August is a busy month in the garden

Bokbaaivygie Picture courtesy Maria KlangBokbaaivygie Picture courtesy Maria Klang

What to do in your garden in August

All Regions

August may be a windy month, and can still get miserably cold, but it is also the month when you really start reaping the rewards of your carefully planned winter and spring flower garden; and as the month progresses the displays will just get better and better - banishing even the worst of the winter-blues.

 Because August is known as the windy month, ensure that all your standard plants and young trees are securely staked. There are many different types of tree stakes and ties, and different staking methods are used, depending on the size of the tree. Small trees can be secured to a wooden stake with a soft material like pantyhose or raffia, but larger trees will require very sturdy wooden or steel stakes and stronger ties. When securing your ties, ensure that they are not too tight, or they will damage the bark. Check the ties regularly during summer to ensure that they have not become too tight, causing damage to the trees.

To encourage the formation of new flowers continue to feed your winter and spring flowering annuals, and remove the spent blooms regularly. The more you pick sweet peas and Iceland poppies the more they bloom, so pick them often to brighten up your home and office. 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 in the garden according to their watering requirements and mulching will save you a lot on water bills.

(Highlighted plants are included in our Plant Index and members can click on the links for more information on the plants mentioned)

The large selection of flowering bedding plants available in South Africa enables us to have colour in our gardens throughout the year. Bedding plants allow you to incorporate a fresh "new look" every season by using different colour schemes and plant varieties. Combine this with the fast-maturing versatility of annuals, and your garden can become a canvas and you the artist!

Do you long to have colourful flowers in your garden throughout the year but are not sure which varieties to plant each season; or when to sow or plant them for best results? Are you also tired of wasting your money on seedlings that either die or do not give you the results you envisioned?

"Growing Bedding Plants in South Africa” is written especially for South African gardeners and covers everything you need to know about growing or your own seedlings. All 78 pages are packed with useful information; like the best planting and sowing times for each variety, as well as ideal germination temperatures and days to flowering.

This e-book is easy to understand, yet includes everything you need to know about successfully sowing and growing beautiful bedding plants in South Africa. I hope it will inspire you to create a beautiful flower garden, no matter how large or small. Whether you sow your own seeds or buy seedlings from your garden centre, you will find growing bedding plants a most rewarding hobby. I know that the plants I have selected to include in this book will inspire the artist in you; and I hope that you will enjoy reading my book as much as I enjoyed writing it.
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Check all your bulbs, but especially your clivias, agapanthus and amaryllis, for early signs of lily borer. Tell-tale signs are clusters of tiny eggs underneath the leaves. Later the voracious zebra-striped caterpillars appear and start eating the leaves, working their way right down to the heart of bulbs themselves. Spray regularly with Margaret Robert’s biological caterpillar insecticide or another suitable eco-friendly insecticide. Click here to read more about lily borer.

If you wish to lift and store winter and spring flowering bulbs for next season, it is essential that you feed them with a high potassium fertiliser every two weeks until the leaves die down naturally. This is a critical time in the life of a bulb because as the leaves die down they feed the new flower embryo which is developing inside the bulb for next season’s blooms, and nutrients are essential. When all the leaves are dead you can lift the bulbs to store, selecting only healthy, plump ones. Dry thoroughly in a shady, well-ventilated place, before layering in cardboard boxes, between vermiculite or sawdust, and storing in a cool, dry place.

Summer bulbs like gladioli, amaryllis, arum lilies, tuberous begonias, caladium, canna cultivars, dahlia, Pineapple Flower (eucomis), Berg Lily (Galtonia), Spider Lily (Hymenocallis), Gayfeather (Liatris), liliums, tigridia and tuberose start arriving in the stores in August; buy them as soon as they are available to avoid disappointment, and store them in a cool place until planting time in September. Be warned however, moles love bulbs, and especially amaryllis bulbs; so if you have a mole problem plant them into special pots available in garden centres, or make a basket in the soil with chicken mesh; leaving 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 (available at chemists) to help prevent fungal infections, and loosely cover them with soil. Add a sprinkling of general purpose insecticide granules and water lightly. Split and divide established canna tubers this month and transplant into beds refreshed with compost and a dressing of bone meal or 2:3:2.

Find out more about growing your favourite summer bulbs in our bulb section – sign up as a member today! 

Somehow, as soon as the weather warms up the weeds magically appear en masse, so get stuck into the garden and weed them out before they set seed again. Mulching the soil not only conserves water but also helps to smother emerging weeds; so if you have not mulched your beds yet do so without delay. As the days begin to warm up 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 can cause iron deficiencies, resulting in yellow leaves (chlorosis); which is especially common in plants which prefer a more acid soil, like yesterday-today and tomorrow and gardenia. Plants with yellow leaves 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; as well as mulching all your acid loving plants with acid compost.

