March Gardening Tasks

With the long summer months slowly passing into the cooler and calm autumn days of March, it is time plan and plant new flowers and veggies that will be in the garden for the next few months.

Like September, March is a prime sowing month, and the cooler days means working in the garden is a pleasure.

General Tasks

Water at least once a week. As nights get cooler, water earlier in the day.
Rake up fallen leaves and add to the compost, alternating with green lawn cuttings or leaves for a nutritionally well-balanced compost.
March is the best time to make hardwood cuttings, deadhead summer annuals and divide overgrown perennials.

Sowing

Sow now directly into well-prepared soil: Californian poppies, Flanders poppies, Shirley poppies, nemesias, lobularias, forget-me-nots, English daisies, calendulas, cornflowers, candytufts, godetias, Namaqualand daisies, bokbaaivygies.

Planting

Hellebores and Japanese anemones are lovely perennials for winter and spring colour in light shade that should be planted now.
Add the following jewels to your garden now: cosmos, Echinacea purpurea, Amaryllis belladonna (March lily), black-eyed Susan, and all the Plectranthus species and varieties.
As soon as the autumn rains have fallen in the Western Cape, gardeners there can start planting restios, ericas, proteas, leucadendrons, pincushions and buchu into the warm, moist soil.
Plant Wild dagga (Leonotis leonurus) in sun or semi-shade. It is an important food and nectar plant for sunbirds, bees and butterflies during autumn and winter.
Carry on planting traditional ‘summer seedlings’ like dianthus and petunias, as they will supply colour all winter too.

Bulbs

Buy your winter- and spring-flowering bulbs now, but only plant them when the soil temperature has cooled – usually only after Easter.

Feeding

Feed all shrubs as well as the lawn with a potassium-rich fertiliser like Atlantic’s Bio Ocean, to strengthen the cells and stems before winter comes.
Don’t feed dry plants. Water well before you start.
Choose the correct fertilisers for flowering shrubs, foliage plants and lawns.
Fertilise in cool weather.
Always follow the application instructions on the product
Don’t allow granular fertiliser to fall on the stems and leaves of plants as it can cause burning.
Spread the fertiliser evenly over the dripline of large shrubs and trees to reach the feeding roots.
Irrigate lawns and shrubs immediately after applying granular fertilisers.

Dividing And Replanting

Start lifting and dividing overgrown perennials like dietes and liriopes.
Lift and divide thick clumps of agapanthus. Break the clumps into smaller pieces, snip the old roots and leaves back and replant them in soil enriched with compost and bonemeal.
Divide daylilies once their summer-flowering flush is over. Lift the plants using a garden fork and split them into individual segments. Cut the foliage back so that each plant is about 20cm tall. Prepare the soil before planting back with bonemeal and compost. Plant the new splits about 15 – 20cm apart.

Plant Cuttings

Take semi-hardwood cuttings of bougainvilleas, acalyphas, crotons, ixoras, hibiscuses and Mackaya bella.
Take cuttings of rambling roses.
Take some last cuttings of frost-sensitive plants like plectranthus, begonias and coleus. Keep them well protected in winter.

Pruning

While autumn is not the time for massive pruning, it is the time to do an annual clean-up. Get rid of all the tired summer growth to revitalise your whole garden.
Hedges also need a good clip in autumn, unless they are expected to flower soon.
While it is fine to tidy up most plants, rather avoid the pruning of frost-sensitive and subtropical plants if you are in an area that has cold winters. Also be careful not to prune shrubs that flower in autumn and early winter – those must be pruned in spring.
Cut back spent heliconias and cannas, and cover root areas with a mulch of compost or well-rotted kraal manure.
Cut back the flowering stems of perennials like Michaelmas daisies, Shasta daisies and physostegias (obedience plant) to ground level.
Try to get the most out of summer’s annuals and perennials by deadheading them regularly.
If the sweet peas that you have already sown are growing well, remove some of the tendrils that they produce. This will encourage larger and stronger blooms.

Lawns

Pests

Start applying a systemic insecticide like Koinor to conifers, to guard against Italian cypress aphids. It is easy if you just do it as a soil drench.
There will still be a large number of snails about, so keep your bait traps full at night.

