Sweltering August

Painted lady butterfly (Vanessa cardui)

Painted lady butterfly (Vanessa cardui), Barnes Dr Thomas G, U.S. Fish and Wildlife Service , Public Domain

The extreme heat in July has been taxing for plants but encouraging for butterflies. A once in a decade influx of painted lady butterflies is expected around now in the UK. These delicate creatures perform a 7,500 mile migration, flying at heights of up to 1 km and speeds of up to 30 mph to reach the our shores. High numbers have been seen in Europe, feeding on thistles and heading over the channel. Conservation charity Butterfly Conservation is asking for people to sit outside in a garden, park, allotment or wood and count butterflies of any species for 15 minutes. Citizen Science is a very useful tool in helping conservationists record fluctuations in species numbers and develop habitats and strategies for maintaining and increasing those species at risk. Find out more at the big butterfly count.

Sultry summer days, heat haze, parched grass or torrential storms, the high summer mix. Swallows and house martins are beginning to gather in flocks before leaving for their migration to Africa to avoid the European winter. Lammas, on the 1st of August, traditionally celebrates the grain harvest and offerings of bread to the pagan gods. Meadow plants too have ripened seeds and are ready to cut, to be left on the ground to dry until the seeds fall, then raked up and removed to reduce fertility and allow the recovery of the sward for the following year. Hedgerows and trees are full of ripening fruits, berries and nuts; autumn is approaching. In dry weather the August garden can look listless. Earlier summer plants are on the wane and those that flower into the autumn may not yet have bloomed, but there are repeat flowering plants and drought tolerant species bringing colour and interest to the fading greens of late summer.

In the garden

Mizmaze at Mount Ephraim Gardens, Hernehill (Stipa gigantea)

Mizmaze at Mount Ephraim Gardens, Hernehill (Stipa gigantea), Pam Fray, CC BY-SA

Many ornamental grasses look their best in August, their tall flowering spikes reaching up from a leafy base to form gently swaying translucent curtains. They have an architectural form that remains for most of the year, creating texture, depth and movement in a garden. In late summer the seed heads shimmer in bright light glowing gold, pink and silver in the sun. Giant feather grass (Stipa gigantea) has clumps of grey green leaves, tall stems and oat like, golden seed heads. Fountain grass (Pennisetum x avena ‘Rubrum’) with its purple tinged leaves has large, soft, bottlebrush like flowering heads of pink and gold. Moor grass (Molinea caerulea subsp. arundinacea ‘Transparent’) has ribbon like leaves, tall stems and tiny seeds creating a gauzy curtain which dances in the breeze.

Clematis ‘Etoile Violette’

Clematis ‘Etoile Violette’, Rassil, CC BY-SA

There are other late-summer perennials that bring colour to the garden in August. These include the Mediterranean species such as lavender, rosemary, oregano and hyssop that are drought tolerant and thrive in the sun. Many daisy like, prairie plants are also in flower. Vibrant sneezeweed (Helenium) with rich, warm coloured petals and contrasting rounded centres, bright Rudbeckias, many with dark centres and yellow petals that lighten up the borders and the elegant, often drooping, flowers of the coneflower (Echinacea sp). Amongst these the tall and airy purple sprays of the purple top vervain (Verbena bonariensis) and the vivid, trumpet like flowers of monbretia (Crocosmia) and the perfect, deep blue, spiny, spherical flowers of the globe thistle (Echinops). Shrubs in full bloom this month include the large, spires of the butterfly bush (Buddleja); the simple, soft, saucer like flowers of the mallow (Lavatera), and the cloudy plumes on the smoke bush (Cotinus coggygria) above its brilliant deep purple leaves. The vigorous viticella clematis group, flower from July to September, scrambling through shrubs or covering walls and trellises with their rich colours. They are native to Spain and southern Europe so love the sun. Clematis ‘Etoile Violette’ has deep purple flowers, Clematis ‘Madame Julia Correven’ with rich ruby flowers and wine red Clematis ‘Royal Velours’ all bring an abundance of colour.

Other species offer repeat flowering, so it is possible to plan for a succession of plants to flower right through the summer, providing distraction from the gaps as individuals emerge at different rates and naturally begin their annual decline.

Teasel (Dipsacus fullonum)

Teasel (Dipsacus fullonum), MPF, CC BY-SA

These late-summer flowers are essential to pollinators and other nectar seekers. Late flying butterflies such as Painted Ladies and Small Tortoiseshells, the Hummingbird Hawk moth, a day flying moth, and dusk flying moths all appreciate the provision of late nectar. Some plants such as the teasel (Dipsacus fullonum) and sunflower (Helianthus annus), have seeds ripening for birds to stock up on energy as we head toward autumn.