Picture courtesy Karl Gercens Picture courtesy Karl Gercens A beautiful lawn needs regular care throughout the year but especially in spring and summer; so if you want a gorgeous lawn this summer you need to start preparing now. In warm regions you can prepare your lawn in August, but in colder regions it is better to wait until September when all danger of frost is over. In the winter rainfall regions lawns are traditionally 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 fertiliser that is high in nitrogen.

Runner lawns like Kikuyu should be mowed extremely short and scarified with a hard rake or broom to remove the dead mat (use the rakings to mulch your garden beds or add them to the compost heap). Spike the entire area with a lawn-spike or do it manually using a garden fork, driving it into the soil about every 30cm. Please note that the above procedure only applies to runner-type lawns like Kikuyu, and will damage tuft forming grass varieties like shade lawn and evergreen mixes. Kentucky Blue and subtropical grasses like Berea, which is also called LM or Durban grass can be spiked and dressed but should not be cut too short.

Dressing runner type lawns in early spring with agricultural lime at +-200g per square meter, followed by a feeding with a good organic fertiliser like Blade Runner, once all danger of frost is over, will help to suppress aggressive weeds because the agricultural lime will improve the uptake of nutrients; making the grass grow so vigorously that most emerging weeds are smothered before they have a chance to establish themselves and set seed. If necessary, top-dress with a good quality weed-free lawn dressing but do not dress with more than 3cm of soil. Use the back of a metal garden rake to spread the lawn dressing over the area; this will even out any hollows.  Start feeding your lawn once all danger of frost is over; water thoroughly a day before fertilising and then spread a good organic fertiliser like Blade Runner over the entire area and water thoroughly again. For a perfect lawn all summer it is essential to feed every 4 to 6 weeks; to mow and water regularly; and to remove weeds as soon as they appear.

Established areas of tuft forming grass varieties like shade lawn and evergreen mixes can be very lightly mowed and then dressed and any hollows evened out with a good lawn dressing. Adding some bone meal to the lawn dressing will give your lawn a boost; and if there are any bare patches, seed can be added to the dressing. Water thoroughly and regularly thereafter until your lawn is well established.

Early spring and summer are a great time to sow lawn seed, and if you have a small garden, you should consider sowing an evergreen lawn. Evergreen mixes are available for both sun and shade and because they do not creep, will not invade your garden beds. They are also hardy, and as long as they can be watered regularly, will grow well throughout the country, except for very humid regions. To prepare the beds dig them over to a depth of about 20cm and add lots of compost and a dressing of 2:3:2. Rake the beds smooth and water gently. Once the soil has partially dried out, you can sow the seeds as recommended; rake the bed once again and water well. Ensure that the soil remains moist but not soggy until all the seeds have germinated, and allow the grass to establish itself well before mowing it for the first time. Please note that these lawns cannot be mown as short as kikuyu.

In most temperate parts of the country July is traditionally the time to prune and to plant out new roses; but you can still safely prune now if you get it done quickly before new growth begins in earnest. Delaying for another week or two is not detrimental but will result in your roses flowering later than normal. In very cold regions pruning is usually delayed until the middle of August. In the winter rainfall regions pruning starts from the end of July to August; and in warm subtropical regions you can prune from June to early August. (Read last month’s article)

In cold regions un-pruned roses may start shooting as a result of unusually warm weather, but because these shoots are usually on the tips of the branches and will be pruned off later, it should not be a problem and the dormant shoots below will shoot timeously in spring. If, however, you notice signs of red spider on the leaves and shoots, it is best to prune them off immediately to prevent serious infestations of the summer foliage.

When your pruned roses start showing signs of shooting give them a deep soaking and then water deeply every week; as the weather warms up towards the end of the month you can increase your watering to about twice weekly.  Mulch the roots of your plants with mature kraal manure or compost; keeping it well 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. To prevent early insect infestations spray your plants with an organic insecticide when the new leaves emerge; it should not be necessary to spray against fungal diseases this early in the season; unless you live in subtropical regions. If you wish to still take hardwood rose-cuttings, do so now because the sap will soon begin to rise.

In most temperate parts of the country pruning of deciduous fruit trees and grape vines is generally completed in July; but in very cold regions pruning is often delayed until the middle of August. In the winter rainfall regions pruning starts from the end of July to August; and in warm subtropical regions you can prune from June to early August. (Read last month’s article)

Frost bitten evergreen shrubs can be pruned in August when there is no longer a danger of late frosts; and when you do prune, remove all green branches from variegated shrubs right at their base, or the stronger growing green shoots will quickly overtake the variegated ones. As the weather warms cut back fuchsias by a third and mulch with compost; towards the end of the month, when they start shooting, start pinching out the growing tips to develop a bushier plant; and feed with a fertiliser high in nitrogen.

