Your Monthly Planting Guide
Gardening in September
September is pleasantly warm enough to enjoy pottering in the garden, with the relentless heat of previous months usually behind us. The evenings arrive earlier and are slightly cooler, a sign of the changing conditions of autumn. There’s plenty to keep you active in all areas of the garden, with fruit to be harvested, bulbs to plant ready for the spring, seeds to save from spent flowers, and perennials to plant out in the borders.
What to plant and do in September?
The vegetable garden is at the height of production in September, whilst there are plenty of bulbs and flowers to plant in September too. Discover what you should be doing in your garden in September as we head into the autumn.
Courgettes (Cucurbita pepo)
Courgettes are a common summer staple in the vegetable garden.
Runner beans (Phaseolus coccineus)
Runner beans (Phaseolus coccineus) are among the easiest and most rewarding vegetables to grow.
Spring onions are a delicious addition to a whole range of dishes, from summer salads to stir-fries.
Potatoes (Solanum tuberosum)
Potatoes (Solanum tuberosum) are tubers that grow and form at the plant’s roots.
Garlic (Allium sativum)
Garlic is the base of so many delicious dishes, and growing garlic at home is now very popular.
How to grow and care for Lupins
Lupins are a traditional addition to any garden, providing colourful flowers from late spring through to mid-summer.
How to Grow French Beans
French beans are a versatile vegetable, producing attractive, long, thin pods, and creamy haricot beans. They are a...
How to grow and care for Cavolo Nero
‘Cavolo nero’ is a variety of kale, closely related to broccoli, cauliflower and cabbage.
How to grow and care for Rocket
Salad rocket, like its name, is a fast-growing salad leaf, perfect for adding a peppery spiciness to your salads.
How to grow and care for Chard
Chard, or Swiss Chard, is a delicious and beautiful plant which will bring harvests to the kitchen and colour to the...
How to grow Sorrel
Sorrel is a great substitute for spinach, with a similar texture but a sharper citrus flavour.
How to grow sugar snap peas
Sugar snap peas are a deliciously sweet, fun and quick-cropping vegetable to grow.
If you’re a strawberry fan, the many varieties of ‘Fragaria × ananassa’ are easy to grow at home.
Raspberries (Rubus idaeus)
What could be better than a bowl of sweet, freshly-picked raspberries in summer?
Eaten fresh, baked in muffins or as the star attraction in jams or desserts, blueberries are always delicious.
How to Grow Banana Plants
With their exotic and enormous foliage, banana plants add a taste of the tropics to the garden. In the UK they rarely...
How to Grow Butternut Squash
Butternut squash are a late season favourite, with attractive fruits which will keep well throughout the autumn and...
How to grow and care for peaches
What better way to round off a summer meal than with a luscious peach? Even better, a peach you’ve grown yourself!
How to grow and care for mango trees
Everyone loves mangoes, but did you know that you can grow a mango tree from a seed?
How to grow and care for cherry trees
Cherry trees are truly beautiful, with different species offering gorgeous flowers, bark, leaves, and fruit. You can...
How to grow and care for Crocosmia
Crocosmia bring flashes of bright colour and vibrance to a garden, with their graceful, delicately arching flower stalks...
How to grow and care for Ceanothus
Ceanothus is a beautiful and eye-catching perennial shrub. The vivid and prolific blooms are usually blue, but white and...
How to grow and care for garden Euphorbias
Hailing from a diverse range of habitats/regions, there’s a Euphorbia to suit you – whether you’re looking for a...
How to grow and care for Buddleia
Commonly known as the butterfly bush, Buddleia davidii is a hardy, summer flowering shrub which is very easy to grow.
How to grow and care for Bay Trees
A slow-growing and easy-to-care-for plant, the bay tree is extremely popular. The aromatic leaves are widely used in all...
How to grow and care for an Ornamental Quince
The Ornamental Quince is a small, pretty shrub with lots to offer to any garden.
How to grow and care for Asters
Asters are perennials which produce lots of colourful daisy-like flowers year after year.
How to grow and care for Dianthus
You may have heard of Carnations, Sweet Williams, and Pinks - these are all types of Dianthus.
How to grow and care for Verbena
The many different species of Verbena are great for bringing useful pollinators to the garden.
How to grow Gypsophila (Baby Breath)
Gypsophila has earned its nickname from the sweet-sour milk smell of its flowers, which resemble that of baby’s breath.
