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Australian Annuals

Many well known everlastings originate in Australia. Michael Forster looks at a range of Australian annuals including several new species just becoming available.

Australia's flora, extending to over 15,000 species, includes plants varying from the bizarre to many with great aesthetic appeal. Included in this latter group are many easily grown annuals only now beginning to receive recognition. Many are in the paper flowers or everlastings group, but other annuals are also very worthwhile.

After good rains the Australian outback is transformed into a sea of colour. In response, millions of annuals quickly grow and flower, carpeting the ground for as far as the eye can see. We cannot hope to recreate the same picture in our gardens, but we can certainly create massed displays in many delightful colours. Alternatively, we can use them, as with other more traditional annuals, to fill in vacant areas in established gardens. Some Australian annuals also make valuable container plants; massed in pots they can provide colour wherever desired.

Many of the everlastings are most attractive to butterflies and there is a further bonus with everlastings in that they are excellent in so many different ways for floral decoration. They can be used fresh or dried in arrangements or pressed and used to decorate gift cards.

Growing successfully

Probably the single most important factor in growing Australian plants successfully is an understanding of their past history and their adaptations, which have taken millions of years to perfect. These have been in response to three major influences, huge climatic variations from wet and cold to dry and hot, the extreme age of the soil, and the unique effect and frequency of fire.

Accordingly Australian plants have adapted to periods without water, poor soils deficient in nutrients and minerals and, in particular, soils low in phosphorus. The last probably underlies the incorrect generalisation 'Australian plants can't be fertilised'. Whilst caution should be used in application, Australian plants like any others require the essential growth elements and normally a general fertiliser such as N:P:K: 10:9:8 or thereabouts will prove quite safe.

Many plants in the bush are growing below their potential, but in our gardens we want to grow plants at their best with good foliage and maximum flowers, even more so with annuals. Therefore we have to ensure that essential growth nutrients are available. Like other annuals they will respond to the usual liquid fertilisers such as Phostrogen and Maxicrop and regular use is recommended although perhaps at half-strength. Organic manures, except poultry, can also be used to advantage.

The flowering period is mainly from late spring through to late autumn and plants can reach this stage in 8-12 weeks, often less, under favourable conditions.

Propagation

In general, Australian annuals should be treated in a similar manner to any of the commonly grown annuals. There is no special expertise needed, provided that watering in the early stages is not neglected. Plants can be successfully raised in seedling containers then transplanted to their selected positions, or seed can be sown direct into the garden area. The main requirement for seed sowing is a very well drained medium: 3 parts (by volume) coarse sand, 1 part sterilised loam, plus 1 part peatmoss is ideal.

Sow the seeds very thinly and barely cover with the seed raising mix or vermiculite. This assists in preventing any fungus attack and allows easy transplanting. It is then most important to maintain moisture levels until germination occurs, usually within 7-14 days. Some Australian plants are not easy to transplant but most annuals can be handled in the same way as other annuals. However, wherever possible, they should be pricked out early on, preferably at the first two-leaf stage.

When sowing directly out of doors select an open location receiving as much sunshine as possible. Ensure the topsoil is well cultivated and there is a well drained mixture of fine and coarse particles. Add some organic material to sandy soils, Gypsum and coarse sand to heavy clay types. Before sowing, roughly level the soil and broadcast the seed evenly but thinly. Either gently firm down or lightly cover with seed raising mix or sand.

Regular watering is a must for good germination but do not waterlog. Protect emerging seedlings from slugs and snails. Fertilise as described earlier and keep weed-free especially during the early stages.

Choosing Australian Annuals

Many Australian annuals are, as yet, little known and seed is hard to obtain. However, the following are very suitable for creating 'drifts' of colour to your own taste and providing an excellent source of cut flowers and are usually stocked by one or other of the major seed suppliers.

Ammobium alatum Winged everlasting

Hardy perennial (treat as half hardy annual) with silvery-grey leaves forming a clump. The 20in (50cm) flowering stems are strikingly winged and bear bright yellow flowers surrounded by white 2cm papery bracts in summer. S H F C.

Brachycome iberidifolia - Swan River Daisy

Occurs naturally: in the tablelands area of New South Wales. Grows to 12in (30cm) with finely-divided foliage and 2cm daisy-like flowers. Flower colour varies from white to blue and mauve. It is common in cultivation and readily available. A superb colour form 'Purple Splendour' is very worthwhile. S SS R.

ephalipterum drummondii Pompons

Occurs naturally: in Western Australia. A most attractive annual with 2cm globular heads of many papery flowers, in yellow or white. This species grows to 12-16in (30-40cm) and is a most attractive plant useful for spot colour. S SS C R.

Craspedia glauca Billy Buttons

Occurs naturally: in South Australia and Western Australia. Rosettes of light green often woolly leaves, below semi-globular flower heads varying in colour from pale yellow to orange on upright 12in (30cm) stems. Effective as single specimen or massed bedding. S H C R.

