Dianthus thrives in an east-facing or north-facing border.

Johannesburg - Would you like a garden filled with pretty pastels, bold colour combinations or flamboyant purples this summer? The warmth of spring has arrived and now is the time to plant up a garden filled with annuals.

Landscaping with annuals is like painting with colourful paint. There are so many different coloured annuals. If used boldly and creatively, you can make your garden look bigger or smaller.

If planted now, annuals will be a riot of colour by October.

There are two ways to plant annuals: sow seed, or plant established seedlings known as bedding plants. If you are looking for seedlings, try ageratum, aster, bedding begonia, bedding dahlia, browallia, celosia, cleome, cosmos, impatiens, lavatera, lobelia, marigold, nierembergia, torenia, verbena, vinca and zinnia.

Sowing seed is not difficult, but there are a few tips for success.

Start by digging over the soil until it is crumbly and without any lumps. Add compost and a general fertiliser and rake before sowing. Water the soil well the day before planting. Sow seed in geometric rows or scatter it for an informal natural appearance. The soil will need to be kept moist until germination occurs, and the plants watered in dry weather.

For hot spots

The low, spreading growth habit of sun-loving alyssum, mauve nierembergia, yellow and orange nasturtiums, and verbena and portulaca are ideal as edgings, in pots, on banks and between paving.

Zinnias are a popular choice for the summer garden because of their ability to withstand heat. They range in height from tall cactus-flowered varieties to dwarf Thumbelinas, in colours of pink, yellow, orange, red and purple. Celosias (cockscomb) offer a contrast in flower shape and texture to zinnias, with silky plumes of pink, gold, orange and red.

Waterwise vinca hybrids (Catharanthus roseus) have a branching growth habit and round-petalled flowers in white, pink, apricot, lilac and grape, often with contrasting centres. They would blend well with taller growing white, pink, green, red and purple funnel-shaped flowers of nicotiana.

If you want a splash of red you can’t beat Salvia splendens, but if this is too bright, these annual salvias also come in cream, pink, salmon and burgundy. Use them massed, as accent plants, and in containers. The annual clary sage (Salvia viridis) has upright spikes of white, pink or purple bracts.

Need height?

Plant a quick-growing annual climber on fences and over arches. Cathedral Bells (Cobaea scandens) is a vigorous climber and needs space to show off its unusual flowers. The bell-shaped blooms that give the climber its common name open apple-green then change to mauve and finally purple.

Tall sunflowers are useful quick-growing temporary screens, and add height in a border. These are easy-to-grow annuals, given well-drained soil and sunshine.

Cosmos can also be used as temporary screens and as “see-through” plants in a border, their silky white and pink petals held above lacy foliage. Baby’s breath (gypsophila) with dainty white flowers on wiry stems, and white lace flower are two more “see-through” annuals.

An elegant choice for the back of the border is cleome, known as the spider plant because of the shape of its narrow white and pink petals and long seedpods. The cup-shaped pink and white flowers of lavatera contrast well with the flowers of cleome. Attractive Salpiglossis sinuata grows 60cm tall with trumpet-shaped flowers of red, pink, purple and yellow and prominent veining on the petals.

Colourful containers

There are a variety of annuals in single or mixed colours that can be planted in pots. Grow ageratum, bedding dahlias, salvias, zinnias, marigolds and bush nasturtiums in sun, and bedding begonia, impatiens, mimulus and torenia in light shade.

Annuals are also ideal as pot “fillers”, but for this to work all plants need similar conditions of sun, soil and water. Lime-green coleus with blue torenia works well in light shade, as do ferns with white impatiens.

Try sun-loving combinations of ornamental grasses and gazanias, Carex “Frosty Curls” with dwarf orange marigolds, mauve angelonia with purple and white petunias and purple lobelia, Browallia “Jingle Bells” and ageratum with neon-pink vinca, bright pink petunias and red-purple verbena with silver-grey santolina, and lime-green nicotiana with pink mini petunias and nutmeg pelargonium.

Indigenous annuals

Many of the plants we grow in our gardens can trace their origins to the wild flowers of the veld. Diascias, nemesias and lobelias are three well-known indigenous annuals, all with dainty flowers for edging paths, for mass planting and for pots.

Arctotis venusta is a reliable summer flowerer with rounded bushes covered in large white flowers with mauve centres. Gazanias, with their free-flowering habit and daisy-like flowers of yellow, orange, bronze and pink, are excellent as groundcovers for sunny banks, rockeries and pots.

It’s well worth a visit to a botanical garden or indigenous nursery for seeds or plants of the wild foxglove (Ceratotheca triloba), an annual that grows 2m in height with foxglove-like flowers of white and pink with lavender markings. - Saturday Star