One of my earliest memories of gardening as a young adult is myself crouched in front of the television on a Friday night taking earnest notes from an episode of In Your Garden with Allan Seale about growing summer annuals. This short weekly segment, which ran from 1968 to 1987, must have been one of the earliest gardening shows on TV. Allan Seale (1919-2001) was my first garden guru and a complete inspiration to me when I was a novice gardener. He was so kind, gentle and encouraging, and that episode led me to rush out to a nursery to buy some petunias, which gave me much joy.
I'm not sure what reminded me of that memory, but recently I found myself buying a few punnets of summer annuals, including Petunia for some terracotta bowls in a sunny spot, and reflecting that it has been such a long time since I had done so. As my gardening journey proceeded over the years, and I found myself fascinated with different gardening fads and plants, the more simple pleasures of growing these annuals was lost - I am sure I regarded them as rather 'vulgar' at a certain point, when I was completely in thrall to the idea of English garden plants. I recall that I was horrified when my dear old neighbour suggested petunias for my newly built terraced garden in 1994. They certainly didn't fit in with the 'vibe' I was looking for at the time, and I filled those garden beds with delicate, cold-climate perennials, which ultimately didn't thrive that well in my Sydney garden. As I have embraced the idea of growing plants that do actually flourish in this climate, those old-fashioned favourite summer annuals that everyone used to grow, have a new appeal to me, and they fit in well with my semitropical style of gardening, as in fact most of them hail from warm climates, such as Mexico, Vietnam, South America, Madagascar and Africa, like my other plants. They can give a burst of colour very quickly and can be varied from year to year.
Another summer annual I am trying again this year is the good old busy Lizzie (Impatiens walleriana, ht to 60 cm). I loved these humble plants in my early gardening years, especially for their tolerance of shaded areas, where they would often self-seed, forming large carpets of flowers, with their bright, jewel-like colours, including white, pinks, reds, orange, lilac and purple. A few years ago, these plants basically disappeared from our gardens (and from nurseries), due to a nasty disease called 'Impatiens downy mildew'. Anyway, this year, they are back in the nurseries, so I have taken a punt and planted out a few.
Another summer annual to grow in shade is Torenia fournieri (ht 20-30 cm), sometimes called the wishbone flower, a relative of the annual snapdragon (Antirrhinum majus), as can be seen in its flaring, tubular blooms, coloured lilac blue with deep purple lips and a yellow throat. It enjoys rich, moist soil in either part- or heavy shade. Another good choice for such a spot is the bedding (or wax) begonia (Begonia Semperflorens-cultorum Group, ht 20-30 cm), with a profusion of typical Begonia flowers, and rounded, glossy leaves that may be green or bronze, or variegated. The single or delightful double flowers come in hues of sheeny pinks, white or red. The neat, mounded plants bloom over a long period in the Sydney climate: from mid-spring until late autumn. They tolerate dryness, but do best in soil with plenty of organic matter dug in.
For sunny spots, consider marigolds (Tagetes species and cultivars) with their showy flowers held above spicy-smelling, ferny foliage. They love sun and good drainage, coping well with dry soil. African marigolds (derived from Tagetes erecta) grow tall (up to 50 cm or more) and have bold, double blooms in shades of yellow and orange. French marigolds (derived from Tagetes patula) are more compact (ht to 30 cm) and blooms can be single or double in hues of mahogany, bronze, gold and red as well as the traditional yellow and orange. There are some cute miniature-flowered marigold seeds and seedlings around these days, including ones with single blooms, generally derived from signet marigolds (Tagetes tenuifolia). Another daisy-like summer annual is Zinnia elegans, with a wide variety of flower colours (including the alluring lime-green 'Envy') and heights (ranging from 15 cm to 1 m!); they enjoy the same garden conditions as marigolds. They make excellent cut flowers, and the single sorts often will self-seed from year to year. Catharanthus roseus (ht 60 cm), sometimes known as the Madagascar periwinkle (or vinca), has simple, flat flowers usually white, purple or pink on a bushy plant; the blooms generally have a dark red 'eye'. They are usually seen in sunny spots in the garden, it is also able to be grown in part-shade in Sydney.
There are a few summer annuals that can appear in a Sydney garden each summer through self-seeding alone! Browallia americana (ht 30-60 cm) is an easy-to-grow bushy annual from tropical South America, which has a mass of starry blue flowers with a white centre in summer and autumn; sometimes even into winter. It flowers quite well in part-shade even though it is usually recommended for a sunny position; and it grows in most soils. It is rarely seen for sale: if you are able to obtain even a single seedling from the garden of someone who grows it, you will have it forever, as it self-seeds prodigiously! Amaranthus species also self-seeds vigorously in my garden. As it grows to more than a metre tall, I pull out 99% of the seedlings, leaving the remaining few to achieve their full potential, with their long, cascading burgundy flower tassels. Amaranthus grows best in full sun, as does Cleome hassleriana , another tall summer annual, with pink, white or purple whiskery blooms, which pops up unbidden each year.
All of these summer annuals benefit from regular feeding with a soluble plant food, and frequent deadheading will extend the period of bloom. Pinching out the growing tip early on helps promote bushier growth. Mulching around them once they are established can help retain moisture and reduce weeds. Watch out for caterpillars, slugs and snails! Some of these annuals are perennials in their subtropical or even tropical native habitats (including petunias, bedding Begonia, Impatiens, Amaranthus caudatus and Catharanthus roseus), so they flower for a very long period, often well into autumn. Some may carry on from season to season in warm Sydney gardens, but they are usually best in their first year and can look pretty miserable in winter. Because they are actually perennial plants, many can also be grown from year to year from cuttings; and can also be pruned back when they look a bit gangly towards mid- to late summer and given some extra fertiliser: they will rejuvenate well. I remember Allan saying this about petunias all those years ago!
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