How to grow and care for Forget-Me-Not flowers
The vibrant blue flowers of Forget-Me-Nots make them a pretty choice for brightening a spring garden.
How to grow and care for Hollyhocks
Common hollyhocks are an elegant, traditional flower, perfect for a classic cottage garden.
Coriander (Coriandrum sativum)
Coriander is a must in salads and as a fragrant green addition to Indian, Thai and Chinese curries.
Chillies (Capsicum annuum)
It seems that most people now have at a few chilli pepper plants at home.
How to grow and care for peppermint plants
Peppermint is super easy to grow. The flowers attract beneficial wildlife to the garden, and peppermint plants are...
How to grow Borage
Borage, or starflower, is an easy-to-grow herb with edible flowers and leaves.
Sweetpeas (Lathyrus odoratus)
Sweetpeas (Lathyrus odoratus) are an incredibly popular summer climbing plant. They produce masses of flowers all summer...
How to grow and care for Geums
Pretty and delicate, Geums provide colour throughout the summer. They are frost tolerant, happy in a range of soil types...
How to grow and care for Honeysuckle
Evocative of summer country gardens twining around garden fences, walls or pergolas, Honeysuckles are a favourite...
How to grow and care for Helenium
Bearing bold flowers in orange, red and yellow, Heleniums are a bright and cheerful addition to the garden border.
How to grow and care for Nerines
Perfect for autumn colour, the brightly coloured Nerine is a great addition to a sun-soaked border. They can also be...
How to grow and care for Violas
The Viola is an adaptable low growing bedding plant coming in both classic and trailing varieties.
How to grow and care for Cosmos
Cosmos, also known as Mexican Aster, is a great low maintenance and long flowering annual.
How to grow and care for Snapdragons
Coming in a range of colours and sizes, Snapdragons bloom from June through to October on tall spire stems.
How to grow and care for Anemone
Anemones are a cheerful and vibrant group of plants, providing interest from early spring onwards.
How to plant a tree
A well planted tree will live for decades, providing endless benefits to the environment and wildlife.
How to grow and care for Sedums
Plants in the Sedum genus are easy to grow, produce lots of nectar for pollinators, and provide lovely autumn colour.
What vegetables to plant in September
Sowing vegetables in September will bring spring harvests and help to cover the ‘hungry gap’ between seasons:
- Spring onions
- Spring cabbage
They can all be sown as seeds, straight into prepared soil. Protect from birds with tightly secured netting.
What vegetables to harvest in September
September is the pinnacle of the vegetable growing season, with heavy quantities of veg available to the home grower:
- Broad beans
- Butternut squash
- French Beans
- Peppers (chilli)
- Peppers (sweet)
- Runner beans
- Summer cabbage
Vegetable plant maintenance in September
There is plenty to do in the vegetable patch to keep it productive throughout September:
- Broccoli, Cabbage & Cauliflower - keep netted with a fine mesh to stop cabbage white butterflies from landing and laying eggs. These turn into caterpillars which can then destroy crops.
- Brussels sprouts - earth up and firm down soil around plants, to prevent rocking in windy weather.
- Celeriac - remove horizontal leaves to expose the crown and help the root bulk up.
- Chilli peppers - keep harvesting to extend the productive season as long as possible. They can be used fresh, frozen or dried out for use over the winter.
- Cucumber - pinch out the growing tip, water and feed with tomato fertiliser.
- French & Runner beans - allow a couple of pods to dry out on each plant. Collect these and place in a paper bag until the spring when they can be sown again.
- Leeks - earth up the stems with soil to increase the length of the white stems.
- Peas - add supports to peas sown in the summer. Twigs from early autumn pruning activities are perfect for this.
- Radish - water well and pick every few days. They are quick growers, and the roots will quickly go woody and become unpalatable if left too long.
- Tomatoes - pinch out the tops of plants. Remove any growth below the lowest fruits, any leafy growth which is shading fruit, and any new flowers. This will increase air flow and help the plant to ripen the remaining fruit.
- Turnips - thin these to 8cm (3in) apart. The leafy tops of the ones which you remove can be used in the kitchen as greens - in stews and omelettes, for example.
If the hot and dry weather of the summer has continued, make sure to keep plants well-watered. This is particularly important for new seedlings, which can quickly wither without a little help.
What fruit to plant in September
Strawberries can be planted in September, either by using runners from existing plants, or buying new ones. They are easy to grow in the ground or in pots.
