Summer annuals

Longing for an abundance of blooms in time for the festive season? Want to attract pollinators to your garden?  Summer flowers can be grown from seed, planted as seedlings or purchased as potted colour to instantly transform your garden.

Here are some of our favourite summer annuals. Check with hardware and garden centres for plants that suit your location and climate.

  • Alyssum (Lobularia maritima) Commonly known as sweet Alice, this ground hugging annual is one of the best plants to grow to attract bees, butterflies and beneficial insects. White, mauve and purple flowering forms are available. Sweet Alice is traditionally seen as a self-sowing annual, but modern plant breeding has changed all that. Look for the perennial variety, Lobularia Snow Princess which is propagated from cuttings. Lightly trim plants every 6-8 weeks for repeat growth flushes and new blooms.
  • Bedding begonia (Begonia semperflorens) Fleshy foliage and a neat rounded growth habit make begonias the ideal choice for formal gardens or pots. Flowers may be white, pink or red with contrasting foliage in green or brown tones. Plants grow up to 30cm high and have a similar spread. They are perennial in subtropical gardens.
  • Calibrachoa Commonly known as mini petunias, million bells or trailing petunias, these relative newcomers to the summer flower palette get better with every new release. Growing to just 20cm high they are prolific bloomers and come in just about every colour imaginable as well as double flowered and bicolour mixes. Grow them in pots in tropical and subtropical climates.
  • Celosia (Celosia species) Modern dwarf celosia blooms look like little Christmas trees, making them particularly popular features in pots and planter boxes over the festive season. But the range available also extends to the 50cm high Celosia Intense with its multiple heads of intense pink plumes through to the taller growing high Celosia ‘Dragon’s Breath’ with its red foliage with larger, deep-red, feathery blooms.
  • Coreopsis (Coreopsis species) This diverse range of daisy-flowered annuals and perennials grow from 30cm to 1m or more in height depending on the type you choose. Hardy and heat loving, they give a great cottage feel to any garden. Check with your local authority before planting as some species are roadside weeds in regions with warm winters. Fortunately, there are plenty of non-invasive varieties to choose from.
  • Cosmos (Cosmos species) Quick germinating cosmos are a popular inclusion in flower meadow plantings, but are also great for adding quick colour in gardens. Plants have a tendency to be tall growing and this makes them perfect for establishing in between existing shrubs where they will find support.
  • Globe amaranth (Gomphrena globosa) The globular-shaped combination of bracts and blooms of the globe amaranth dry naturally on the plant to provide colour and interest for months on end. White, pink and purple selections are available.
  • Marigolds (Tagetes erecta, T. patula) Dwarf French marigolds and the taller African marigolds are firm favourites for summer planting or for year-round colour in warm climates. To get the best out of your marigolds, remove the flower buds for the first 4 weeks after planting and prune spent flowers to encourage repeat blooming.
  • Petunia (Petunia species) The large trumpet-like blooms of fast-growing petunias provide great impact in pots, hanging baskets and gardens. They thrive all year round where winter temperatures are mild. Look for perennial petunias like Supertunia that grow 30cm high with a 1m spread.
  • Portulaca (Portulacca oleracea) Low growing and tolerant of root competition, portulaca is ideal for both garden planting and for providing colour at the base of established potted plants. Yellow, orange and pink blooms dominate the colour range in mixed seedlings packs. Mixed and single colours feature in potted colour. Look for new releases with increased bloom size and varieties with variegated foliage.
  • Salvia (Salvia species) Sun loving salvias are some of the hardiest and most heat tolerant flowers you can grow, but are also surprisingly well-adapted to part shade. Seed and seedlings tend to be smaller growing varieties, while those sold in pots are more likely to behave as larger growing perennial shrubs. Salvia is well-known for supporting active populations of bird and insect life.
  • Vinca (Catharanthus roseus) Also known as periwinkles, few summer flowers are more sun and drought tolerant. They are long lived in many regions and provide flower colour in the garden for extended periods. Cut plants back and fertilize when they are past their best and you will be rewarded with new growth and new flowers.
  • Zinnia (Z. angustifolia) The stately, tall growing zinnia (Zinnia elegans) is popular for garden planting and as a long- lasting cut flower. The dwarf growing star zinnia ( angustifolia) may be less well-known, but compliments both traditional flower gardens and those planted to native species. Both produce daisy blooms that attract a variety of insects.

Growing conditions

Climate There are summer annuals suitable for all climates. These heat lovers brighten and bring life to your garden from early summer through until autumn and beyond.  In regions with warm winter temperatures, they often grow all year round. They are perfect for pots, planter boxes and hanging baskets and will grow well in garden beds where soil depth is limited.

Soil Enrich the soil with home-made compost or fork in Seasol Super Compost prior to planting. Use Seasol Super Soil Wetter & Conditioner where the soil is water repellent. Seasol Advanced Potting Mix is perfect for summer flowers grown in pots and planter boxes.

Aspect Peak flowering is achieved in positions with full sun, but part-sun and afternoon shade are tolerated by many of our recommended favourites listed above.

Melbourne Begonia Society Show and Sales
Tips and advice on how to achieve a bumper annual flower display

General care

Watering Maximize seed germination by keeping the soil moist and gradually reducing watering as seedlings become more established. Potted flowers in full sun should be mulched, but may require daily watering during the peak of summer. Garden grown plants are likely to need watering at least twice a week. Seasol can be applied at any time to encourage strong root development, increase drought tolerance and boost disease resistance.

Feeding Rapid growth and repeat flowering require a lot of nutrient energy.  Add PowerFeed Controlled Release Flowers, Fruit & Citrus into the soil when planting and feed fortnightly with PowerFeed PRO SERIES Plant Food Roses & Flowers or PowerFeed All Purpose including Natives.

Pruning Modern plants are bred to be self-branching, while some others naturally have a clumping habit. However, most summer flowers also respond well to pinching, dead-heading or renewal pruning.

Watch for Young flower seedlings are prone to attack by snails and slugs, so keep them protected. Any leaf pests that occur on young seedlings can be controlled with Earthcare Natural Pyrethrum insect spray.