By: Justin Russell | May 7, 2015
At this time of the year contrast is the name of the game. There’s the tracery of bare branches set against blue skies. The contrast between cold mornings and warm days. And most significantly for garden advice columns, the contrast between Australia's diverse set of climate zones.
In the south, winter dormancy is beginning to take hold, reducing the flow of sap through many plants to little more than a trickle. It’s snowing on Tasmania’s Mt Wellington as I write, so have no doubt, the season of rest and renewal is pretty much here for you southerners. Throughout inland areas, frosty nights usually give way to sunny days, allowing for moderate growth. It’s a great season for pottering, punctuated of course with moments to sip warm drinks in glorious sunshine.
Along the east coast, winter crops tend to grow beautifully, but watch out for rabid east coast lows. The BOM says there’s a higher than usual likelihood this year. In the north, you’re basically doing the opposite of everyone in the south. Good for you. Get stuck into prepping and planting for the busiest gardening season of the year.
Start by considering plant health. Anthracnose is a major disease of fruiting trees in the tropics and subtropics. It manifests in the warmer months on plants such as avocados and mangoes, but control starts now. Apply potash around the root zone of trees to help thicken cell walls in the leaves, toughening them up and making them more resistant to the disease.
In the subtropics, the foliage of ginger is dying back, marking the start of the harvest season. Small clumps can be dug in their entirety. Break the tubers into large chunks, store some in a dark, dry place indoors, and replant the best into soil that you’ve enriched with compost or rotted manure. The same can be done with ginger relatives such as galangal and turmeric.
In cool areas, asparagus fronds are changing colour from green to yellow. The foliage has done its job collecting solar energy for the roots, and the changing colour is your cue to cut the plants back to ground level. With the foliage cut back, it’s an opportune time to apply a top dressing of spent mushroom compost, and a fresh layer of mulch. Take care not to bury the plant crowns.
The worst weed of winter in my garden is chickweed. Even though it’s highly nutritious for people and chooks, it’s a pain in the you know what. It pops up in the thousands, especially in my vegie patch, competing with vegies for space and nutrients. The seed germinates prolifically this month in warm temperate areas, so get your hoe out and nip those tiny seedlings in the bud.
Sodic (salty) soils are a big problem throughout inland Australia. Unless you’re keen to subsist on saltbush and saltbush-reared lamb, it’s a good idea to work on amending salty soils to make them suitable to a wide range of crops. Gypsum is ideal. It has little effect on soil pH, but it provides essential calcium and as it dissolves, releases calcium ions that displace sodium. Apply gypsum about a fortnight before planting cool season vegies. Liquid and granular forms are available from nurseries and produce supply stores.
May is a great month to order bare rooted plants, and to prepare planting sites in advance of their delivery in winter. If you have good quality site soil, you don’t need to do much. Just dig a reasonably sized planting hole, perhaps add some compost, backfill and cover with mulch until plants arrive. If your soil is poor, dig a bigger hole and improve issues like drainage and fertility. Add compost, some rotted manure, and other amendments as required by the plant. Again, backfill, then cover with a blanket of mulch. This kind of prep creates the ideal conditions for getting bare rooted plants off to a cracking start.