April growing guide
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Autumn is a fantastic time to be out and about in your garden. Usually, in most parts of Australia, the weather starts to become milder but there still remains a significant number of sunny days to potter around in.
If your gardens survived the recent heavy rains and flooding, the lingering warmth has everything growing like mad, and gardens are looking lush and green as ever. This is a busy month in the garden, with lots of gorgeous, colourful plants to add to your planting list, and a bunch of odd jobs to attend to before the crisp autumn air starts to move in.
After heavy rains or flooding
The above-ground devastation of heavy rain is obvious. There's destruction of buildings, erosion of valuable topsoil and the complete removal of vegetation. Although the loss of vegetables and flowers is heartbreaking, the real damage that flooding causes to gardens lies underground.
Healthy soil provides plants with anchorage, nutrients, oxygen and water. Once this soil becomes saturated, all the air pockets are removed. Studies show that within 24 hours of immersion, the root hair zone, which is right at the tip of the roots, begins to die, leaving plants vulnerable to a range of diseases.
Given the damage that waterlogged soil can so quickly cause plants, it's a good idea to undertake a bit of restoration work.
Let the soil drain naturally first - this will take longer for clay soils
A shortcut is to add lots of coarse organic material to the soil. Compost is always the best for this, but in a crisis the rules change and mulches such as pine-bark create an artificial pore structure which lets the air get back into the soil. It has one disadvantage though - it removes some nitrogen from the soils as it breaks down.
Waterlogged soils can become acidic. To overcome this, add a handful of lime per square metre on the surface.
Apply blood and bone or some poultry manure - about a handful per square metre will kick the soil back into life.
Once soil is back in good condition, it's time to think about what to grow again.
Veggies
It is not too late to get your winter vegetables in, especially if you get them down in early April. Vegetables such as broccoli, cauliflower and cabbage and your leafy Asian style veggies really need to go in now if you want to get the best out of them throughout winter.
Versatile spring onions are one of the easiest-to-grow veggies in the garden. Grown all year round in most climates, they do particularly well in all but the coldest climates, when planted in autumn. Sow seed into shallow drills and cover with a thin layer of soil. Water gently and keep moist until they sprout. As the plants grow, thin out the clumps and use the thinnings in salads and sandwiches.
Get in some root veg like beetroot, turnips, radish, carrot and parsnip and make a start with alliums such as leeks and chives. Don’t forget lettuce, endive and silverbeet for warm-winter salads.
It’s time to get happy with herbs, so try some parsley, rosemary, marjoram and thyme. You could give mint and lemon balm a go as well, but be careful to contain them as they can take over!
Cut back the feathery foliage of asparagus, now that the cooler weather has turned the leaves yellow and brown. Chop the lot, leaving about two inches above the ground, and mulch well.
What to plant in the veggie patch.
Beetroot, broad beans, broccoli, Brussels sprouts, burdock, cabbage, carrots, cauliflower, chives, endive, garlic, Jerusalem artichoke, kale, kohl rabi, leeks, lettuce, mangle-wurzel, mizuna, mustard greens, onion, oregano, pan choy/ bok choy, parsley, peas, snow peas, radish, rocket, salsify, shallots, silverbeet, spinach, swedes, turnips and salad greens.
Fruit & trees
Autumn, and in particular April, can be a great time for planting trees because trees really do require good amounts of water to take root. Planting now will give them a month or 2 of good, sunny weather while still receiving some good rains, and then lapping up the rains of winter. The milder weather will also help because the trees won’t experience sun damage as easily before they have the root system to cope with it.
It’s a good time to spread a light organic fertiliser around your shrubs and trees. Though they’ll receive Winter rains and won’t be growing as much, they still require nutrients to survive the cooler winter.
Start harvesting autumn raspberries, which should keep cropping right through until winter. If other critters are getting to the fruit before you are, some taut, well-installed netting should keep your crop safe.
Persimmon fruits are starting to turn bright orange, so it’s time to harvest. Non-astringent varieties can be eaten straight away, but let astringent fruits go soft and squishy before tucking in.
Natives
Divide clumping native plants like kangaroo paws, dianellas and lomandras by cutting into sections with a sharp spade, leaving around 5 shoots per cutting. Pot up in a protected spot.
Pop in a Prostanthera rotundifolia, the round-leaf mint bush. Native to southern Australia, this tough, tidy shrub is perfect in pots, and the foliage aromatic and edible.
Try growing Desert Flame, Chrysocephalum apiculatum, a perennial Australian native that brings a blaze of colour to the garden with golden yellow flowers and silvery grey foliage. It's a hardy, maintenance plant that provides stunning ground cover and can grow 20–30cm tall. It prefers temperate climates and grows best in full sun or part shade and most soil types.
Flowers
Right now is a great time to prune your summer flowering perennial plants, like lavender, ready for the winter quiet. However it’s still too early for roses because if you prune them now, they’ll start growing back too soon and won’t perform as well. Save your roses for June-August pruning. Continuing to dead head roses is important though.
Plant spring-flowering bulbs, such as anemone, babiana, bluebell, Dutch iris, freesia, ixia, jonquil and ranunculus now to give them plenty of time to get set and grow ready for a beautiful showing come September. Daffodil, grape hyacinth, hyacinth and tulip bulbs need a chilling period, so should be kept in the fridge for six weeks first.
For months of colour right up until Christmas, plant your favourite alyssum, candytuft, Canterbury bells, cineraria, cornflower, lobelia, lupin, pansies, penstemon, polyanthus, poppy, snapdragon, sweet pea, verbena, violas and wallflower for winter colour.
Avoid fertilising camellias and azaleas in April. Why? Feeding now will stimulate leaf growth, but might cost you buds and flowers down the track.
Pest watch
To help prevent fruit trees from being reinfected with fungal disease next summer, remove any “mummified” fruit still hanging on the branches and dispose of them in the bin. Peaches and nectarines are especially prone to brown rot, and mummified fruit is a major source of fungal spores.
Keep an eye out for aphids and other insect pests, especially on herbs, vegetable and flower seedlings. Use an organic spray such as Pyrethrum to control them or better still, plant nasturtium, dill and marigolds to attract ladybugs to gobble them up.
Cut out and dispose of galls (swellings) on citrus trees to help eradicate gall wasps.
Little bit of everything else
With autumn rain comes chickweed (Stellaria media). This plant is rampant in shady parts of my garden during the cooler months, but fortunately, it’s one of the best weeds you can accommodate. Chickweed leaves are edible, and make a nice addition to salads. And as the name suggests, chickens love it. I regularly pull a few plants where they aren’t wanted and throw them into the chook run. The result is healthy birds that lay eggs with brilliant orange yolks.
The best thing about autumn is you won't have to mow your lawn as often as you do in spring and summer but that doesn't mean you can neglect it all together.
Check your lawn and make sure any weeds are picked or sprayed with an organic spray. Repeat the treatment if necessary in a months time.
Aerate the lawn with a garden fork and scatter lime lightly over it. This sweetens the soil after many years of lawn food application.
Rejuvenate tired lawns with an autumn feeding to ready them for the onset of cool winter weather.