Late Spring & Summer bulbs
Planting times
The planting window for late Spring and Summer bulbs in Melbourne is longer than many people realise.
Peonies: June to end of August
Lilies: June to end of September
Hippeastrums: June to end of October
Dahlias: September (or after the last frost) to December
Herbaceous peonies
Herbaceous peonies can be tricky to grow in Melbourne, but with patience and the right care it is definitely possible. There is an old adage about peonies that helps explain why patience is required: the first year they sleep, the second year they creep, the third year they leap. In other words, don’t expect flowers for at least three years! The exception to this is the Coral range of herbaceous peonies, which are better suited to the warm Melbourne Winter. They have a limited colour range and are more expensive, but can bloom as early as their second year.
Peonies grow from a ‘root’ – a large piece of woody stem with two or more pink ‘eyes’ (growing points) on it. In terms of care, the following elements are critical:
Peonies need lime, and lots of it. Dig in up to a 20cm pot full of lime when planting in the garden or a couple of handfuls when planting into a 30cm pot.
It is important not to plant too deeply. The ‘eyes’ should be barely covered with only 1-2cm of soil. Any deeper and they will not bloom.
Peonies are hungry feeders and need plenty of fertiliser during their growing season.
Although they like a sunny position in the garden, peonies are cool climate plants that need a cold winter to induce flowering.
As we rarely get frost in Melbourne, topping them with a 4 litre ice-cream tub full of ice for a few weeks during Winter will help trick them into flowering.
Peonies hate being disturbed, so once planted, leave them be. If you move them you will have another 3 year wait for them to settle in and re-bloom!
Lillies
There are hundreds of different types of lily, including Asiatic, Oriental, Trumpet, Longiflorum and hybrid crosses of these. Regardless of the type, most of the commonly available lilies are planted and grown in the same way.
Lily bulbs can be planted from June right up until the end of September. As lilies are never entirely dormant, the bulbs may already be starting to shoot by the time you buy them, but this has no adverse effect on flower or bulb quality.
However, it is important that they do not dry out while remaining in their packaging. Plant lily bulbs pointed end up and about 15cm deep, in free draining soil or potting mix.
They are best grown in morning sun, as flowers can burn in very hot afternoon sun. Keep lightly moist, but not wet during their growing season, and feed with a good quality fertiliser like the Growbetter All Purpose Fertiliser.
When cutting blooms for the vase, or when deadheading, aim to leave two thirds of the stem on the bulb. Allow this to turn yellow and die down naturally at the end of the season before cutting off close to the base, as this will help return energy to the bulb for the following year’s flower production.
Hippeastrums
Despite their dramatic and exotic looking blooms, Hippeastrums are extremely easy to grow.
They are especially well suited to growing in pots, which can be started off in filtered light or morning sun in a frost-free spot outside then brought indoors at the time of flowering.
Hippeastrums grow from large bulbs which do best in a relatively small pot of 14-18cm diameter. It is important to plant them with the neck and shoulder of the bulb above soil level – only the middle and bottom of the bulb should be buried below soil level.
They require very little water, so use a free-draining potting mix and a pot with plenty of drainage holes. If growing in the ground, avoid planting in an area that receives irrigation, as the bulbs can survive mostly on natural rainfall alone and rarely need supplementary watering.
Flowering begins in early Summer, with the leaves emerging later. Leaves will die down in late Autumn as the bulb enters Winter dormancy, although in mild Winters it may remain evergreen.
Hippeastrums are rarely troubled by pests or diseases. The most common problem is a reddish-brown spotting or streaking on the leaves. This fungal infection is usually caused by overhead watering, and can be prevented by watering only around the outer edge of the pot, avoiding the foliage and neck of the bulb. A fungicide such as Mancozeb may help if treatment is necessary.
Dahlias
Dahlias have become very fashionable again in recent years and it’s easy to see why. They are one of the easiest bulbs (tubers) to grow, producing an abundance of flowers over many months with very little care required. They grow well in large (30-40cm) pots, as well as in the ground.
Dahlias are frost tender so should only be planted after all risk of frost has passed. In Melbourne this is unlikely to be an issue, and Dahlias can be planted from September onwards.
Plant tubers horizontally about 10cm deep, with the ‘eyes’ (shoots emerging from the small piece of old stalk) slightly higher than the tail. As most dahlias are tall growing and benefit from staking, the stakes should be inserted at the time of planting – if you stake later, there is a high risk of damaging the tubers.
There is some debate as to whether or not it is necessary to ‘pinch out’ growing tips back to 3 or 4 pairs of leaves as dahlias start to shoot. Whilst this does produce shorter, bushier plants, it is entirely optional.
After planting, and throughout the growing season, keep your dahlias lightly moist, fed and deadheaded to prolong flowering.
Keep an eye out for slugs and snails as shoots emerge, and later for caterpillars which eat both the foliage and the flowers.
Hot and humid weather during late Summer can cause powdery mildew (a fungal infection). To help minimise this, avoid wetting the foliage when watering, and treat with a fungicide such as Eco Fungus or Fungus Gun.
Dahlias will usually bloom well into Autumn and right up until the first frost. Allow the stems to die down naturally before cutting down close to the base.
In frost free areas such as Melbourne it is not necessary to lift and store dahlias so they can remain in their pots or in the ground throughout their Winter dormancy.
