Some flowers provide extra scent or nectar or other appeals to their pollinators to make up for their lack of gaudiness. A few have been bred for curiosity value.

Among roses, look for Green Ice' (a miniature), 'Green Tea' and 'Greensleeves'. None of them are exactly 'Irish green'- more like a green flower quickly dipped in bleach.

But Zinnia 'Envy' is a good strong green, and Callistemon pinifolius (the green form) is a wonderful green bottlebrush. There are also pale green varieties of carnation, gladiolus, daylilies, Nicotiana 'Lime Green', and orchids. And then there are some of my favourite perennials – hellebores, euphorbia, Alchemilla mollis, hops … some of these are actually insignificant flowers surrounded by showy green bracts but they still count as flowers. Then there are the Green Goddess arum lilies, though they may not be entirely appropriate for a saint's day. Nor are they especially green, just a few streaks among the white…

I did see a wild green wonga vine here for a few years, till it vanished, as if nature decided it wasn't worthwhile persisting with.

St Patrick is celebrated with shamrocks. A shamrock is definitely green, even if no one can agree on what a shamrock is. We do know it has three leaves, as according to tradition St Patrick, father of Irish Christianity, used a shamrock to explain the Trinity to the Irish. The word may come from the Gaelic word seamróg [ˈʃamˠɾˠoːɡ], meaning young or small clover, possibly white, possibly purple, or possibly red flowered clover. Oxalis (seamsóg or wood sorrel) is another, though less likely, contender. Pick a leaf of clover or sorrel for your button hole, and probably no one will argue with you. You might prefer the traditional toast of whisky, with a shamrock (of your preferred species) in the mug.

There's far more general agreement among Southern Hemisphere gardeners that St Patrick's Day is the perfect time to plant sweet peas. There is also general agreement among flower connoisseurs that sweet peas – old-fashioned highly scented ones, or the newer varieties that have bred the perfume back in – are the most perfect backyard flowers ever and almost impossible to find in a florists. You need to grow your own or have sweet pea growing friends to harvest a giant bunches to their perfume the house.

Every few years I have a flush of optimism and sweet pea envy and plant the seeds. They are either eaten by snails, carried off by ants or germinate then die in a drought, get mangled in a hail storm or grow gloriously and then are eaten when the wallabies break in. Wallabies love sweet peas as much as I do.

Sweet peas come as both miniature and climbers – the climbers give more blooms for less space, and are also less likely to 'lodge' or fall over, be eaten by snails or lost among the weeds. They range from pure white through pinks, reds, mauves, blue and combinations of the above, small flowers or large, plain or ruffled and with about six to ten flowers on each stem.

Experts will tell you that the most fragrant sweet peas are not the best sweet peas for cutting. Sweet pea lovers like myself argue that if they are not fragrant, there is no point gathering a great big glorious bunch of them.

Disciplined gardeners, i.e. not I, sow sweet pea seeds a centimetre deep in pots which can be kept out of snail and wallaby reach, and won't get swamped by weeds. Transplant them into the garden when the climbing beans die back and you have some trellis free.

(But not where the choko vine was, in case it grows back and smothers your sweet peas next spring.) A friend grows hers in the well fertilised tomato enclosure each year after the tomatoes are finished to protect them from bower birds as well as snails.

You can plant sweet pea seeds later than St Patrick's Day, but you will gets stronger, longer bearing plants if they put on a good growth spurt before winter's cold arrives.

Sweet pea seed, like parsnip seed, can have poor germination rates, especially if it's more than a year old – a consolation when mine doesn't germinate. The plants won't do much except sit there and photosynthesise over winter, then begin to bloom in spring and, if you continue to feed them, water them, mulch them, keep them twining on their trellis and possibly spray with a seaweed-based foliar spray, they may keep blooming even to mid-summer.

And I will envy you. But at least I can manage to grow a few leaves of clover for St Patrick's Day, especially after the rain.

This week I am.... talking, watching the premiere of Diary of a Wombat and doing more talking. But in the meantime the garden will be:

f. @jackiefrenchauthor

t. @jackie_french_

i. @jackie_french_