Iceland Poppies. Picture courtesy -
Bedding Plant Growers Association.

All Regions

August is when you really start reaping the rewards of your carefully planned winter and spring flowering garden, and as the month progresses the displays will just get better and better; banishing even the worst of the winter-blues. 

August can be a very windy month so ensure that all your standard plants and young trees are securely staked. If you have not mulched your beds yet to conserve moisture, August is a good time to do so.

As the days begin to warm up and the buds start to swell, you can gradually increase the amount you water your garden.  
 

Fertilise all your shrubs and trees at the end of the month with a good general purpose fertiliser like 2:3:2 and water it in well. 

Lime-rich soils cause iron deficiencies, resulting in yellow leaves (chlorosis) and susceptible plants like yesterday-today and tomorrow and gardenia can be treated with iron chelate; followed by a dressing of Epsom salts two weeks later. Spraying regularly with a trace element mixture like Trelmix is also beneficial. Mulch all your acid loving plants with acid compost. 

Yesterday-today and tomorrow (Brunfelsia)

Cirus psylla

Fruit trees like peaches, apricots, plums, nectarines, pears and apples will be coming into flower this month, so mulch them with compost and feed with a granular organic 3:1:5 fertiliser; watering it in thoroughly. For young trees use about 100g per tree and for mature trees about 200g. In the summer rainfall regions water deeply every 10 days. If your trees were infected with peach leaf curl last season, spray them with a suitable fungicide before they come into bloom.

Citrus trees should be fed with organic 3:1:5 or 2:3:2 and will benefit from a dose of iron chelate; followed by a dressing of Epsom salts two weeks later. Spraying regularly with a trace element mixture like Trelmix is also beneficial. If citrus psylla was a problem last season, resulting in unsightly bumps on the leaves; spray as soon as the new, young growth emerges, paying particular attention to the new leaves as well as the undersides of the leaves.

Tropical fruits like figs, avocados, pineapples, paw-paws, granadilla and mangoes will also benefit from a feeding with 3:1:5. Weed out the male paw-paw plants as soon as they come into flower, leaving only one male for every 5 females.

Feed your strawberries with 2:3:3 and water well. In the warmer summer rainfall regions it is time to sow Cape gooseberries.

Continue to feed your winter and spring flowering annuals and remove the spent blooms regularly, to encourage the formation of new flowers. Sweet peas and Iceland poppies flower for longer if picked regularly.

In warm regions you can start sowing summer seeds in trays now. Try alyssum, ageratum, asters, amaranthus, cosmos, candytuft, celosia, cleome, bedding dahlias, gaillardia, lobelia, lavatera, phlox, marigolds, nicotiana, godetia, salvia, portulaca, verbena, zinnia, torenia, nigella and California poppies. Grouping your seedlings together according to their watering requirements, will save you a lot on water.

Become a subscriber to www.gardeninginsouthafrica.co.za today, to find detailed information on growing your favourite summer flowers  To subscribe or read more

Love-in-a-mist (Nigella)
Picture courtesy Nancy Carman

It is time to plan your summer vegetable patch and to prepare the beds. Vegetables must grow quickly for optimal flavour and quality, so prepare the beds well. Thoroughly dig over the entire bed, adding lots of compost and 100 grams of organic 2:3:2 fertiliser per square metre. Rake the bed level, water well and allow the bed to lie for at least a couple of days before sowing seed, as some large seeds like beans can be damaged by direct contact with fertiliser. The perfect soil for growing vegetables is a loose crumbly well-drained soil that still retains moisture and nutrients. 

Vegetables need more attention, regarding the soil pH, than flowers or shrubs. Most vegetables prefer soil with a neutral pH of 7.0 to slightly acid soil pH 5.5 to 6.5.  Lime is used to make the soil less acid but should be applied one month before adding compost, manure or fertiliser and before sowing or planting. Lime should only be required every three or four years if you practice crop rotation and maintain a healthy soil. Lime is traditionally spread on the surface of the soil for rain to wash it in, but on medium to heavy soils, it is better to dig it into the topsoil.

In all but the subtropical regions, August is a good month to sow vegetables like eggplants, tomatoes and peppers into seedling trays, for planting out as soon as all danger of frost is over. These seeds will not germinate unless they are kept warm, so place the trays in a warm, sheltered spot during the day and bring them indoors at night.

Feed your broccoli with a high nitrogen feeder after you have harvested the main head as this will encourage the growth of secondary shoots. Lift and divide crowded clumps of herbs and prune them back before replanting into composted soil.

Find out all you need to know about growing your own fresh, healthy vegetables this summer. "Growing Vegetables in South Africa" is a practical and easy to understand book that includes many tips for organic gardeners, and so much more. To order or read more
 

If you wish to lift and store winter and spring flowering bulbs for next season, it is essential that you feed them every two weeks with a high potassium fertiliser, until the leaves die down naturally. Do not cut off the leaves as this is a critical time in the life of a bulb, as it is now that the new flower embryo is developed inside for next season’s blooms, and nutrients are essential.  When all the leaves are dead you can lift them. Select only healthy, plump bulbs to store and dry them thoroughly in a shady, well-ventilated place, before storing them in a cool dark cupboard.

