Plant Solutions

Height and spread: 45–60cm × 20cm (18in–2ft × 8in)

Companion plants: All sweet Williams make excellent border plants, as they are at home with most perennials. Particularly effective with such flowery summer annuals as cornflowers, larkspurs, marigolds and poppies.

Callistephus hybrids

Bedding Asters Half hardy annual

Popular both as bedding or for cut flowers, these daisy relatives have showy ray florets in pink, purple, white, cream and wine red. Many different forms are widely available. Good cutting kinds, with long lasting qualities, include ‘Truffaunt’s Peony Mixed’, whose petals are incurved, and ‘Super Chinensis’, which has single flowers with bold, yellow centres.

Soil preference: Fertile, free-draining

Aspect: Sun or part shade

Season of interest: Summer

Height and spread: 30cm × 20cm (1ft × 8in)

Companion plants: If varieties are chosen with gentle colours, asters make great companion plants for red, pink or white bedded roses. Also fine in rows in a kitchen garden.

Molucella laevis

Bells of Ireland Half hardy annual

A member of the deadnettle family whose main features are the large, pale green, bell-shaped bracts which surround the tiny, off-white flowers, and which persist for the whole growing season. The foliage is unremarkable. Stems with the bracts are as effective when used dried as when they are fresh.

Soil preference: Fertile, free-draining

Aspect: Sun

Season of interest: Summer

Height and spread: 60cm × 25cm (2ft × 10in)

Companion plants: Normally grown for cutting though Molucella can look attractive among white flowers or with silvery foliage plants such as Artemisia ludoviciana or Salvia farinacea ‘Victoria’.

An informal grouping of Campanula lactiflora with a red flowered opium poppy.

Planting Schemes Using Annuals

The main point about annuals – and therein lies their charm – is that they are shortlived. Even the most stalwart, enduring individuals are done after a few months; few last for more than half a summer and many flower and die within a few weeks. Effective planting, therefore, depends on rotation, careful timing, large numbers and bold placing.

Many annuals are also somewhat unpredictable, growing larger and brighter than expected in favourable years, but failing to achieve their potential in difficult seasons. Since they seed copiously and since many adopt the role of biennials and will survive a winter, having germinated in the autumn, their short lives are often compensated for by rapid reproduction and a sustained succession. With the hardiest, such as Nigella, Calendula or Papaver, flowering can sometimes come in waves, with early and copious summer flushes from seed sown the previous autumn, a further wave from spring-germinated seed and a finale from summer-sown seed. Flowering times can also be brought forward by artificial sowing, pre-season, in trays or cells and planting out the young plants. Tender annuals will not sustain their colonies outdoors, where winter frost is expected, but hardy species can be left to their own devices and should ensure colour through much of the growing season.

Annuals as blenders

Although they work very well in their own company, the most common use of annuals is as gap fillers, or to accompany other, more permanent plants in mixed schemes. The main picture shows an informal grouping of Campanula lactiflora (bellflower) with red-flowered opium poppies. The foliage of both plants contrast well, the pale, glaucous leaves of the poppy having a markedly different colour, texture and shape from the smaller, rougher leaves of the bellflower. As they bloom, the large poppies are backed up by the starry, curled petals of the bells in their pastel lavender tones.

The photograph represents a tiny moment, probably no more than a 60th of a second! The plant association needs to last for several weeks at least and preferably for months, and yet each poppy blooms for no more than a day. The display, however, is far less ephemeral than it looks. After flowering, the campanula would be cut hard back to promote a second flush of flowers. As the opium poppy loses the last of its petals, the shapely seed capsules, held on stiffening stems, will continue to provide an architectural outline. By the time the bellflower has re-grown and is blooming again, the spent poppy will shift in colour from glaucous green to beige, and hence will continue to provide a contrast.

Caution is needed with the poppy, as with many annuals, to prevent unnecessary spread of seed by destroying seedlings while still young. Poppies, among all annuals, are probably the most fecund, and their seeds have a staggeringly long period of viability, countable in decades rather than years!

This group is spectacular for the present, but less successful as a lasting association. The candytuft (Iberis) makes a strong companion to the Korean perennial Campanula takesimana, picking up some of its tones but with cleaner, brighter colours and making a bright carpet. However, although it is slightly longer in flower than the poppy, it lacks an attractive aftermath and has undistinguished foliage.

Annuals for attracting beneficial insects

Clarkia pulchella

Hardy annual

A pretty annual from the Rocky Mountains with thin stems furnished with attractively ruched, funnel-shaped flowers in soft hues of pink, mauve or rosy purple. Gardenworthy seed series include ‘Choice Double Mixed’ and ‘Apple Blossom’, whose flowers, being apricot with white touches, could hardly look less like apple blossom!

Soil preference: Any free-draining, reasonably fertile

Aspect: Sun

Season of interest: Summer

Height and spread: 45cm × 30cm (18in × 12in)

Companion plants: Plants with an understated beauty, best placed with other pastel, crimson or purple annuals. Or use as gap fillers in a mixed or perennial border.

Euphorbia lathyrus

Caper Spurge Hardy annual

A member of the spurge family which produces an erect, single stem with leaves held opposite one another in pairs, forming an unusual cross pattern. The green flowers, despite resembling capers, are highly poisonous and attract many species of fly which, in turn, attract predators. If wounded, all parts of the plant exude a milky, irritant sap.

Soil preference: Any

Aspect: Any

Season of interest: Spring, summer

Height and spread: Up to 1.5m × 25cm (5ft × 10in)

Companion plants: Not a great beauty but effective as a foil for more colourful plants. Its erect stance makes a pleasing contrast with more pendulous shapes including arching grasses and phormiums.

Linaria maroccana

Morocco Toadflax Hardy annual

A pretty annual whose branching stems are furnished with simple, narrow leaves, which terminate with long-lasting spikes of small, spurred ‘snapdragon’ flowers. Colours are very variable in the wild species, with pink, yellow, dusky red, white or purple, each bloom usually having a deep yellow pollen guide. Garden varieties include ‘Fairy Bouquet’ in mixed colours, ‘Fantasy blue’ and ‘Northern Lights’, which has fragrant blooms.

Soil preference: Any free-draining

Aspect: Sun

Season of interest: Summer