August tasks in the garden

August tasks in the garden


The weather looks to continue in this unsettled vein until further into the month when it may become a bit more settled with temperatures likely to be above average especially in the south & southeast.  Keep watering & feeding your plants especially in containers & hanging baskets as the mass of flowers form a canopy that the rain finds hard to penetrate. Keep an eye out for slugs & snails around your plants & vegetables & keep on top of weeds which will also be taking advantage of the good growing conditions.

We will soon be entering the ideal months for planting – spring bulbs will be in the garden centre this month & are best bought when they are fresh in. Try to recall any gaps you had, or look at any photos you took whilst your bulbs were in flower last spring then plan next year’s display. If you can’t plant your bulbs immediately store them in a cool, dry place away from direct sunlight & try to plant at least 6 weeks before you expect the first frost. This will allow them to develop a good root system but bulbs will do their best to grow no matter when you plant them.

It is also a great opportunity to plan for a new look autumn border as the garden centre will be packed with tried & tested perennials, shrubs & trees plus new varieties too. Look for plants with a long flowering period and those that have two or more seasons of interest with flowers, fruit, colourful stems or interesting foliage. Choose plants with different foliage colours and shapes whilst using winter bedding plants to increase the season's interest, and bulbs for extra splashes of colour. Keep newly planted specimens well watered especially in dry weather.

Planting & Sowing

Clematis Guernsey Flute
Clematis Guernsey Flute
  • August is a good month for taking cuttings but an alternative with some plants is to layer them. Plants such as clematis will root into the soil if you take a young shoot & peg it down to root. Keep watered & wait until it is well established then cut away from the parent. Other plants such as rhododendrons or carnations may need a small cut in the underneath part of the stem to stimulate rooting before burying that part of the stem in the soil & pegging it down.
  • Cyclamen can be started into growth by watering this month after their summer rest. Freesia corms can also be planted, plunge pots outside for six weeks before bringing inside to flower in winter.
  • August is the best time to take cuttings from half-hardy bedding plants such as fuchsias, pelargoniums, marguerites and trailing petunias. Also from woody herbs like rosemary & bay plus tender perennials such as osteospermum and those not reliably hardy such as Penstemon. Once done, cover the pots with a polythene bag or with a propagator lid and place somewhere warm and sheltered but out of strong, direct sunlight. Don't forget to pick up everything you need for taking successful cuttings including pots, compost, dibbers, rooting hormone, labels and propagator lids.
  • You may plant Globe Artichokes in the vegetable plot but you can grow them in the flower borders as a very attractive plant with large silvery leaves. Do not let the heads form if they are in the first year, just cut them off. When they come in the second year remove them just before those fleshy leaves form the flowers, you will get two flushes.
  • If your garden's starting to look a bit jaded, inject some autumn colour with containers. Plant them up yourself with favourites such as pansies, evergreen shrubs such as euonymus, and under planted with spring-flowering bulbs. Or make it really easy by taking home our ready-planted containers.
  • If you have propagated strawberry plants from runners they can be planted out now into a prepared bed.
  • Start planting up some spring bulbs. We have lots in store to choose from, including favourites such as daffodils and crocuses, and something rather grander, such as crown imperials. For colour now, add evergreen shrubs such as rosemary and euonymus, winter-flowering pansies and primroses to give you interest through autumn and winter.

Pruning

apples
  • Summer prune apple & pear trees that are trained as cordons & espaliers & prune wood that has fruited on fan-trained cherries & plums.
  • Deadhead lilies to stop the plant putting energy into seed production thereby ensuring better flowering next year.
  • Deadhead Dahlias to keep them flowering.
  • Trim lavender plants when they have finished flowering to remove the old flower heads and encourage new shoots to produce a bushy plant.
  • Cut back herbs to stimulate fresh tasty growth before the first frosts.
  • Prune raspberry canes to ground level after they have finished summer fruiting.
  • You can prune fast-growing hedges such as privet and leylandii hedges again in August. Do not do it later in the year. The shoots that grow on the hedge after pruning need to have plenty of time to ripen before winter comes.
  • Wisteria can be pruned now. Remove long whippy new shoots to five or six buds from the main stem.
  • The flowers on some plants have already finished flowering. If you ‘dead head' them (remove the dead flowers regularly), it stops the plant putting its energy into setting seeds and promotes more flowers. On some varieties such as lupin, delphinium, geum, alyssum and alchemilla a second flowering can then happen in favourable conditions. This means that you can enjoy scent and colour in your garden even longer. After pruning, give the plants a quick pick-me-up by watering on a high potash feed.

