Autumn in the Shade

Nigel Rowland, from Long Acre Plants in Somerset, with his selection of great plants to provide seasonal colour and interest in the shade in Autumn. - 23 August 2022

Autumn is not often a season in which people consider plants for shady borders, here are some interesting and some very beautiful plants with colour and flowers at their peak during Autumn which give the gardener a number of options. I consider Autumn to start on the 1^st of September and end on 30^th November, the meteorological dates.

Moisture is as always the great limitation to many plants in the Autumn woodland garden, particularly so this year.  A shady border on the north side of a wall or building can be surprisingly moist. We sell many of the plants mentioned in this short piece to London gardens as they are well suited to shady courtyards.

Some woodland plants have adapted to dry Summers by going dormant, emerging afresh once the rains of Autumn come. Good examples include Cyclamen hederifolium, in both pink and white, with plain, mottled, to fully silver leaves and Colchicums.

Cyclamen hederifolium album

Even ferns, such as the Welsh polypody - Polypodium cambricum with its huge range of forms and cultivars, will go dormant in Summer emerging again in late Summer.  Some such as Polypodium calirhiza 'Sarah Lyman' don't emerge until October.

Polypodium cambricum 'Conwy'

Dry shade suitable for planting is deciduous tree shade or to the edge of broad leaved evergreen tree shade.  Conifer shade or those trees which have an allelopathic effect on plants eg. Juglans (Walnut) and Taxus (Yew) are beyond the scope of this article.

As well as those mentioned above,  the white wood aster Aster divaricatus (syn. Eurybia divaricata), particularly the black wiry stemmed  ‘Beth Chatto'  and its close cousin, the more robust and slightly more spreading, Aster shreberi (syn. Eurybia shreberi) and Liriope muscari, particularly, ‘Big Blue’, are all very adaptable.

Many perennials if given a prune post flowering will flower again in the autumn. Good examples include  Geraniums including the shorter Geranium  macrorrhizum forms such as the pink ‘Pindus’ and the white ‘Mt Olympus White’ will have a second flush of flowers in the Autumn. These forms and the larger cultivars often have very good Autumn colour.

 Persicaria viginiana ‘Lance Corporal’  has dark red flowers over the dark green leaves which have a purple chevron.

The European mountain woodland Gentian - Gentiana asclepiadea in both white and blue  is a key woodland Autumn flowering plant.

Gentiana asclepiadea

Asia provides a huge number of late summer and Autumn flowering woodland plants.  The Summer monsoon affects a huge area from India to Japan. Shade tolerant plants grow and flower in the wild when the soil is moist from these summer rains.  The ginger family Roscoea, Zingiber and Cautleya but also  Tricyrtis, Kirengeshoma, Begonia,  Saxifraga and  Impatiens have several Autumn flowering hardy species within each genera. Many of these plants have a tropical look about them (though hardy)  which work well in "exotic gardens”.

Cautleya 'Crug Canary'

Roscoea purpurea are late flowering and have large flowers, with a number of flower colours from purple through scarlet to pure white. ‘Spice Island’ has dark brown foliage and  purple flowers. ‘Red Gurkha’ is shorter to 30cm and has scarlet flowers and red stems; 'Snow Goose' is pure white.

Roscoea purpurea 'Spice Island'

Tricyrtis are actually in the Lily family but with rhizomes rather than bulbs.  ‘Spotted Toad’ produces spotted leaves and pink spotted white flowers, ‘Samurai’ glossy green leaves bordered with cream with purple flushed and spotted white flowers. ‘Taipei Silk’ has blue or purple edged flowers.

Begonia emeiensis has stout rhizomes out of which emerge upright leaf petioles and medium sized coarse textured green leaves with pink flowers in Autumn, and is very hardy. Begonia grandis (evansiana) has a number of cultivars, all easy to grow,  very hardy and will take dry shade if established first. Examples include 'Alba' (pure white) and 'Red Undies' with pink flowers and deep red to the underside of the leaves. 'Heron’s Pirouette' is tall, stout and has loose open panicles of pink flowers. A recent article in the RHS The Plant Review (March 2022) by Dan Hinckley discusses the large number of hardy Begonia species he has seen in the wild and some recently collected, which offer exciting possibilities for long term garden perennials.

Begonia grandis 'Red Undies'

Impatiens omieana from China looks half hardy but will survive being frozen solid in a pot every year and reliably regrow again each spring,  producing yellow flowers in the Autumn. ‘Pink Nerves’ has dark maroon foliage and pink veins, ‘Ice Storm’ silver flushed leaves, the typical species is bright green with yellow veins. Like all herbaceous Impatiens they need moisture during the growing season.

Kirengeshoma is from Japan and Korea, related to Hydrangea and likes similar soil. Yellow shuttlecock like flowers over acer like leaves, up to 1.5m tall.

It is worth considering that some perennials and ferns have good Autumn colour which can be quite striking. Examples include Mukdenia rossii with acer like leaves and panicles of white flowers in Spring followed by scarlet flushed foliage in Autumn. Gillenia trifoliata a north American member of the rose family has white flowers in Summer but fires with yellow through to deep orange leaves after the first frosts of Autumn. Osmunda regalis, the royal or flowering fern, has bright golden fronds in mid to late Autumn.

Evergreen ferns such as Polystichum setiferum ‘Divisilobum’  or the tassel fern Polystichum polyblepharum and grasses such as the dry shade tolerant Anemanthele lessoniana AGM (Pheasant tail grass) can and do provide a structure to shade beds,  linking the last of the Autumn flowers to the Galanthus and Cyclamen coum of early spring the first of which with us will usually be in flower by Christmas.

Nigel Rowland is the owner of Long Acre Plants, based in Somerset, a mail order planstman's nursery specialising in plants for shade. 

Website: https://www.plantsforshade.co.uk/