Summer-flowering bulbs

Summer-flowering bulbs, which include naked ladies (Amaryllis belladonna), liliums, tuberoses, gladioli, zephyranthes, crinums, and dahlias fill the garden with colour through summer with minimal effort. They can be planted on mass or individually in pots. Many continue to bloom into autumn where they are joined by sprekelias, nerines and autumn-flowering crocus. Check with your local hardware or garden centre for varieties that suit your local climatic conditions.

These bulbs are planted in spring when the bulbs are resting but can be planted as potted plants in flower in summer. Bulbs can be grown in garden beds or in containers and most re-flower year after year. Tall growers such as dahlias or liliums may need the support of stakes, so it’s ideal to put these in at planting.

Growing conditions

Aspect Bulbs need a sunny location with full sun for most of the day and protection from hot winds so flowers last longer. Some bulbs like blood and paintbrush lilies cope with good light rather than direct sun, while others like hippeastrum, naked ladies and nerines prefer full sun for at least six hours per day. If grown with too much shade they may fail to flower.

Soil and Planting Compost and nutrient-enriched, free-draining soil provides the best conditions for rapid growth, flowering and bulb multiplication. Add your own compost and/or Seasol Super Compost when preparing the soil and use Seasol Plant + Soil Booster when planting. Seasol Advanced Potting Mix is ideal for potted bulbs. Planting depths preferred by different bulbs are detailed on the rear of the packs.

Climate Summer and autumn-flowering bulbs are widely adaptable across a range of climates providing they have well-drained soil. Avoid planting frost-tender bulbs such as gladiolus, lilium and dahlia until after all threat of frost has passed. Gardeners in drier climates should increase watering for species that enjoy summer rainfall. Gardeners in climates with summer rainfall can grow bulbs that prefer dry summers by planting them in bed under the eaves of buildings or in pots. Bulbs are ideal for pots as it allows them to be moved as the season dictates including protecting sensitive types from frost.

General care

Watering Drought tolerance is a feature of many bulbs during dormancy, but once bulbs begin to shoot, regular watering is needed to support flower and foliage growth. Keep the soil moist, but take care not to overwater as this can cause bulbs to rot. Where the soil is water repellent apply Seasol Super Soil Wetter & Conditioner. Water with Seasol or Seasol GOLD regularly every two weeks to promote healthy growth, strong root development, drought and heat tolerance and pest and disease resistance.

Feeding and mulch Keep your bulbs growing and flowering strongly through the hottest periods of the year by applying PowerFeed with Troforte Flowers Fruit & Citrus six weeks after planting. Maximise stored food reserves in bulbs for bulb multiplication and more flowers the following season by watering with PowerFeed All Purpose including Natives or PowerFeed PRO SERIES Plant Food Roses & Flowers fortnightly from first signs of foliage through flowering until foliage has completely died back.

Spread mulch such as Lucerne, sugar cane or straw around bulbs to deter weed competition. Add well-rotted manure and Seasol Plant + Soil Booster to the mulch for extra nourishment and to improve the soil.

Pruning and dividing Remove dead foliage and spent flower stems to reduce seed formation, which take energy that would other be stored for next year’s growth, but avoid pruning the bulb foliage prematurely after flowering. While the foliage is still green, it is adding stored food and enhancing the flowering potential of the bulb in the following season. Leave foliage to die back naturally then tidy up taking care not pull up bulbs. Marking where bulbs are planted helps avoid digging them up when they are dormant.

Most summer and autumn flowering bulbs can be left in the ground year-round in frost free zones. In cool, frost prone regions plant and divide summer and autumn bulbs in winter or spring when the danger of frost is over. In warm climates plant and divide in autumn and winter. Division is best done every three years.

Diseases and pests Fungal and bacterial diseases can also affect plants grown in poorly drained soil or in climates subject to extended rainfall and high humidity. Clear away old foliage from the base of plants to improve air circulation, reduce fungal and bacterial rot. This will also limit shelter for slugs and snails. Use commercial iron-based products (safe for pets and other wildlife) to trap snails and slugs. Also watch out for earwigs which can damage flowers especially dahlias.

Crinum grubs or lily caterpillars (Spodoptera picta) are the larvae of large cream and brown moths. Eggs laid on the leaves develop into caterpillars that burrow into leaves, stems and bulbs, encouraging secondary infections of fungi and bacteria that cause bulbs to rot. Inspect plants regularly and remove eggs laid on the undersides of the leaves and young black and white striped caterpillars plus mature egg-laying yellow-striped adult grubs. Birds find the caterpillars unpalatable, so spray with Earthcare Natural Pyrethrum insect spray where large infestations occur.