Nigel Colborn - Plant Solutions

Soil preference:Dry, not too fertile

Aspect:Sun

Season of interest:Summer

Height and spread:30cm × 30cm (1ft × 1ft)

Companion plants:The orange form makes a stirring companion to such bronze-tinted grasses as Stipa tenuissima or the sedge Carex buchananii . Also good in a gravel garden, where its misty foliage and silky petals will soften hard textures.

Geranium robertianum

Herb Robert Annual

An invasive annual with spreading habit, pungentsmelling, ferny foliage and a long run of tiny, pink, five-petalled flowers. The albino form, ‘Album’, is more distinctive. A thug in the wrong place, but charming when allowed to self-sow in drifts in gravel or along the edges of a path.

Soil preference:Any free-draining

Aspect:Sun or part shade

Season of interest:Spring, summer, autumn

Height and spread:20cm × 40cm (8in × 1ft 4in)

Companion plants:Naturalize this one with other gravel or paving crack plants such as Viola riviniana or Alchemilla.

Annuals for very rich soil

Consolida ajacis

Larkspur Annual

Classic cornfield annual which has been bred to improve height, standing power, and colour range. The leaves are finely divided and the tall, straight stems are furnished with spurred flowers in shades of pink or blue or white. Easy to raise from seed sown in autumn or spring, directly where they are expected to flower.

Soil preference:Fertile, well-drained

Aspect:Sun

Season of interest:Summer

Height and spread:Up to 1m × 30cm (3ft 4in × 1 ft)

Companion plants:Good as a cut flower and therefore effective grown among vegetables in a kitchen garden or in a mixed border. Attractive with roses, where the straight spikes make a strong contrast and where the blues and pinks of the flowers harmonize.

Helianthus annuus

Sunflower – large varieties Annual

Biggest of the hardy annuals and raised as food crops in Central America since prehistoric times. The stout stems are strong enough to carry the massive flowers and seed heads without support. Some ornamental varieties are sterile and bear no pollen. Field crop sunflowers are golden yellow, but cultivated forms include such colourful series as ‘Ring of Fire’, whose flowers have concentric ring patterns in hues of dusky red and yellow, or ‘Moonshadow’, whose flowers are cream.

Soil preference:Rich, fertile

Aspect:Sun

Season of interest:Summer

Height and spread:Up to 3m × 1m (10ft by 3ft)

Companion plants:Useful plant to create a temporary screen, or to use as accent plants in a bedding scheme, cottage border or kitchen garden.

Linum grandiflorum

Flowering Flax Annual

Slender, almost wiry stems with narrow, pointed leaves bear a long succession of disc-shape flowers up to 4cm (1¾in) across. In the wild, these are rosy purple, but seed selections include ‘Bright Eyes’, whose flowers are white with conspicuous wine red centres, and ‘Rubrum’, whose petals are a deeper rose with dark crimson centres.

Soil preference:Any, free-draining

Aspect:Sun

Season of interest:Summer

Height and spread:45cm × 30cm (1ft 6in × 1ft)

Companion plants:The waving stems and frail flowers look delightful among coloured grasses or sedges such as Carex comans or Molinia caerulea . Also lovely when naturalized among low-growing shrubs in a Mediterranean-style planting scheme.

Annuals for gap-filling in mixed borders

Cynoglossum amabile

Chinese Forget-me-not Annual

J. Swithinbank

Narrow, pointed leaves on branched stems are joined in early and mid-summer by clusters of small forget-me-not flowers in an intense blue. Pink and white flowered varieties are also available. The seeds are large and exceptionally hard.

Soil preference:Fertile, free-draining

Aspect:Sun or part shade

Season of interest:Summer

Height and spread:50cm × 30cm (20in × 12in)

Companion plants:Blue forms contrast sharply with the yellows of verbascums or, from later sowings, goldenrods and yellow daisies such as rudbeckias and heleniums. The intense blue would also relieve the monotony of a cool, silvery or white theme.

Datura inoxia

Downy Thorn Apple Annual

A large, much branched, characterful annual with big, oval leaves which are downy and slightly tacky to the touch. The huge trumpet flowers – 15cm (6in) or more long – are purple tinged when in bud, but open to a soft white. In the evening and at night they are heavily scented.

Soil preference:Any fertile soil

Aspect:Sun

Season of interest:Summer, autumn

Height and spread:Up to 1m × 1m (3ft 3in × 3ft 3in)

Companion plants:One to grow on its own, but for a heady cocktail of night fragrance, plant with fragrant tobacco Nicotiana affinis and the vanilla scented heliotrope.

Malope trifida

Annual Mallow Annual

Similar to annual Lavetera trimestris , but slightly smaller with more downy, heart-shaped leaves that hang down as the plant matures. Big saucer shaped flowers appear in succession throughout summer and colours in the various seed selections range from dusky and rose pink to bright magenta, deep plum and white.

Soil preference:Fertile but well-drained

Aspect:Sun

Season of interest:Summer

Height and spread:50–75cm × 45cm (1ft 8in–2ft 6in by 1ft 6in)

Companion plants:Better than lavatera for mixing with other such hardy annuals as cornflowers, clarkia, larkspurs, Convolvulus tricolor and corn cockle.

Zinnia elegans

Annual

The species has been used to develop a colourful range of tender annuals, with simple leaves, slightly rough to the touch, and flowers with attractive layered florets, often with dark ochre or yellowish fertile centres. Flower colours include white, yellow, pink, mauve, orange, red, maroon and even pale green with a variety of flower forms from single to pompon.