March is an exciting and busy month in the garden with preparations for winter and spring displays of annuals and bulbs, vegetable patches to be enriched and sown, trees and shrubs to be selected and planted and some end-of-summer pruning to be done.
Autumn is one of the best times to plant trees and shrubs. Dig holes twice the size of container.
Remove any faded summer annuals that are past their best and make sure all weeds come out.
Condition soil by spreading compost or manure generously all over beds, with just a sprinkling of lime or dolomite to sweeten soil. Dig over thoroughly with a fork and turn compost in below the surface until soil has regained a good tilth. It should be crumbly with no hard, compacted patches. Rake it smooth and leave a week or so before planting. Aim for a well-composted soil about 40 cm deep, deeper for deep-rooting trees.
March is the busiest month for sowing seeds of spring flowers and vegetables. Prepare beds and seed boxes. If selecting a new site, consider points such as wind protection: remember wind comes from the south-east throughout most of the dry season. Keep beds away from routes of children and dogs. Make beds accessible to water points.
Tips for vegetables: don't oversow - base the area planting on what you need; have basic pest control chemicals on hand; don't buy seed not contained in foil packets.
A general clean-up is advisable after the wet season and before the vigorous growth of the dry season begins.
If planting annuals, fork over and fertilise the area. Apply blood and bone or animal manure and a dressing of dolomite. Also apply a general-purpose fertiliser, broadcast, 150-200/m, and well incorporated with soil about a week before planting. Several applications of complete liquid fertiliser are also beneficial. This rate may seem high by southern standards, but northern soils in many areas are devoid of nutrients.
Dahlias, summer annuals and roses are bright at the moment. Plan now for a similar display in spring.
Hardy ferns such as some of the Blechnum species thrive in cool, moist spots where many others fail. Give them open, peaty soil.
Dahlias and chrysanthemums need regular watering and plenty of blood and bone; the liquid form is most effective. Disbud chrysanthemums for bigger blooms. Protect from wind by staking.
Carnations give much sought-after winter flowers. Start feeding with five parts of blood and bone to one part sulphate of potash. Cut down on nitrogen (good growth but few flowers).
In cold zones
March signals summer's end. Cool nights slow up most growth. Stop feeding any flowering plants now.
Remove all spent flower heads. Lightly prune to strong outward-pointing buds and examine them for fungus diseases such as mildew and black spot. Spray with fungicide if necessary. Water and fertilise with packaged rose food regularly to boost the autumn flush of blooms.
Shrubs and trees
Tidy up shrubs and climbers rampantly leafy after summer rains. Wistarias need long summer canes and tendrils cut back, leaving only short flowering spurs with two or three pairs of buds.
Prune cotoneasters' long straggly water shoots so that developing berries are not shaded.
Water camellias deeply at least once a fortnight and fertilise with blood and bone or rotted cow manure.
Prune newer varieties of hydrangea late February to early March. Leave unflowered stems uncut to bloom next season. Prune old-type hydrangeas in need of hard cutting back to lowest pair of buds. In southern climates late summer pruning allows time for plants to grow and produce blooms next summer. Keep watered and apply organic mulch and complete fertiliser.
In tropical zones
Prune shrubs. Crotons especially benefit from shaping. They can be cut back fairly hard to improve their shape and keep them bushy. Croton sap stains permanently, so wear old clothes.
Sharpen secateurs then prune climbers: chain of love (Antigonon), jasmine, manettia and solanum after flowering.
Fertilise azaleas, camellias and roses. Trim off scraggy growth and spent blooms, then gently work over soil around plants to eliminate weeds and
This is the main planting month for spring flowering bulbs in temperate zones.
Good autumn rain quickly revives jaded lawns. Aerate with a long-pronged garden fork or a special hollow tine fork to help get water and fertiliser into soil. Apply lawn fertiliser. Sow new lawns if water is no problem. Paving stones or a lower groundcover could improve patchy areas of heavy use and over-shading.
In tropical zones
Commence dry season maintenance of lawns now the monsoon trough is moving away. Paspalum notatum lawns particularly will benefit from a thorough raking. Top dress with an NPK fertiliser, 60-70 g per metre, before raking. As soil dries out and sunlight increases, growth is generally prolific. Keep your lawn mown to its usual height. Light monthly or bimonthly applications of nitrogen are advisable.
In cold zones
Start preparing soil for lawn-sowing in April. This includes ripping and rotary hoeing and removal of stones, rubbish and perennial weeds such as couch and paspalum. Leave for a few weeks to allow weeds to germinate before final hoeing, levelling and seeding.
Rake up and burn fallen fruit from around the bases of trees. These are a haven for fruit fly which is a serious pest.
Trim any branches broken by crop weight and paint cuts with wound dressing. Keep trees deeply watered in hot, dry days towards autumn to prevent premature leaf drop.
In cold zones
Cut raspberry canes that fruited this season right down to ground level. Dispose of dead or diseased canes leaving about five or six canes to a plant.
Most strawberries have finished fruiting so peg down runners from parent plant. Allow only one runner per plant from one-year old plants.
Prepare soil for another crop by turning it over and working in rotted compost or manure. Add complete plant food and rake surface until fine and crumbly.
Test pH if you have a kit or meter and adjust up or down.
Pick mature pumpkins and hang in dry airy place.
In cold zones
The vegetable garden is ending summer production. After each crop, dig discarded vegetable matter back into soil to improve soil and help maintain a good moisture level.
Prepare a seed bed for sowing early maturing onions.
Select a position for planting strawberries.
Keep cabbage and cauliflower growing with regular water.
Lift potatoes and store.
1. Hose off aphids on chrysanthemums, dahlias and roses or spray with pyrethrum. Remove grubs, especially caterpillars, on vegetables by hand.
2. Give lemon trees a second white oil spray against scale and associated sooty mould. To avoid leaf damage, water well the day before and after spraying, and do not spray on days over 30°C. Check that bud union is above ground and mulch is clear of trunk. If collar rot is present, cut away all decayed bark and wood and treat with an approved chemical.
3. Spray thrip on azaleas, camellias and roses with pyrethrum.
In cold zones:
Watch for cabbage butterfly in vegetables and spray for codling moth on fruit trees until harvest.
Source: Successful Gardening Month by Month (Murdoch Books)