Buy your summer bulbs as soon as they are available and store them in a cool place until planting time in spring. It is time to plant Amaryllis bulbs but beware; garden moles love them, so if you have a mole problem, plant them into special pots that are available in the garden centres, or make a basket in the soil with chicken mesh.  Leave about 3cm of mesh above the ground, to stop the moles from going over the top.  To encourage stored dahlia bulbs to shoot, take them out of their boxes; dust them with flowers of sulphur to help prevent fungal infections and loosely cover them with soil, add a sprinkling of general purpose insecticide granules and water lightly.

Delay pruning your roses until mid or late August if you live in a very cold region, but in all other regions you should have finished pruning.  If not, do so now. Start watering the bushes deeply about twice a week.  If your roses are still dormant you can spray them for a second time with winter strength lime sulphur (1 part lime to 8 parts water) but ensure that your plants are not already in leaf. Lime sulphur will burn leaves, so wash any spray off of any plants growing underneath your roses. Mulch the roots of your plants with mature kraal manure or compost; keeping it away from the stems to avoid collar rot. Feed with an organic fertiliser that is high in nitrogen like 8:1:6 and water thoroughly. Take hardwood rose cuttings now as the sap will soon begin to rise.

Garden & Home Rose
Picture courtesy Ludwig Roses

Day Lily 'Mauve Mini'
Picture courtesy Hadeco

If you desire very dark blue hydrangeas this summer you can sprinkle some aluminium sulphate around the roots of your plants now or spray it onto the leaves by diluting 25 grams of aluminium sulphate into 5 litres of water; repeating every two weeks until January.

Divide and replant overcrowded perennial plants now into well-prepared beds. Gently pull apart the actively growing plants from the outside of the clump, choosing only healthy looking pieces and discarding the woody central part of the mother plant. Mulch the clumps with compost or manure and feed with an organic 3:1:5 or 2:3:2 fertilisers; watering it in thoroughly afterwards.

Re-pot any indoor pot plants that are looking tired into a slightly larger pot. Most potted plants like to be a little pot bound and do not like being planted into pots that are too large. Ensure that you use a good potting soil and add some bone meal to the soil.

Summer Rainfall Region

August is an unpredictable month with warm sunny days and then sudden, late frosts.  Water the garden regularly during this dry period, especially your spring flowering plants. Check you irrigation system and make any repairs before summer.

Spring is the best time to sow lawn seed or to plant instant lawn in these regions so prepare the soil this month. Dig over the area, about 20cm deep, adding generous amounts of compost together with a dressing of organic fertiliser like 2:3:2. Rake the area level, water it lightly and then let it lie until next month  Do not scarify and fertilise your established lawn until all danger of late frost is  over, as the new blades are easily burnt. Runner lawns like Kikuyu must be mowed extremely short and scarified with a hard rake or broom to remove all the old dead mat of grass.  Spike the entire area with a lawn-spike or do it manually using a garden fork and driving it into the soil about every 30cm. Water thoroughly a day before top dressing with a lawn dressing and feeding with a balanced organic lawn fertiliser and watering thoroughly again.  Do not top-dress with more than 3cm of soil. Berea lawns should not be mown too short and lawns like Kentucky Blue or tuft-type lawns like All Seasons Evergreen or Shade Over should never be scarified. If you feed your Kikuyu lawn regularly in early summer it will grow quickly and smother the weeds. Remove weeds as soon as they appear and before they get a chance to set seeds.

Do not prune your evergreen shrubs until all danger of frost is over and when you do, remember not to prune your spring and early summer flowering plants.  Fuchsias are pruned in late August or early September, when all danger of frost is over.  A general rule is to cut back by two thirds and remove dead, weak stems.

In the cold regions you can start sowing early summer vegetables and flowers into trays, as long as they can be kept in a warm, protected place.  If you don’t have a protected place, wait until September. Summer seeds can only be sown directly into garden beds when all danger of frost is over. In the more temperate regions you can start sowing Cape Gooseberries, plant your first crop of potatoes, and divide your overgrown herbs.


Gazania 'Gazoo'

Dry Continental Region

August is an unpredictable month with warm sunny days and then sudden late frosts.  Water the garden deeply and regularly during this dry period, especially your spring flowering plants.

Spring is the best time to sow lawn seed or to plant instant lawn in these regions so prepare the soil this month. Dig over the area, about 20cm deep, adding generous amounts of compost together with a dressing of organic fertiliser like 2:3:2. Rake the area level, water it lightly and then let it lie until next month. Do not scarify and fertilise your established lawn until all danger of late frost is over, as the new blades are easily burnt. Runner lawns like Kikuyu must be mowed extremely short and scarified with a hard rake or broom to remove all the old dead mat of grass. Spike the entire area with a lawn-spike or do it manually using a garden fork and driving it into the soil about every 30cm. Water thoroughly a day before top dressing with a lawn dressing and feeding with a balanced organic lawn fertiliser and watering thoroughly again.  Do not top-dress with more than 3cm of soil. Tuft-type lawns like All Seasons Evergreen or Shade Over should never be scarified. If you feed your Kikuyu lawn regularly in early summer it will grow quickly and smother the weeds. Remove weeds as soon as they appear and before they get a chance to set seeds.