Maintenance

Rhododendron Nancy Evens

Rhododendron Nancy Evens

  • Rhododendrons, camellias and azaleas will be setting their flower buds for next year, so it's important that they never go short of water at this time of year or the flower buds may fail next spring. Feeding will also produce more and better flowers. Mulching with bark or similar products will help maintain soil moisture levels and insulate the roots from damaging high temperatures.
  • Keep your pond or water feature topped up with water, collect rainwater as this has fewer nutrients in it than tap water. It is also a good time to remove pond weed from ponds before it starts to break down releasing more nutrients into the water.
  • If you enjoy growing plants from seed & saving money at the same time, why not collect seeds from your own garden. Many plants are bearing ripe seeds now, such as campanula, mullein, primula and maiden pink. Choose a time when the weather is dry to collect your seeds then dry them and store them in labelled paper bags in a dry cool spot. Make it a family activity, you can even swap seeds with friends & neighbours to increase your garden stocks & next year you can have the fun of planting them with the kids.
  • Pests and diseases thrive in hot weather, so check plants regularly for tell-tale signs. Mildews and red spider mite are always worse in warm, dry conditions and these can soon get out of control. Earwigs eat the leaves and flower buds on plants like clematis, dahlias and chrysanthemums, and even slugs and snails can be on the prowl at this time of year.
  • Clumps of Bearded Iris can be split & replanted now, giving them time to establish their roots & form flower buds before the cold autumn weather arrives.
  • If you are plagued by difficult to eradicate perennial weeds like ground elder, nettles & brambles then spraying with a glyphosate-based weedkiller is probably the only solution. August is a good month for spraying as the plants have plenty of leaf growth to spray. Carry this out when the forecast is for dry weather & on a still day so that the spray doesn’t drift onto other plants.
  • Use boiling water as an effective weedkiller on paving & patios.
  • Make sure your plants produce a display to be proud of by giving them just the right amount of water they need. Well-established plants may not need regular watering but newly planted ones, bedding plants and plants in containers will. Continue feeding container plants with a high potassium feed to keep them flowering.
  • Remember to check roses regularly for pests, blackspot and other diseases. Spray if necessary with a recommended fungicide and/or insecticide. If your garden is in need of some flower power, roses are the perfect solution. We have plenty of quality potted roses in stock.
pumpkin
  • A liquid feed for your pumpkins will help as well as water; they have a long time to grow yet in readiness for Halloween.
  • Tomatoes need regular watering and feeding so don't let them dry out or they will get blossom end rot. Harvest as they ripen. It is unlikely that there will be enough time to ripen more tomatoes on outdoor plants before the weather gets worse so stop them after four trusses have set.
  • Move house plants such as Cymbidium outside during warm weather. Place in a shady, sheltered position & don’t forget to water.
  • As vine weevil beetles tend to lay eggs in late summer and early autumn it pays to protect vulnerable plants in pots - such as begonias, fuchsias, cyclamen and sedums - with Bio Provado Vine Weevil Killer. A wide range of pests can be controlled by spraying with Ultimate Bug Killer.
  • Move potted plants to shaded areas if you are going on holiday & stand on wet gravel to keep them moist.
  • Harvest onions, wait until the foliage starts to yellow slightly and the tops fold over. Lift from the ground and if the weather is dry, lay out somewhere in a sunny position. It should take a couple of weeks to ripen the onion bulbs in the sun, store good ones and any damaged ones use them straight away. How about stringing them together like the French do or just hang them up in some old tights.
  • The harvesting season is now in full swing now, so make sure you pick crops that are ready. Leave them too long and they'll lose flavour and tenderness. Now's a good time to sow winter varieties of spinach and main crop turnips, also endive, radish and spring cabbage for next year.
  • Having spent lots of time and effort growing your fruit and veg to perfection, protect it with fleece or small-mesh plastic netting - or, if you have a large area, put up a fruit cage.
  • Courgettes & Marrow plants are now starting to reward us with a bountiful supply of fruits. Courgettes come in all different colours and shapes today. Easy to grow and great to eat it is important to keep cutting the Courgettes when they are tender, just four to five inches long. If you let them grow longer they will stop producing. If you are growing Bush Marrows let them develop and check they are firm before cutting.
  • Harvest second early potatoes this month if the weather is wet to avoid slug damage.
  • Keep vegetable crops well watered this month, otherwise Spinach, Lettuce and Beetroot will bolt and go to seed. Beans also need regular amounts of water to keep them cropping, late sown Runner beans, if looked after, will crop all the way through to those early frosts.
  • Harvest French & runner beans, beetroot, carrots, broccoli, courgettes, peas & early Potatoes.
  • Watch out also for aphids on your peppers and aubergines and spray.

Lawn Care

  • If you have a flowering meadow that has finished flowering you can mow it now.
  • If the grass is growing well, the blades remain succulent and the lawn is easy to mow. You can now give lawn feed one more time. After this, only give special nitrogen-free autumn fertiliser. The grass must be able to ripen before winter in order to be more frost-resistant.
  • September is the best time to sow a new lawn or lay turf, but it pays to prepare the area now. To beat perennial weeds, spray with a weedkiller containing glyphosate. Once the turf has been removed, work over the soil to a depth of 9" with a fork and spade, removing weed roots and large stones, and incorporating compost or composted bark. Rake and level the soil, walk over it to settle it, rake again and then leave it bare to allow weed seeds to germinate. These can be sprayed or hoed off ready for sowing or turfing next month.

Profile Image Angela Slater

Angela Slater

Daughter of a farmer and market gardener so have always had a connection with the outdoors, whether it was keeping animals or producing fruit, vegetables and cut flowers. Along with my work at Hayes Garden World I also have a smallholding, mainly breeding rare breed pigs. I gained an HND and BSc in Conservation and Environmental Land Management, as a result I am an ardent environmentalist and have a keen interest in environmentally friendly gardening. In my time at Hayes I worked for several years in the Outdoor Plant and Houseplant areas.