largely disease-free, except perhaps powdery mildew which leaves a white coating on leaves during drought or at end of season, when weather is warm and humid. Avoid excess water that favours development of fungus, water at base of plant avoiding foliage and follow our advice to limit appearance of powdery mildew.

Solidago foliage disappears in winter, reappearing in spring, when young shoots then become target of slugs and snails. Discover our 7 ways to tackle slugs effectively and naturally and how to make a slug trap.

Propagation: Clump division

If goldenrod has a natural tendency to self-seed or to spread on its own, it can also be easily propagated by dividing the clump in spring, on mature stumps at least 3 or 4 years old.

• Using a fork or spade, gently lift the clump
• Divide off a few offsets from the periphery of the rootball
• Replant immediately in fresh, enriched, well-drained soil

Companion planting with Solidago in the garden

A reliable choice for naturalistic gardens, goldenrod is unrivalled for lightening compositions and inspiring scenes with a wild, abundant look with effortless simplicity. Its sunny tones are welcome in late summer and early autumn.

While large goldenrods structure the back of naturalistic beds, their versatile nature also allows them to add movement to borders, mixed borders or to punctuate with their tall stature the flowering meadows.

Solidago is perfect for taking over flowering between summer-flowering perennials and autumn-flowering perennials.

Planted en masse rather than alone, giant goldenrod gives substance to a bed with its intense yellow chromatic presence, which pairs easily with complementary blue or purple-flowered species such as asters, salvias, hardy geraniums, Echinops, Perovskia or a penstemon.

For a scene in explosive tones, pair it with Echinacea, Oriental poppies, daisies, agastaches, Helianthus.

A naturalistic planting idea : Aster novae-angliae ‘Purple Dome’ (or ‘Violetta’ taller or a mix with ‘Little Carlow’), Solidago (altissima at back of bed or ‘Gold King’ or rugosa), Panicum virgatum ‘Shenandoah’, Helenium ‘Sahin’s Early Flowerer’ (and/or Helenium ‘Rubinzwerg’), Miscanthus sinensis ‘China’, and Monarda ‘Scorpion’… you can also add kniphofias, cannas…

Its loose habit will offer a shape contrast with plants equally high in colour but with more defined outlines such as dahlias, kniphofias, cannas, calmed by light grasses (Miscanthus).

In a bed dominated by yellow tones, its presence is essential alongside golden tansy, helenias, rudbeckias and achilleas, while grey or bluish foliage will temper the effect, such as artemisias, santolinas, stachys, hostas and blue fescues.

On the edge of the bed, smaller goldenrods will work wonders alongside coreopsis, small daylilies and leucanthemums.

A living mulch made of ground-cover perennials such as heucheras, periwinkles or bugle or of annual flowers such as nasturtiums and marigolds will keep freshness at its base.

To accompany summer’s last displays right up to winter’s threshold, the bright yellow of its spikes will resonate with perennial flowers in fiery hues such as Helenium, perennial chrysanthemums or autumn daisies and with annuals such as bidens, calendula or lantanas.

Goldenrods will enhance all warm tones planted at the feet of bushes with colourful autumn foliage such as deciduous spindle, purple oak, Parrotia or Cotinus.