Quietly writing at my desk recently, I nearly jumped out of my skin at what sounded like a gunshot right under my nose. It was rapidly followed by another and then a third. To my total disbelief I saw some sweet pea seed pods, saved from last December and lying in a little dish on the blotter, were busily exploding and shooting out tiny bullet-like seeds in every direction.
I had no idea sweet peas (Lathyrus odoratus) behaved in this exciting way but it was a handy reminder of the approach of St Patrick’s Day, March 17, the traditional date for the annual sowing of the sweet peas. I’m forever amazed that this ancient gardening tradition, brought from the Northern Hemisphere, should have survived intact down to the actual date. You’d expect it to have moved to our spring, but not a bit, gardeners down under continue faithfully to sow sweet peas on March 17.
As it happens this is a good idea, as autumn sowing means plants flower earlier, in late spring rather than early summer. Sweet peas like a cool environment, so your flowers should last for several weeks before they’re knocked out by a heatwave. Tablelands gardeners whose summer arrives later may prefer to wait till September as early heatwaves are less likely to bother you.
If you want to get ahead and sow in autumn, find a sunny, sheltered corner and if necessary protect your seedlings from lurking frost with a layer of horticultural fleece. Sweet peas prefer alkaline over acid soil, so you may need to add lime – aim for a soil pH of around 6 (7 is neutral). They love lots of sun but their roots must stay damp, so mulch thickly and keep them well watered, especially when they start flowering. Most varieties are climbers so strong support is another important requirement. Weldmesh bolted to corrugated iron is effective, or wooden lattice on fibro. Ours grow on a south-east facing garage wall and the sun on the iron doesn’t worry them. I sow dwarf varieties at the front of the bed for ground cover. Sweet peas are blissfully easy to raise yourself, indeed they head the list of top five flowers to grow from seed in Yates Garden Guide. Spread seeds on damp paper until they sprout, then sow in individual plugs – a cut-up egg carton is fine – and plant out when seedlings reach ten centimetres. Pinch out the tips to encourage side shoots. If your life doesn’t allow time for annuals there is a perennial sweet pea, Lathyrus latifolia, but it comes in a limited colour range and has little scent.
Heads Up: Sweet pea seeds are in garden centres now. For mail order, Diggers Club (www.diggers.com.au/) and David Glenn’s Lambley Nursery (www.lambley.com.au/).
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