Companion plants: Like all pansies and violas, these plants fit anywhere with anything. Lovely in a cottage border, seeding among pinks, antirrhinums or in semi-shade with small dicentras or between polyanthus.
Matthiola incana
Stock, Brompton Stock Biennial
Glaucous, slightly downy, grey-green foliage which produces multiple short stems, or long single stems bearing highly fragrant single or double blooms in white or shades of violet, mauve or pink. Cutting varieties include Ten Week stocks, but the wild species is attractive for cottage garden use. Excellent bee plant.
Soil preference: Any free-draining
Aspect: Sun
Season of interest: Summer.
Height and spread: Variable to 1m × 20cm (Variable to 3ft 3in × 10in)
Companion plants: Once popular for overwintered bedding, Brompton Stocks are more frequently used to dot among early summer mixed borders, preludes to pinks or border carnations, or to grow among bush roses.
Biennials with distinctive foliage
Onopordon nervosum
Scottish Thistle Hardy biennial
R. Coates
Metallic, silvery-grey leaves form dramatic rosettes in autumn and thick, winged, branched stems rear up during spring and summer, creating tree-like structures decorated in summer with purplish red thistle flowers. Viciously armed in all its parts. A prolific self-seeder.
Soil preference: Any free-draining
Aspect: Full sun
Season of interest: All year, mainly summer
Height and spread: Up to 3m × 1.5m (10ft 9in × 4ft 6in)
Companion plants: Their architectural shape make these ideal plants for providing dramatic summer statements, particularly among soft outline perennials such as cranesbills. Also excellent in sparse gravel planting.
Lychnis coronaria
Rose Campion Hardy biennial
Loose rosettes of oval, felty, grey leaves develop in the first year. Branched, erect stems develop during the second spring and in summer carry a long succession of bright cerise, disc-shaped flowers. The form ‘Alba’ has white flowers which age to pale pink, whereas the petals of ‘Atrosanguinea’ are blood red.
Soil preference: Well-drained
Aspect: Sun
Season of interest: Summer
Height and spread: 1m × 50cm (3ft 3in × 1ft 8in)
Companion plants: A free self-seeder, which is lovely dotted about among the more rigid spikes of lupins or to harmonize with lavenders and Perovskia.
Silybum marianum
Our Lady’s Milk Thistle, Blessed Thistle Hardy biennial
Heather Angel
Dark green, undulating, prickly leaves, each marbled with white streaks, form a loose-knit groundcover during spring. Flower spikes develop in summer producing deep purple thistle flowers, but the value is in the foliage. The name arises from the legend that the Blessed Virgin Mary dripped milk onto the leaves. Watch for slugs and snails.
Soil preference: Any well-drained
Aspect: Sun or part shade
Season of interest: Summer
Height and spread: 50cm × 1m (1ft 8in by 3ft 3in)
Companion plants: Valuable for linking spring with summer and lovely among early flowering perennials such as lupins, early poppies and perennial wallflowers.
Other good biennials
Trifolium rubens
Hardy biennial
Heather Angel
A compact, bushy clover with typical three-lobed leaves and, during summer, elongated, slightly furry buds which open to produce tight groups of crimson flowers. An excellent cut flower and extremely bee-friendly. Like all legumes, the plant fixes its own nitrogen from the atmosphere.
Soil preference: Any free-draining
Aspect: Sun or part shade
Season of interest: Summer
Height and spread: 45cm × 20cm (18in × 8in)
Companion plants: A plant to blend harmoniously with the annual hare’s foot grass, Lagurus ovatus, whose flowers are similar in shape, but contrast in colour. Also good in a mixed border, to fill gaps between later flowering perennials.
Trifolium incarnatum
Italian Clover, Crimson Clover Annual or biennial plant
A vigorous annual or biennial whose young foliage is vivid emerald green. The three-lobed leaves form a neat mound during autumn followed, in late spring, by a succession of waving stems topped with oblong clover flowers in bright claret red. Not suitable for autumn sowing where winters are hard.
Soil preference: Any free-draining
Aspect: Sun
Season of interest: Summer
Height and spread: 60cm × 30cm (2ft × 1ft)
Companion plants: Valuable as a green manure, to be dug in before seeds are set, but also highly decorative among annuals or dotted among sun-loving Mediterranean shrubs such as Cistus, Artemisia and Helichrysum.
Dianthus chinensis
Hardy biennial
Fast-maturing species which has given rise to many garden series. The simple, narrow green leaves are all but hidden by the crop of brightly coloured flowers with pinked or serrated petals. Fine forms include the maroon and white ‘Black and White Minstrels’, brilliant red or white ‘Magic Charms’ and the pink or red ‘Victoriana’ series.
Soil preference: Any free-draining
Aspect: Sun
Season of interest: Summer
Height and spread: 30cm (1ft), variable by 20cm (8in)
Companion plants: Superb container plants, to blend with other summer flowers such as Lobelia erinus or with the foliage of Plectranthus and Glechoma hederacea ‘Variegata.’
Angelica