<em>Solidago</em>, goldenrod: planting, cultivation, 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, particularly Canada, and to eastern and central United States where it grows in a wide range of habitats, from mountainous areas and dry woods to fresh meadows, sandy fields, fallow land and riverbanks.

Genus comprises about 125 species including Solidago canadensis, or Canadian solidago, Solidago rugosa, Solidago gigantea or giant goldenrod. Many botanical species, now regarded as invasive, are increasingly abandoned (and in some cases banned from sale) in favour of non-invasive hybrid varieties, such as Solidago ‘Goldenmosa’, ‘Crown of Rays’ (syn. ‘Strahlenkrone’) or species with much less invasive habit, such as Solidago shortii or Solidago altissima, a tall goldenrod. Solidago virgaurea is widely used for its medicinal virtues.

From a more or less running rhizomatous stump, Goldenrod forms a dense erect 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 that makes them suitable for all gardens. They will need about two years to fill out and reach their full potential.

Solidago vigaurea – botanical illustration

On villous, erect stems, sometimes arching and ramified in upper parts, a deciduous foliage unfolds. Leaves lanceolate to linear, with dentate margins, are arranged alternately along stems. Colour ranges from bright green to chartreuse with a glossy upper surface; they are pubescent underneath and rough to the touch. Some species have stems of a reddish‑purple hue.

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 the ends of the flexible stems. These highly branched spikes are compact or pyramid‑shaped depending on species. All bear tiny mossy heads 5 to 8 mm wide resembling miniature daisies or mimosa, formed of five pedunculate lobes bending together in same direction. They explode in sprays, often gracefully trailing, in shades from pale yellow and bright lemon yellow to golden yellow, hence vernacular name “Goldenrod”!

Although unscented, this generous flowering rich in pollen and nectar is particularly melliferous, attracting pollinating insects well into winter.

Radiant inflorescences of goldenrods make airy, rustic summer and autumn bouquets. They can also be dried for use in dried arrangements.

These pollinated flowers give way to tiny winged fruits containing very numerous fine seeds ready to be dispersed by wind and self‑sow 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. Taller goldenrods such as Solidago altissima are planted at back of border, paired with other vigorous perennials or on pond edges. Dwarf species like Solidago canadensis ‘Gold King’ are reserved for path or border edges.

Solidago or Goldenrod is also used for centuries in herbal medicine for its medicinal virtues, notably to treat colds, lung and kidney conditions. Used externally, goldenrod promotes wound healing, hence its Latin name meaning “to strengthen”.

Goldenrod is an edible plant; its flowers, stems and leaves have a honeyed flavour and are consumed dried as infusions and herbal teas.

Main species and varieties

Most popular

Our favourites

Solidago Goldenmosa

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

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

See the product sheet

Solidago Strahlenkrone

A striking hybrid variety with 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

See the product sheet

Solidago canadensis Gold King

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

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

See the product sheet

Solidago rugosa Fireworks

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

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

See the product sheet

Solidago rugosa

Botanical species that differs from horticultural varieties by a more airy habit and flowering in large, weeping sprays. Suits all gardens.

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

See the product sheet

Planting

Where to plant Solidago?

Easy to grow and very hardy to at least -20°C, Goldenrod can be cultivated in all regions of France. It prefers full sun to flower well, however partial shade in southern regions will suit it better. Reserve a sheltered spot away from strong winds for the tallest varieties, which can reach nearly 2 m and may otherwise flop.

Not demanding, this vigorous perennial will be content with any good garden soil, even tolerating poor, calcareous or occasionally dry soil. However, Goldenrod will be lusher in a cool, even slightly heavy or very clayey but well-drained soil, slightly acidic. In dry ground, flowering may be less spectacular.

Although recent varieties are noticeably less invasive than botanical species, give it enough space because goldenrod tends to overshadow neighbouring plants.

A well-exposed position will encourage tall goldenrods to reach their full height.

The giant goldenrods are best planted in groups in middle or background of naturalistic beds, where they provide a vapoury relief and striking verticality. They are incomparable for structuring a large bed of perennials or low bushes. Very graphic, they are perfect for composing late-season country-style scenes, full of vigour, lightness and cheer in every corner of a natural garden, meadow and even by water margins or beside a vegetable plot where they attract pollinating insects.

