Dig It – August Tips from the Secret Gardener

Small Tortoiseshell on Rudbeckia

You might struggle to find space in your garden for any more plants at this time of year but squeezing in a couple of containers with plants to provide late summer nectar is worthwhile.

On a recent visit to the garden centre my eye was drawn to a lovely display of Dahlias and Rudbeckias which was proving very popular with the butterflies. Both these plants would be a great addition to the garden at this stage of the year. In addition to being pretty now, they will continue to flower until the first frosts, providing nectar when there are fewer sources for butterflies – especially those stocking up before hibernation such as the Red Admiral, Peacock and Small Tortoiseshell.

Small Tortoiseshell on DahliaDahlias and Rudbeckias are suitable for fertile, moist but well-drained soil in full sun and can be grown in pots or borders. Dahlia tubers will need protection from frost.


Butterflies prefer Dahlia flowers where the centre is open and the nectar easily accessible, such as ‘single’ and ‘collarette’ types (which have collars of smaller petals around the central disk).

The Small Tortoiseshells flitting around chose to land on Dahlia ‘Mystic Dreamer’ in particular. This pretty, 40cm-high perennial has bronze-purple foliage with pale pink flowers from June to October. Regular deadheading will encourage continuous flowering.

 Other popular Dahlias include:

  • ‘Amazone’ (stunning, two-tone, pink and red flowers sitting on upright, tightly-packed stems)
  • ‘Fascination’ (dark pink flowers over dark bronze-purple foliage, growing to around 80cm tall)
  • ‘Bishop of Llandaff’ (1m-high plants with dark foliage and red flowers from July to November)

Angle Shades Phlogophora meticulosa moth caterpillars have been known to feed on Dahlias, along with a variety of other herbaceous plants. The adults occur throughout Britain and can be seen all year round.


Rudbeckias, also known as Coneflowers or Black-eyed Susan, are herbaceous perennials which have large, daisy-like, golden flower heads with conical black centres.

Rudbeckia fulgida var, sullivantii ‘Goldsturm’ will flower from now until October. Likewise the more compact, knee-high Rudbeckia ‘Little Goldstar’

Rudbeckia species are used as foodplants by the caterpillars of some moths including the Dot Moth Melanchra persicariae, whose adults are on the wing in July and August across England and Wales

These abundant flowers will bring some stunning colour into your garden to maintain a delightful, summer feeling well into autumn.

Happy Gardening!
The Secret Gardener

Images courtesy of Poundbury Garden Centre