Do not accidently prune your spring and early summer flowering evergreen shrubs and climbers until they have finished blooming. If you are uncertain when a shrub flowers, it is always best to wait until it has finished blooming or fruiting before pruning.

Hemaerocallis 'Hearts Glee' Picture courtesy www.hadeco.co.zaHemaerocallis 'Hearts Glee' Picture courtesy www.hadeco.co.zaIf 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 groundcovers and perennial plants like agapanthus, Wild Iris (Dietes) and Daylily (Hemerocallis) now, transplanting them immediately 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 organic 3:1:5 or 2:3:2 fertilisers; watering it in thoroughly afterwards. If you’re ornamental grasses are looking untidy but do not need dividing, prune them back right down to the ground before they start shooting again.

Continue to treat your conifers for aphids until the first rains arrive, by regularly applying insecticide granules or a similar product around their roots.

Take hardwood cuttings now of conifers, roses and deciduous shrubs like weigelia and philadelphus.

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.

Continue to harvest your winter vegetables regularly and freeze or pickle what you cannot eat. Feed your broccoli with a high nitrogen feeder after you have harvested the main head as this will encourage the growth of secondary shoots. Broad beans bear prolifically and can be cooked in their soft pods when they are still young, so eat your fill. More mature broad beans are still delicious but need to be shelled; they can also be blanched and frozen. Much older pods can be harvested as dry beans if they are left on the plants until fully mature.

In frost-free regions you can continue to sow green beans, pumpkin and squash, cucumbers and melons; and a first sowing of maize and sweetcorn. In colder regions it’s is time to plan your summer vegetable patch and to prepare the beds now. In those parts of the country which still experience low night temperatures and frost in August, it is better to wait until next month, unless you have heated germination trays; tropical vegetables, like eggplants, tomatoes and peppers will not germinate unless the soil temperature is sufficiently high.

Seed potatoes are planted out in August and September; for harvesting in December. New potatoes are harvested much earlier. If space is limited, grow them in potato sacks or dustbins. Jerusalem artichokes can still be lifted and divided and globe artichokes can be propagated from suckers (Read last month’s article).

Peas, including sugar snap peas thrive in cooler weather, but although the plants are frost hardy the flowers aren’t, so in very cold regions they are generally planted in July or August to ensure that they flower once the danger of frost is past. Seeds can be planted directly into the garden, or into containers; low-growing varieties that don't require staking are ideal for containers and small vegetable gardens. Seedlings germinate within a week or two and grow quickly, so in 2 to 3 months you will be able to start harvesting.

With the large variety of vegetables available for summer, a common mistake gardeners make is too sow too much; rather sow smaller batches at regular intervals to ensure crops throughout summer. Another common mistake is to sow vegetables that your family does not use in large quantities, so select your varieties carefully. Look out for summer salad ingredients like celery, cucumber, peppers, lettuce, spring onions, radish and tomato, and of course, herbs like parsley, chives, basil, mint and coriander. Not forgetting those delicious home grown carrots, runner and bush beans, beetroot, eggplant, leeks, peas, parsnip, pumpkin, spinach, squash, turnip; and summer varieties of onions, broccoli, cabbage and cauliflower. If you have space for something sweet, try Cape gooseberries, rhubarb, strawberries, melon and watermelon.

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 fertilisers per square metre.  Rake the bed level, water well and allow the bed to lie for at least a week before sowing seed; 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.  Agricultural 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.

Find everything you need know about growing your favourite summer vegetables in my e-book “Growing Vegetables in South Africa” Click here to find out more.

Prepare a small herb garden for summer, preferably as close to the kitchen as possible, or alternatively, plant them between the rows in the vegetable garden to help keep your crops healthy and pest-free. Start with herbs you are familiar with and use regularly in the kitchen, you can always expand your collection later. Visit your local garden centre to see what is available seasonally. Overcrowded clumps of established herbs can be lifted and divided this month; prune them back before replanting into composted soil.

Find all your favourite herbs in our herb section.
 
Fruit trees like peaches, apricots, plums, nectarines, pears and apples will be coming into bloom 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 organic 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 in well. In the warmer summer rainfall regions it is time to sow Cape gooseberries.