Dwarf or low goldenrods add vitality to path edges, mixed borders 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 high temperatures.

How to plant?

In open ground

Although Solidago tolerates ordinary well-drained soil, it will flower more abundantly in cool soil. In poor soil it will cope but will probably be less floriferous: add well-rotted compost or potting soil at planting. Solidago can be planted 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 size at maturity. Staking is sometimes essential for large specimens.

Give them space because some goldenrod species are quite invasive and could colonise the ground, preventing other nearby plants from growing.

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

If you prefer not to stake: place goldenrod among other tall perennials and bushes so it can lean on them and prevent flower stems from collapsing at first gust of wind.

And follow our advice to succeed in planting your perennial plants!

In a pot

• Place goldenrod in a large pot of at least 7.5 litres
• Lay a good drainage layer (gravel or clay balls)
• Plant in a mix of garden soil and good potting soil
• Add a handful of compost
• Mulch and water very regularly: guarantee of good flowering

Caring for Solidago

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

In warm regions, mulch the base during summer to keep soil cool enough throughout the growing season. Water regularly, but avoid waterlogging the soil. It will tolerate occasional drought provided watering remains regular.

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

Tallest clumps, very sensitive to wind, will need staking, especially in windy areas.

Inflorescence faded in autumn then frosted in winter

Rather fertile soil favours its development: fertilise every year at the start of spring, adding compost by light superficial fork-over.

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

If you wish to harvest them: pick the tops just before the flowers open and dry these bouquets hanging upside down away from light.

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

If you planted a vigorous species of goldenrod in spring or autumn, divide the 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 powdery coating on the leaves during drought or late in the season, when weather is warm and humid. Avoid excess water which favours the fungus; water at the base of the plant, avoiding foliage, and follow our advice to limit the onset of powdery mildew.

Solidago’s foliage dies back in winter and reappears in spring, when young shoots become the target of slugs and snails. Discover our 7 ways to fight slugs effectively and naturally and how to make a slug trap.

Propagation: Dividing clumps

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

• Using a garden fork, lift the clump gently
• Divide off a few offsets from the edge of the clump
• Replant immediately in well-drained, fertile, fresh soil

Pairing Solidago in the garden

A reliable choice for naturalistic gardens, Goldenrod is unrivalled for lightening compositions and inspiring simple, lush, wild-looking scenes. Its sunny tones are welcome in late summer and early autumn.

If tall goldenrods anchor the back of naturalistic borders, their versatile nature also allows them to add movement to edgings, mixed borders or to punctuate flowering meadows with their tall stature.

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

Planted in groups rather than singly, giant goldenrod gives structure to a border with its intense yellow presence that pairs easily with complementary blue or purple flowers of Asters, Sages, hardy geraniums, Echinops, Perovskia or a Penstemon.

For a scene of explosive tones, pair it with Echinacea, Oriental poppies, daisies, Agastaches, Helianthus.

A naturalistic pairing idea: Aster novae-angliae ‘Purple Dome’ (or ‘Violetta’ shown higher up or a mix with ‘Little Carlow’), Solidago (altissima as backdrop to the border 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 relaxed habit will provide a contrast of shape with plants equally vivid in colour but with sharper outlines such as dahlias, kniphofias, cannas, softened by light grasses (Miscanthus).

In a border dominated by yellow tones, it holds its own alongside golden tansy, Heleniums, Rudbeckias and Achilleas, tempered by grey or blue foliage such as Artemisia, Santolina, Stachys, Hostas and blue fescues.

On border edges, smaller goldenrods perform wonderfully alongside coreopsis, small daylilies and Leucanthemums.

A living mulch made of ground-cover perennials such as Heucheras, periwinkles or Bugles, or of annual flowers such as nasturtiums and marigolds will help retain freshness at its feet.

To accompany summer’s last blaze through to onset of winter, bright yellow of its spikes will be echoed by perennial flowers with flamboyant tones such as Helenium, perennial chrysanthemums or autumn daisies, and annuals such as Bidens, Calendula or Lantana.

Goldenrods will set off all warm tones planted beneath shrubs with colourful autumn foliage such as deciduous Euonymus, purple oak, Parrotia persica or Cotinus.