What to plant in August – vegetables, flowers and shrubs to grow this month

There is still lots of choice for what to plant in August, despite it being a quieter month in the gardener's planting calendar.

While you enjoy eating the fresh vegetables and fruits of your bumper summer harvest as you soak up the season's sunshine, you can also be planning ahead for the crops and blooms that will see you through the colder months.

So plant some of these suggestions as part of your garden ideas for a year round feast for all of the senses.

What to plant in August – vegetables to sow

'August is peak summer and the kitchen garden it is full steam ahead! We use this month to really focus on vegetables to ensure a healthy crop in the winter months,' explains Mr Mitford, kitchen gardener at Hawkstone Hall.

There are plenty of veg that can still be sown in August as part of your vegetable garden ideas so that they have time to establish before the frosts set in

1. Kohlrabi

It’s time to shine the light on the lesser known – but delicious – kohlrabi as a suggestion for what to plant in August. 

'Kohlrabi is part of the cabbage family and has a mild, sweet flavor, making it a wonderful choice to spruce up your standard vegetable plate,' says Mr Mitford.

August is the optimal time to plant both the green and the hardier purple varieties, ensuring a winter harvest of both. Kohlrabi likes a sunny area in a light and fertile spot.

'Prepare the sowing site by weeding and then make a trench about 1/2in (1cm) deep. Water along the base and then sow seeds thinly, covering with soil,' explains Mr Mitford.

'Fall-grown kohlrabi can grow larger than a tennis ball yet still stay tender. It is frost-hardy, and may last well beyond December in mild winter areas,' say the experts at West Coast Seeds.

2. Carrots

August is still the good time to plant carrots. 'Late sowing of the versatile vegetable will give you fresh produce to harvest well into the following February, when fresh vegetables are notoriously short in supply,' explains Mr Mitford.

A good tip when it comes to growing carrots is remembering to add manure to the soil before planting.

'Plant the carrots directly outside in light, fertile soil,' says Mr Mitford. 

Plant fast maturing carrot varieties, and ensure you harvest them before the ground frosts over.

3. Spring cabbage

When deciding what to plant in August, you should also be thinking ahead to crops to enjoy next year. 'Spring cabbage is delicious and tender and one of the first and finest crops to be enjoyed in the new year,' says Mr Mitford.

Cabbage takes up a lot of room – needing 17-19in (45-50cm) spacing all round, 'so ensure you have plenty of space when you are planning your kitchen garden. It’s also imperative that the seeds are not allowed to dry out and are well protected throughout the growing period,' says Mr Mitford

'Cover the spring cabbage plants with fine mesh to give protection from cabbage root fly and white butterflies,' he adds.

Flowers to plant in August

The garden is still ablaze with color in August and there are plenty of jobs to do taking cuttings, deadheading, feeding and watering.

'Much of the garden is packed with half-hardy annuals, such as cosmos, cleomes and zinnias. They are joined by a crowd of tender perennials. These are all pumping out the flowers and will provide a carnival of color into late fall along with our salvias, hydrangeas and other fall flowering plants,' explains renowned plantswoman Sarah Raven

Although fall planting doesn't start in earnest for another month or so, there are still flowers to sow if you're wondering what to plant in August.

1. Polyanthus

Polyanthus are easy to establish and they will come back year after year giving much needed early season color in containers and borders.

'Polyanthus ‘Stella Champagne’ is a soft-colored perennial polyanthus with curved petals, which I have on my doorstep in a spring pot,' explains Sarah.

To plant polyanthus, surface sow the seeds onto a tray of moist seed compost and place somewhere cool – a cold frame is ideal, suggests Sarah.

'Prick out seedlings when they are large enough to handle into 9cm pots and grow on. Acclimatize them before planting out,' she adds.

Polyanthus prefer dappled shade, so are a good companion if you are growing hellebores, or plant them as a spring container gardening idea, to reappear early every spring.

2. Cerinthe major ‘Purpurascens’ – honeywort

For flowers this fall, try a late sowing of Cerinthe major ‘Purpurascens’ early in August.

Also know as honeywort, Cerinthe major ‘Purpurascens’ with silvery leaves and purple hanging bells is one of the best annual foliage plants, says Sarah.

'This superb garden plant gently self-sows, so you should never need to buy it again after the first planting. It is also wonderful in pots, underplanting spring's tulips,' she explains.

The seeds are tough so best soaked for 12 hours and then sown direct.

'Sowing seeds as thinly as possible, or under cover into a tray. When planning a greenhouse, we also often sow cerinthe later in fall to overwinter in the greenhouse for early flowers next spring. Or sowings can be planted out in mild areas,' adds Sarah.

The flowers are attractive to many types of bees and hummingbird.

3. Nigella – love in a mist

Nigellas are a classic cottage garden plant. 

Also known as love in a mist, 'they can be directly sown into a sunny spot of the garden now in August,' says Sarah 

'Nigella ‘Persian Jewels’ variety gives a lovely soft jumble of color to any border, and the flowers dry brilliantly and are followed by pretty seedheads,' she says.

Love in a mist makes a fabulous choice if you're planning a cut flower garden, and useful as filler foliage for any vase, explains Sarah.

Flowering shrubs to plant in August

Towards the end of August as temperatures begin to cool you can start to plant flowering shrubs in many areas. This will allow them to set down roots during the cool, moist fall weather so that they are ready to burst into bloom from next spring. 

Make sure you keep your new shrubs well watered and mulch beds to preserve soil moisture. 

1. Hydrangeas

While the soil is warm and moist you can plant showy hydrangeas. With their distinctive, large flowerheads, these are popular choices for flower bed ideas.

Once you know how to grow hydrangeas you can enjoy their generous blooms in shades of pink, blue, white and green throughout summer.

Make sure you add in plenty of organic matter, such as homemade compost, to the soil before planting the hydrangea, and water it thoroughly

2. Continus – smoke bush

Known for their colorful foliage, continus are medium sized deciduous shrubs or trees that are ideal for the back of borders, adding fiery tones with varieties that bear rich wine to crimson colored leaves from spring to fall.

They are also known as smoke bush on account of their feathery flower heads which look a little like clouds of smoke.

'Cotinus can do well in any soil conditions and all are fully hardy. They can readily be propagated softwood cuttings in the summer,' explain the experts at Burncoose Nurseries.

3. Viburnum

Versatile virburnums have lovely foliage and pretty, scented flowers, so a good choice if you looking at what to plant in August in your garden borders. Many varieties also produce berries that are an attractive food source for birds and other wildlife, so they are good to include in a wildlife garden.

There are many species that are native to North America so there is bound to be a variety that is perfectly suited to the conditions in your own backyard. 

Viburnums are easy to grow, and while Viburnum tinus are among the best winter flowers, there are others that flower spring or summer, so you could choose a selection to see you through most of the year.