Golden rod, Solidago

Add a flash of yellow to your garden after other summer flowers have faded with golden rod, and attract plenty of butterflies while you're at it. Take care, though - some varieties are highly invasive.

Recommended varieties

In the US, wild species of golden rod have an enormous range of flowers. They spurt up on roadsides and woodland edges, flowering next to wild asters and vernonia.

New American varieties have revived interest in golden rod. Traditional invasive forms are an excellent choice for wild gardens, where they can be used to create spreading drifts alongside Michaelmas daisies or other large autumn-flowering asters, such as A. laevis .

Some types start flowering in July, but most don't get going until late August and carry on through September. In mild autumns, they may be still going strong in October.

S . 'Golden Wings': one of the big, old hybrids growing to 1.2m (4ft) and more, with a spread of 90cm (3ft). Makes an impressive, bushy clump with typical golden-yellow flower heads.
S . 'Crown of Rays': small, well-behaved and clump-forming, rarely growing above 60cm (2ft) with a spread of 45cm (18in). The elegant yellow flowers, set against pale green leaves, open through mid and late summer.
S . 'Goldenmosa' : just about the best golden rod, it's vigorous but not over the top. The flashy yellow flowers open through late summer and create a clump 75cm (2.5ft) high by about 45cm (18in) wide.

Cut flowers

S . 'Golden Shower': another well-behaved, popular, golden-yellow form making a similar-sized clump to S . 'Goldenmosa'.

Dwarf cultivars

There are several dwarf cultivars that suit most planting schemes:

S. 'Cloth of Gold': golden-yellow flowers and won't exceed 30cm (1ft) high.
S . 'Goldkind': an attractive soft yellow that grows to about 50cm (20in) high.
S. rugosa 'Fireworks': another popular choice, growing to around 1m (3.5ft), with fine heads of yellow flowers and a neat habit.

Growing tips

Site and soil preferences

Provide moderately fertile, free-draining soil with full sun or possibly very light shade.

Planting companions

Try golden rod with the elegant hybrid, X Solidaster luteus 'Lemore', which often flowers into October. Use golden rods in yellow and violet or yellow and blue late-summer and autumn colour schemes.

Avoid the mildew-prone Michaelmas daisies and focus on healthier alternatives, such as Aster cordifolius and its hybrid 'Little Carlow', which is smothered in blue flowers, or the pale blue A. novi-belgii 'Climax'.

Dwarf varieties of golden rod can be combined with compact asters, such as A. novae-angliae 'Purple Dome', at the front of a border.