Argyranthemum 'Summer Melody'Argyranthemum 'Summer Melody'Winter rainfall regions (Mediterranean)

The northwest winds may still howling, but take heart because spring is on the way, heralding the most spectacular display in the floral kingdom of the Cape. Daisies thrive in these regions; and now is the time to plant them out, try Margeurite Daisy (Argyranthemum), arctotis and osteospermum.  If heavy rainfall has compacted the soil in your garden beds, once the soil has dried out somewhat, you can lightly loosen the surface before mulching generously with compost and fertilising with 2:3:2. Check you irrigation system and make any repairs before summer.

Finish your pruning by the middle of August, but don’t prune your spring flowering shrubs and roses.  Fuchsias are pruned in late August or early September, and a general rule is to cut back by two thirds and removing dead, weak stems. Do not prune your bougainvillea until the end of November but feed with 2:3:4 or 2:3:2 this month.

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 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.

As soon as the soil dries out enough, prepare your beds for sowing and planting out summer flowering annuals; adding generous quantities of compost and a sprinkling of organic 2:3:2 and bone meal. If you have a germinator tray or a dry, protected spot outdoors you can start sowing summer flowers like ageratum, alyssum, begonia, candytuft, dianthus, delphiniums, California poppy, foxglove, godetia, gaillardia, lobelia, nicotiana, penstemon, snapdragons, viscaria and lychnis.

Early summer vegetables like eggplants, peppers and tomatoes can be started indoors in a germinator tray; and as soon as the soil is workable, start sowing bush and runner beans beetroot, carrots, lettuce, rhubarb, mealies, parsnips, peas, turnips, Swiss chard, pumpkins and squash. Not forgetting those summer varieties of cabbage, broccoli and cauliflower; and some of those fresh summer herbs like thyme, parsley, basil, coriander and rocket.

Garden PinkGarden PinkDry, semi-arid and continental regions

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. 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 as outlined in the text for all regions. Do not scarify and fertilise your established lawn until all danger of late frost is over, as the new blades are easily burnt. Remove weeds as soon as they appear and before they get a chance to set seeds.

Delay pruning your roses until the middle or even the end of August if you live in extremely cold regions.  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.

If you have a seed germinator tray or a warm, protected place, you can start sowing early summer vegetables like eggplants, peppers and tomatoes; as well as summer flowers into trays; if you don’t have a protected place wait until September because summer seeds can only be sown directly into garden beds when all danger of frost is over and the soil temperatures are warm.  

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 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 and potentilla. Also herbs like oregano, sage, rosemary and thyme should thrive.

Mixed ColeusMixed ColeusSubtropical summer rainfall regions

August can still be a very unpredictable month, so mulch all your flowerbeds to help conserve moisture and water and feed your shrubs regularly. If you have not scarified your kikuyu lawn yet do so now; Berea or Durban grass should not be scarified, just mown as usual. Check your irrigation system and make any repairs before summer. Prune your winter flowering plants and bougainvillea when they have finished blooming and lightly prune other evergreens that may need it. Do not prune spring and early summer flowering plants. Hydrangeas can be pruned if they were not pruned last summer, fuchsias can also be pruned now; a general rule is to cut back by up to two thirds and remove dead, weak stems.

Tropical fruits like figs, avocados, pineapples, paw-paws, granadilla and mangoes will 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 it in well. In these regions it is also time to sow Cape gooseberries.

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. Cuttings of begonia, coleus, salvia and New Guinea Impatiens will take root quickly as the weather warms up.

You can still make sowings of quick maturing winter veggies like oriental vegetables and lettuce; and you should get one last sowing of carrots. Plant out asparagus and sweet potatoes; bush or runner beans, beetroot, baby marrow, eggplant, cucumbers, maize, melons, peppers, patty pans, radish, rhubarb, pumpkin, squash and Swiss chard.

FuchsiaFuchsiaSummer rainfall (Temperate or Highveld Regions)

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. 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. Spring is the best time to sow lawn seed or to plant instant lawn in these regions so prepare the soil this month as outlined in the text for all regions. Do not scarify and fertilise your established lawn until all danger of late frost is over, as the new blades are easily burnt.
 
Summer vegetables and flowers can only be sown directly into garden beds when all danger of frost is over; so if you don’t have a protected place wait until September. Peas and sugar snap peas are intermediary crops which thrive in the cooler weather. In frosty regions they are sown directly into garden beds from July to August to ensure that they will bloom when the frosts are over, and can be harvested before it becomes too hot in summer. If you are lucky enough to have a seed germinator tray; or if you live in less frosty regions like Pretoria, with a warm protected spot in the garden; you can plant seed potatoes, and start sowing early summer vegetables like maize; cucumbers; eggplants; peppers and tomatoes; pumpkin and squash; as well as summer varieties of cabbage and lettuce. Runner and bush beans; beetroot, parsnips, rhubarb, radish, Swiss chard, turnips, carrots, melons and Cape gooseberries can also be sown.

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