Craspedia globosa

Occurs naturally: in all States. A larger species, with flower stems up to 39in (1m). Heads of orange flowers may be 2-3cm in diameter. S H C.

Clianthus formosus - Sturts's Desert Pea

Occurs naturally: in inland areas from South Australia to Queensland. A spectacular trailing plant with silvery green foliage spreading in nature to 6Oft (2m). Produces brilliant scarlet red flowers with black eyes in clusters. The floral emblem of South Australia. Sturt's desert pea has been in cultivation for many years but is a challenge to grow. It does not like disturbance so seed must be sown in situ or in Fyba growpots.

Helichrysum bracteatum - Straw Flower

Occurs naturally: arid southern regions from N.S.W. to W.A. Very variable species, annual or perennial, some prostrate, others to 39in (1m) and more high. Usually 1-2in (3-5cm) yellow or white shiny petal-like bracts. This species is very variable and many unrecognised forms and varieties exist. Plant breeding work, particularly in Germany, over many years has produced some outstanding annual mixtures of purples, browns, oranges and reds, and with both dwarf and compact, and upright and tall habits e.g. 'Bright Bikini', 'Hot Bikini' etc. There is also a tetraploid mixture with spectacular blooms up to 3in (8cm) across. SSSHC.

Helichrysum subulifolium

Occurs naturally: in all States. This species has shining golden yellow, papery flower-heads up to 2in (5cm) across. Plants grow to 11 in (45cm) with smooth, narrow leaves. A new variety 'Golden Star' is particularly bright. S H C.

Helipterum humboldtianum

Occurs naturally: in Western Australia. Fragrant 3in (8cm) clustered heads of golden flowered everlastings. The plants have wavy-edged attractive silvery leaves and reach 18-24in (45-60cm). S H C.

Helipterum manglesii - Swan River everlasting

Occurs naturally: in Western Australia. This highly ornamental everlasting is well known in cultivation. A very floriferous, branching plant its deep pink flowers with yellow centres fading to create the effect of varying colours on one plant. The buds are pendant but open to erect flowers 1in (2.5cm) across. Improved strains, with larger flowers in rose, white and mixed, are now commercially available. It is very reliable and ideal for mass bedding, informal plantings and naturally cut flowers. Grows to 12in (30cm). For mass display space l0in (25cm) apart. Frost can damage young seedlings. S C R.

Helipterum roseum - Paper Daisy, Rose Sunray

Occurs naturally: in Western Australia. A most popular annual reaching 12in (30cm), quick growing and very showy. The papery flower heads range in colour from white to pink to almost red, with yellow or black centres, about 1½in (4cm) across. Delightful, double cultivars in separate colours are available from some seed suppliers. Ensure young seedlings are protected from heavy frosts. S SS C R.

Helipterum splendidum - Showy Sunray Splendid everlasting

Occurs naturally: in Western Australia. A sturdy annual growing to 2ft (60cm) with smooth, narrow leaves. Large 2in (5-6cm) paper-thin heads of single cream or white flowers with yellow centres. The large flowers make it attractive in small groupings. S SS C R.

Hibiscus trionum - Flower of the Hour

Occurs naturally: in Western Australia. A bushy annual growing 15-18in (38-45cm) with lobed leaves 3in (7cm) long. The large creamy yellow flowers up to 3in (7cm) diameter with brownish-red centres are produced freely in summer. Needs full sun and rich, well-composted soil. A good bedding, feature and container plant. Thompson & Morgan list an improved variety 'Sunny Day' with lemon blooms with purple-black centres which last all day and are continually replaced. S R.

Lawrencellia rosea Paper Daisy

Occurs naturally: in Northern Australia (also Asia and Africa). Another showy everlasting growing to l0in (25cm) with attractive foliage and literally covered in summer with bright pink (but can be variable) open flowers up to 1 inch (3cm) across. S H C R.

Podolepis gracilis Showy Daisy

Occurs naturally: in Western Australia. An attractive everlasting with soft basal leaves from which numerous wiry stems of attractive 13-25mm rose-pink blooms rise. 1-2ft (30-60cm). Ideal for edging, borders or informal groups. S C R.

Trachymene caerulea - Blue Lace Flower

Occurs naturally: in Western Australia. Rottnest Island daisy. Well known and excellent summer-flowering annual. Growing 18-24in (45-60cm). The terminal, pin cushion-like 2in (5cm) heads of light-blue flowers are freely produced on strong stems. Pinch out growing tips to encourage branching. S SS C R.

KEY TO SYMBOLS
S = Open sunny position
SS = Will take semi-shade
H = Frost hardy to 20F (-7C)
C = Useful as cut flower
F = Recommended for foliage
R = Especially suitable for rockeries, small groups, and container growing

Source of article
Growing From Seed - Autumn 1987 Vol. 1 Number 4
© The Seed Raising Journal from Thompson & Morgan