Gardening in August

It sounds bizarre to talk about Christmas in August, but if you want the intense fragrance of indoor hyacinths to fill your home on the big day, it’s best to buy bulbs now and plant them before the end of the month. Buy specially prepared bulbs and plant in pots or bowls filled with bulb fibre or multipurpose compost, so the tip of the bulb sits just above the surface. Water lightly then stand the pot in a cool, dark place – a garage is ideal. You can still plant hyacinths in September and October, but they may not flower until after New Year.

Wasps can damage ripe fruit in late summer and are a nuisance when you’re dining alfresco. Setting up traps can divert wasps away from outdoor living areas, reducing the risk of a painful sting. While garden centres have off-the-shelf wasp traps, it’s easy to make your own.

DIY Wasp Trap

• Take an empty jam jar, half fill it with water and mix in a couple of teaspoons of jam. 
• Cover the top of the jar with paper, secured with an elastic band, and punch a pencil-sized hole in the paper to allow wasps to enter. 
• Place where wasps are a nuisance and they’ll be drawn into the trap by the smell of the sweet, fermenting liquid.

When lilies have finished flowering, dead-head by trimming back to just above a pair of leaves. This prevents plants from producing seed, which can lead to a lacklustre display the following year.

To ensure an abundance of buds next season, ericaceous plants such as rhododendrons and azaleas need lots of water – do not let them dry out.

Wisteria benefits from pruning after flowering; use secateurs to cut back side-shoots from the main branch network, reducing whippy growth to 20cm from its base, or five leaves from the main stem.

When bulbs have reached a mature size and foliage starts to turn yellow and keel over, it’s time to lift onions.

• Use a garden fork to carefully ease bulbs from the soil and leave them outdoors in full sun, ideally on a rack, to allow the crop to ripen. 
• Before storing, check the bulbs and discard any showing damage, then place the crop in a cool, dry outbuilding such as a garage. 

While you’re on the veg patch, keep picking beans when they’re young and tender, and harvest second-early potatoes, courgettes, tomatoes and lettuce.

Stake tall brassicas such as Brussels sprouts, to prevent heavy plants from toppling in the wind.

Once lavender has finished flowering it will benefit from a light summer prune to clip away spent flower heads. This seasonal trim helps to keep plants compact and prevent unsightly, leggy growth. When cutting back straggly plants using shears, make sure there’s still new growth below the point at which you chop. If you prune too hard, cutting down to old wood, Mediterranean plants such as lavender can be reluctant to regrow and can die.

Aphids are a menace in August, infesting stems and leaves of garden favourites such as nasturtiums, dahlias and beans. Left unchecked, these sap-sucking insects can drain the life from plants and even spread plant viruses, while their sticky honeydew creates an unsightly mess. Organic solutions include blasting bugs from leaves and stems using a hosepipe (mildly effective) or using organic sprays, which are often based on sticky, fatty substances that block aphids’ ability to breathe and feed. Chemical bug killers offer effective control, with systemic sprays, which are absorbed by plants, providing long-lasting protection.

Towards the end of the month, sweetcorn cobs will have swollen rapidly on plants, but how do you tell when they’re ready to harvest?

Once the tassles have turned brown, there’s an easy test to see if cobs are ripe: peel back the husk and use your fingernail to pierce a kernel of corn. If the liquid that bursts out is clear, the cob isn’t ready and needs to remain on the plant for longer. However, if a milky solution emerges, the cob is at its peak. To harvest, twist the cob and pull it from the stem.

If frequently used areas of lawn are sparse and patchy – routes that lead to sheds and greenhouses are typical examples – installing stepping stones can reduce wear and tear and prevent muddy patches come autumn.

• Arrange stepping stones on the lawn where you want them to sit, then use a spade to cut around the slabs. 
• Now move the slab aside and cut out the shape, so that the stepping stone will sit just below the level of the lawn to prevent your mower’s blades from striking the slab. 
• Spread a level layer of sharp sand over the base of the hole before placing the stepping stone in position.

If you’re planning to sow a new lawn in September or October, then August is the best time to prepare the seedbed.

Choose a cooler day and dig the area, removing stones, debris and traces of weeds (including weed roots). If perennial weeds are a problem, spray with weedkiller in advance of digging, letting foliage die down before removal. Taking action now allows time for further weed treatment if regrowth is a problem.

Digging, weeding and incorporating well-rotted organic matter into seedbeds, ahead of sowing grass seed in autumn, allows time for the soil to settle – perfect if you want to achieve a level lawn.