March Rose Tasks

In autumn, there is more dew on the leaves, creating the perfect condition for black spot. Protect the roses by spraying once a month with an organic fungicide.
Top up the nutrients by fertilising in mid-March. Roses with light green or yellowish leaves are lacking in nutrients and are more susceptible to black spot.
Water roses deeply at least once a week.
Identify roses in the wrong place and start preparing a new position for them, for transplanting in May or June.
Don’t cut more than 50 percent of rose blooms off a bush at the same time, it puts too much stress on the roots, and the rose suffers.
Keep on cutting off dead flowers to encourage the rose to re-sprout.
If the soil around the roses is compact, spike the soil using a garden fork. After spiking spread compost over the area and water well. Fertilise and water again.
If you notice crinkled leaves and deformed flower buds caused by a thrips infestation, spray with an organic insecticide. This will also prevent aphids.

March Veggie Sowing Guide

Highveld and KwaZulu-Natal Midlands

Beetroot, Chinese cabbages, carrots, cauliflower, kohlrabi, leeks, lettuce, onions, parsnips, radishes, spinach and Swiss chard, turnips

Middleveld (Pretoria and other less frosty areas)

Beetroot, Chinese cabbages, cabbages, carrots, cauliflower, celery, kohlrabi, leeks, lettuce, onions, parsnips, radishes, spinach and Swiss chard, turnips

Eastern Cape and Little Karoo

Chinese cabbages, cabbages, carrots, cauliflower, celery, kohlrabi, leeks, lettuce, onion, parsnips, radishes, Swiss chard, turnips

Western Cape (and Southern Coast)

Beetroot, Chinese cabbages, cabbages, carrots, cauliflower, celery, kohlrabi, leeks, lettuce, parsnips, radishes, spinach and Swiss chard, turnips

Northern Cape and Great Karoo

Beetroot, Chinese cabbages, carrots, kohlrabi, lettuce, onions, parsnips, radishes, spinach, Swiss chard, turnips

Lowveld and KwaZulu-Natal coast

Bush beans, runner beans, beetroot, brinjals, cabbages, capsicums (sweet peppers and chillies), carrots, cauliflower, celery, cucumbers, kohlrabi, leeks, lettuce, onions, parsnip, garden peas, pumpkins and Hubbard squashes, radishes, rhubarb, spinach and Swiss chard, bush and trailing squashes, tomatoes, turnips

Veggie Garden Tasks For March

Keep harvesting summer crops as this keeps them in production mode.
Fertilise summer-fruiting crops and beans with a potassium-rich fertiliser.
Sow autumn and winter crops. Make space by pulling out spent summer crops and renew beds with compost and mulch.
Plant cool-season herbs like chives, coriander, calendula and rocket. Mustard can also be sown in March and April.
Give a last application of fertiliser to long season crops like chillies and peppers, tomatoes, brinjals and squashes.
Water regularly – drying out affects the flavour and reduces productivity.
Brassicas need to be well established before winter. Fertilise every two weeks with a nitrogen-rich fertiliser at half strength to encourage good growth.
Sow nasturtiums between cabbages and cauliflowers to act as a trap crop for aphids.
Cut down asparagus foliage and add to the compost, along with fallen leaves and grass cuttings.
Cut back herbs that have flowered (basil, marjoram, oregano) to encourage a second flush of leaves.
Feed fruit trees that have just finished fruit production. Mulch and water well afterwards. Do not allow citrus to dry out – they need moisture while the fruit is developing. If the fruit looks too heavy and starts to bend the tree’s branches, thin out some fruit.
Dig and prepare planting holes for new deciduous fruit trees – fresh stock will be available in nurseries.
Control mildew on tomatoes, runner beans and long-season squashes like butternut and gem squash with an organic fungicide.
In hot, dry gardens, check for red spider mite. Wet the underside of the leaves, and if mites are noticed spray underneath the leaves with an organic insect spray.
Check for pests, especially aphids, on young brassica plants and use an organic insecticide.