With long periods of drought it is still important to keep an eye out for those areas in the garden that even a hard rain may not reach. These rain shadows may be under densely canopied trees or shrubs or against walls and fences, and the plants growing in them may have missed out on any rain that is offered.

Keeping plants well irrigated is essential to their survival and also reduces powdery mildew, which is particularly aggressive with plants that have been allowed to dry out. No matter how hard and long the rains falls, containers need regular irrigation because rain is more likely to drain off the plants’ foliage than into the container and their soil can dry out very fast. Consider reusing grey water from baths or fill a bucket while waiting for the shower water to heat up to save water. And don’t forget birds and mammals, these too need access to water in dry weather.

Harvesting tree fruit

A fine pair of apples

A fine pair of apples, Colin Smith, CC BY-SA

Harvest time for apples and pears depends on the weather, location and cultivar. In general harvest for early varieties of apples and pears in Southern Britain begins at the end of July but some cultivars may not be ready for harvest until late November.

It can be difficult to check for the correct time to harvest tree fruit. Ripeness can be tested by lifting a fruit still attached to the tree and twisting, if the fruit comes away with the stem attached it is likely to be ripe. Other indications include finding numerous windfalls, the changing colour of pipes from pale yellow to brown, or a heightened colouring of the skin. Always handle fruit gently when harvesting to prevent bruising.

Storing apples and pears

In general early cultivars do not store well and need to be used soon after harvest. Mid season varieties can be stored for a few weeks, carefully contained and in a cool, dark space and late cultivars store best. For storing for a long or short period, pick over the fruit and place it in racks or trays either wrapped individually in newspaper, packed in straw or in formed cardboard liners. Fruit needs to be stored somewhere cool but not frosty such as a cellar, shed or garage. Check over fruits regularly to remove any rotting specimens that may affect a neighbour and label and separate different cultivars. Do not store fruits with strong smelling crops such as onions or garlic and do not store near potatoes that release gases that may cause the fruit to rot. Good storing varieties placed in a cool space can last for six months or more. If you have no suitable storage space the fruit can be frozen, dried, juiced and preserved or made into cider or perry.

Salvia nemorosa 'Caradonna'

Salvia nemorosa ‘Caradonna’, David Stang, CC BY-SA

Cut back repeat flowering plants

Many cottage garden plants are repeat flowering. Hardy geraniums such as ‘Rozanne’ and ‘Patricia’, delphiniums, centarea, Balkan clary (Salvia nemorosa ‘Caradonna’) and lupins can be cut back after flowering as the stems start to fade. If they are then watered well and given a good liquid feed, a second flush of leaves and flowers will emerge in late summer.

Make your own liquid fertiliser

Common comfrey (Symphytum officinale)

Common comfrey (Symphytum officinale), Rosser1954, CC BY-SA

Making your own liquid fertilizer is cheap and easy. All you need is a bucket, water and vegetable waste, weeds or high nutrient plants like nettles or comfrey. You will be using waste plant material and reducing the environmental costs of chemical fertilizers. Essentially just put the plant material in a bucket, fill the bucket with water and leave to steep for around 4 weeks. The dark liquid can become smelly so leave the bucket outside. Once it is rich and brown pour it onto your plants or crops.

Plant out gaps

Wisley Dahlia

Wisley Dahlia, Colin Smith, CC BY-SA

If there are gaps in your beds or borders, after other plants have died back you can move tender or greenhouse plants such as perlagoniums, canna lilies or dahlias out into the garden to fill them. Those that were inside should be kept in the shade for a few days to adapt to the heat and higher levels of light before being placed in the sun. Ornamental edibles can also be used. Small brassicas, cabbage, broccoli and kale, oak leaved lettuce or mustard greens can be bought cheaply and grow quickly to fill the gap and in addition provide a crop later in the year.

Mass pots of a splash of colour

If the garden is generally looking faded and dull a strong splash of colour in one area will help lift it. Mass pots and containers full of flowers to brighten the most heavily used areas. Many tender perennials and summer bedding plants are now being sold off cheaply in garden centres to make way for the new autumn stock. These cheap plants are likely to last up to November if watered, deadheaded and fed through the autumn.

Leave seedheads and hips as winter fodder for wildlife

Brown and fading seed heads, orange and red rose hips bring an autumnal feel to the garden. Many create a framework of persistent spires, pods and spikes and seed heads that can give interest well into the winter. In the past it was normal to deadhead and tidy the garden as the summer progressed but if you prefer to garden with nature, the drying stems and fruits can give a further season to your plants and provide a welcome source of food for garden creatures. The fading flowers, ornamental grasses and perennials take on tints of gold, russet and silver, transformed when back lit by the lowering sun and can be especially magical, shinning silvery white, in a frost.