Get more maintenance tips for a lush green lawn >

All summer we’re busy adding garden rubbish to compost bins, but the process where green waste breaks down into crumbly, nutrient-rich matter can grind to a halt if heaps become bone dry during hot weather. To keep the composting process running efficiently, use a garden fork to turn the contents, and add water to make sure that everything continues to rot. Keeping lids on compost bins will help to reduce moisture loss during hot spells.

Learn more about proper composting here >

Roses remain a top choice for owners of both cottage gardens and modern plots because they’re easy to grow (in fact, it’s difficult to kill them), while many are perfumed and will fill the air with fragrance. Plants can flower from early summer late into autumn (many repeat-flower well if regularly dead-headed) and there are thousands to suit every garden situation, from patio roses to climbers, ramblers to ground cover, as well as roses that thrive in pots and planters. You’ll be spoilt for choice!

Two types of roses can baffle gardeners who are unfamiliar with the terminology. The first is hybrid tea – roses that usually bear flowers on single stems. They create instant impact when planted en-masse in rose borders, as opposed to mixed planting, and are a popular choice for front gardens, formal designs and narrow borders. Some are very fragrant while others have no perfume, so check the label before buying.

Another term you’re likely to encounter is the floribunda rose. Floribundas are smothered with flowers, borne in large clusters, and are a popular choice for mixed borders. Modern varieties are tough, hardy and can offer superior disease-resistance.

Roses are sold in two forms: containerised or bare-root plants. If you’re shopping in August, garden centres will offer roses in containers. They are the slightly more expensive option, but have the benefit of being able to be planted all year-round (apart from during drought or if soil is waterlogged or frozen). Field-grown bare-root roses, sold in a dormant state, are cheaper, but you’ll have to wait until autumn, because the bare-root planting season runs from November to March.

Where do roses grow best?

Roses love moist but well-drained soil, thriving in sites where plants can bask in sunlight for at least half of the day. If you’re planting into a container, choose a big pot (roses have deep roots) with good drainage and fill with John Innes No.3 compost. Keep garden plants well-watered while they get going. Feed established border plants with a general purpose feed or rose fertiliser in summer after plants have displayed their first flush of flowers, and again the following spring before plants start to bloom. Roses grown in plant pots will need feeding at least once a month during the growing season.

Watch out for black spot, a common fungal disease that blights foliage, but can be controlled using readily available sprays. And tackle infestations of aphids promptly using an organic bug killer. Unsightly suckers (pale shoots) can spring up from the roots – dig down and pull suckers away (don’t snip them off or it encourages these rogue shoots to re-grow).

One final tip: try the scented rose ‘Belle de Jour’ -  capable of flowering from June to October, this disease-resistant floribunda is perfect for plant pots and borders and its flowers emit a vanilla and apricot fragrance.

August is all about sowing and planting speedy salad leaves and veg that’ll crop later in the season, and keep supplies of fresh produce going. Salad leaf mixes, widely available from seed suppliers, are ideal for sowing in pots until the end of August, while rocket leaves are a popular choice for sowing now for infusing late-season salads with its spicy, peppery flavour. Baby spinach leaves are perfect for getting under way now, too.

Radish can also be sown in August and September – it’s one of the easiest and quickest crops to grow from seed, with gardeners pulling fresh roots in as little as a month after sowing (crops will benefit from a little light shade if conditions remain hot during August).

If you have empty space on the vegetable plot, sow the F1 hybrid cabbage ‘Winter Jewel’ until the end of August. It’s hardy even in harsh winters, with superb flavour and excellent resistance to bolting. As long as cabbages are netted to protect from hungry pigeons, crops will be ready to harvest in April and May.

These architectural succulent wonders may be native to North Africa and the Canaries, but they love to grace hot, sunny positions in the UK during the warmer months – and are a popular choice for coastal gardens, courtyards and sub-tropical planting schemes with their near black, shiny rosettes.

For a classic Mediterranean appearance, grow in terracotta pots filled with free-draining, loam-based compost and water sparingly using rainwater collected from water butts. The advantage to growing in plant pots is that they can be brought indoors before temperatures tumble in autumn. Aeonium is an evergreen perennial and can survive outdoors year-round in sheltered microclimates of the South West.  However, it dislikes temperatures lower than 5°C and needs to be overwintered in a frost-free conservatory or greenhouse.