Delay pruning your roses until the middle or end of August if you live in a very cold region.  Do not prune your evergreen shrubs until all danger of frost is over and remember not to prune your spring and early summer flowering plants. Hydrangeas can be pruned if they were not pruned last summer. Fuchsias are pruned in late August or early September, when all danger of frost is over. A general rule is to cut back by two thirds and remove dead, weak stems.

You can start sowing early summer vegetables and flowers in trays, if they can be kept in a warm, protected place. If you don’t have a protected place, wait until September before sowing seed. Summer seeds can only be sown directly into garden beds when all danger of frost is over. 

Soils in arid climates tend to be alkaline, with a pH factor of 7.0 or higher. This is caused by the high percentage of lime (calcium carbonate) in the soils of these regions. The main problem associated with alkaline soils is that certain essential nutrients, particularly iron and zinc, become unavailable to the plants. If the soil is mildly alkaline (pH 7.5) you have nothing to worry about, but the higher the pH, the harder it will be for you to find appropriate plants that will survive in your garden. If your soil is alkaline, try sowing seeds of achillea, Californian poppies, Candytuft, campanula, yarrow, sweet william and dianthus this summer. Other plants that grow well in alkaline soils are euphorbia, westringia, lavender, iris, kangaroo paw; garden pinks, clematis, potentilla and yarrow. Herbs like oregano, sage, rosemary and thyme should also thrive.

Subtropical Regions

August can still be a very unpredictable month. Mulch all your flowerbeds to help conserve moisture and water and feed your shrubs regularly. Check you irrigation system and make any repairs before summer.

If you have not scarified your lawn yet do so now. Runner lawns like Kikuyu must be mowed extremely short and scarified with a hard rake or broom to remove all the old dead mat of grass. Spike the entire area with a lawn-spike or do it manually using a garden fork and driving it into the soil about every 30cm. Water thoroughly a day before top dressing with a lawn dressing and feeding with a balanced organic lawn fertiliser and watering thoroughly again. Do not top-dress with more than 3cm of soil. Durban or Berea lawns should not be mown too short and lawns like Kentucky Blue or tuft-type lawns like All Seasons Evergreen or Shade Over should never be scarified. If you feed your lawn regularly in early summer it will grow quickly and smother the weeds. Remove weeds as soon as they appear and before they get a chance to set seeds.

Feed your avocados, paw-paws, pineapples, granadillas, mangoes and figs. Weed out the male paw-paw plants as soon as they come into flower, leaving only one male for every 5 females.

Prune your winter flowering plants and bougainvilleas when they have finished flowering and lightly prune other evergreens that may need it. Do not prune spring flowering plants.

Sow or plant alyssum, aster, cleome, impatiens, salvia, cosmos, verbena, marigold, dianthus and bedding dahlias.
Sow vegetables like lettuce, carrots, beans and squashes directly into well-prepared beds.



Alyssum white

Winter Rainfall Region

The northwest winds are still howling, but take heart; spring is on the way and heralds the most spectacular display in the floral kingdom of the Cape. Finish your pruning by the middle of August.  Remember, don’t prune your spring flowering shrubs and roses.  Fuchsias are pruned in late August or early September, when all danger of frost is over.  A general rule is to cut back by two thirds and remove dead, weak stems. Winter pruning of roses should be completed by the middle of August.  As soon as the bushes come into leaf, spray with a good fungicide to prevent black spot and powdery mildew. Do not prune your bougainvilleas until the end of November but feed them with 2:3:4 or 2:3:2 now.

Lawns in this region are scarified and top-dressed in autumn but once the soil dries out a bit you can top dress lightly and fertilise with an organic lawn fertilizer that is high in nitrogen. If you feed your Kikuyu lawn regularly in early summer it will grow quickly and smother the weeds.  Remove weeds as soon as they appear and before they get a chance to set seeds.  If there were drainage problems in your lawn this winter, fix them as soon as the soil dries out. Level out any hollows where water collects by cutting out squares of turf and filling up the hollows with compost mixed with river sand before laying the lawn again. It may be necessary to install a proper drainage system in areas with serious drainage problems.  To get rid of moss in lawns, mix two tablespoons of sulphate of iron into 5 litres of water and water it in; repeating 7 days later.
 
Prepare your beds to plant and sow summer flowering annuals. Add generous quantities of compost and a sprinkling of organic 2:3:2 and bone meal. Mulch all your other beds generously with compost and fertilise with 2:3:2. You can start sowing early summer vegetable and flower seedlings in trays if you have a protected place for them.  Sow and plant ageratum, alyssum, begonia, candytuft, dianthus, delphiniums, California poppy, foxglove, godetia, gaillardia, lobelia, nicotiana, penstemon, snapdragons, viscaria and lychnis. Vegetables like beans, radish, cabbage, broccoli, cauliflowers, celery, carrots, cucumber, egg plant, leeks, spanspek, parsnip, peppers, pumpkin, lettuce, tomato, beetroot spinach and herbs.