Gardening tasks in August

Woody Plants

  • Trim hedges after checking for late nesting birds.
  • Prune Wisteria by cutting back the lateral and side shoots that have grown since spring to just a above the fifth or sixth set of leaves on each stem – or back to the appropriate shoot it the stem has grown to its allotted space.
  • Deadhead and summer prune those climbing and rambling roses that do not flower repeatedly and have no ornamental and edible hips.


  • Source spring flowering bulbs such as daffodils, crocus, hyacinth and allium for planting in autumn.
  • Sow hardy annuals to overwinter in beds and borders at the end of the month.
  • Prune lavender by removing old flowering spikes back into 2-3 cm of green growth whilst maintaining the form of the plant.
  • Deadhead plants such as repeat flowering roses and hardy geraniums to encourage further blooms this season.
  • Feed pots and other containers to keep them flowering.


  • Summer prune restricted fruit forms such as cordons and espaliers to allow sunlight to enhance ripening.
  • Harvest ripe apples, pears, plums, late cherries, autumn raspberries, peaches, blackcurrants and blackberries.
  • Prune summer fruiting raspberries. Cut out all this years fruited stems to the ground and tie in the new green canes.
  • Prune the side shoots of grape vines to expose the fruits to the sun.


  • Keep birdbaths full and leave out water for any mammals that may visit your garden.
  • Leave the seed heads of drying ornamentals and berries in borders, hedges and trees for wildlife.

Sustainable Practices

  • Water plants well at least once a week during periods of dry weather especially recently planted trees and shrubs. Distressed plants can recover after a thorough soaking. Container grown plants are likely to require more watering and be sure to water these so that the water just dribbles out of the bottom of the pot.
  • Mow or scythe summer flowering meadows, leave the plants to dry for a few days before collecting. The seed will fall from the plants but removing the rest keeps the soil low in fertility that is what wildflower meadow prefer. If there is any chance of hedgehogs in your meadow area first mow to knee height, check the ground and remove any hedgehogs to a safe place before the final, lower cut.
  • Keep ponds topped up with harvested rainwater. Clear dead foliage from the pond to avoid it building up to a sludge and increasing the fertility levels, this will cause algae to grow and cloud the water.
  • Collect seeds for next season. Store seeds in a cool, dry and dark place. Label the containers with the plant name and date of collection.
  • Have a general tidy of dead and damaged foliage on plants throughout the garden.
  • Keep an eye out for pest and diseases. Check for unusual scarring, stickiness, webbing, curling, lumps or discolouration on stems, leaves and flowers. Remembering to check under the leaves too. Look for the presence of insects, larvae or pupae, which appear static or in abundance. Identify if there is problem with a pest of a disease and remedy as appropriate using organic and biological methods. Bear in mind that many problems with pest and diseases can be prevented and controlled by good garden hygiene, growing and feeding practices. Pests can also provide food for birds, frogs and beneficial insects so only treat if necessary.

Relaxing reading

The Botany of Desire: A Plant’s Eye View of the World

Michael Pollan

The book imaginatively illustrates the links between human desire and domesticated plants focusing on the apple, tulips, marijuana and the potato.

Buy >

Field Guide to Urban Gardening: How to Grow Plants, No Matter Where You Live: Raised Beds • Vertical Gardening • Indoor Edibles • Balconies and Rooftops • Hydroponics

Kevin Espiritu

A guide to gardening in small urban spaces.

Buy >

We are a participant in the Amazon EU Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.co.uk. Our recommendations are independent and are in no way influenced by any advertiser or commercial initiative, but we may earn a small commission if a reader clicks through and makes a purchase. By clicking on an affiliate link, you accept that third-party cookies will be set.

Things to see, places to go

London Wildlife Festival at Walthamstow Wetlands

The London Wildlife Festival is a new and exciting urban event celebrating the conservation and culture of Britain’s natural world. To be held at Europe’s largest urban Wetlands, Walthamstow Wetlands, an amazing 211 hectare nature reserve with 10 stunning reservoirs. The weekend will be filled with fun activities for the family all inspired by nature and conservation and a diverse program packed full of talks and immersive workshops. Whether you’re a keen nature enthusiast or looking for something a little bit different this summer, there will be something for you.


9 - 11 August 2019


Walthamstow Wetlands, 2 Forest Road, London N17 9NH

Learn more >

Open garden evening with Eco-Poets

Come and enjoy the beautiful garden with a glass of wine on a summer evening, with a special visit by local eco-poets.


22 August 2019, 6pm - 8pm


South London Botanical Institute, 323 Norwood Road, London SE24 9AQ

Learn more >

Catriona Andrews


Catriona is a landscape designer and environmental educator. Her work combines naturalistic planting and sustainable practices to create spaces that are sensitive to the environment and welcoming to wildlife. She designs private gardens, community gardens and public spaces and leads courses and workshops on garden and planting design and the environment.