September is the perfect time to order new fruit trees and bushes, with the widest selection of varieties becoming available as bare-root plants. Fruit plants are perennials, and will be in your garden for years, possibly even decades, so consider what is right for you and your garden:
- The size of a mature fruit tree is determined by the rootstock it has been grown on. A reputable grower will advertise which one has been used for a particular plant. It is important to know this as a full-grown tree on ‘MM111’ rootstock can grow to 6 metres (20’) high! Apple, apricot, nectarine, peach, pears, plum and quince trees are all grafted onto specific rootstocks.
- The amount of fruit produced can be increased by planting a variety which has a nearby fruit tree from the same pollination group. Pollination groups are a widely-used way of categorising together fruit plants which flower at the same time. This maximises opportunities for insects to cross-pollinate the flowers, which will then form fruit. Apples, cherries, pears and plums are grouped in this way.
Many fruit trees can also be planted in containers. There are not so many varieties, and they will need lots of water in hot spells, when they will dry out quickly. However, they are great as feature plants in ornate planters, or if you want maximum productivity from a small space.
What fruit to harvest in September
September can provide bumper crops of homegrown fruit. Pick fruits regularly to catch them at their best:;
- Alpine strawberries
- Apples (early varieties)
- Autumn raspberries
- Cape gooseberry (physalis)
- Pears (early varieties)
If you want to keep berries for use over the winter, wash them and add to a container in the freezer. Give it a shake after an hour to keep them from sticking to each other, making it easy to take a handful whenever needed.
Fruit plant maintenance in September
Fruit trees and bushes need little maintenance in September. Do the following to keep plants healthy:
- Help grapes to ripen by removing leaves where they are shading the fruit.
- Feed citrus plants with a specialist plant food.
- Water new fruit bushes and trees if the weather is hot and dry, especially those in containers.
- Remain vigilant for pests and diseases which may attack your fruit plants.
Heavily fruit laden branches of apple and pear trees may need support. If necessary, support the branch from below with a stout stake, or by attaching strong rope from the branch to a nearby wall.
What trees and shrubs to plant in September
Autumn is the perfect time to plant perennials and shrubs. Perennials are either herbaceous, meaning that they will die back later in the year and reappear in the spring, evergreen or semi-evergreen. This means they will give interest all or most of the year round. They will live for many years, so choose plants which are right for your garden and which you find attractive. Consider:
- Conditions. How damp, dry, sunny, shaded, or sheltered is the part of the garden where the plant will grow?
- Size. How tall and wide will the plant grow?
- Leaf colour. How will the foliage change throughout the year?
- Flower colour. What colour will the flowers be? When will it flower, and will this complement other flowering plants?
- Wildlife. How does the plant help other creatures to thrive? Does it provide seed-heads, berries, nectar, shelter or other benefits to wildlife?
- Maintenance. How much attention does the plant need once it is established?
Here are a few beautiful perennials and shrubs which can be planted in September:
- Brunnera macrophylla ‘Variegata’
- Eryngium varifolium (Sea holly)
- Euonymus europaeus (Spindle)
- Hedera helix (Ivy)
- Leucanthemum (Shasta daisies)
- Ranunculus aconitifolius (White Batchelor’s buttons)
What trees and shrubs to prune in September
Late-summer flowering shrubs which are past their peak can be pruned now. This includes:
- Jasmine. Cut back stems that have flowered. This will rejuvenate the plant ready for next year.
- Lonicera (common honeysuckle). Cut back stems that have flowered by about a third.
- Rudbeckia. Cut to ground level, or just above any new green growth which has appeared near the base of the plant.
Tree and shrub maintenance in September
- Hoe around plants to keep weeds down, as these will provide competition to shrubs.
- Remove any perennial weeds such as bindweed and nettles, and drown or desiccate them before adding to a compost heap.
- Mulch plants with compost to provide nourishment and retain moisture.
- Check that a plant is growing as you would expect, and if it is not, consider whether it needs to be divided or replaced later in the year.
- Divide perennials that have finished flowering, such as daylillies, delphiniums, dianthus, dicentra, herbaceous peonies and primulas. This makes new plants for you to put in other parts of the garden, or to give away to friends, family and neighbours.
- Get ready for windier autumn weather by adding supports to plants. Stake and tie them so that they do not move significantly.
- Enjoy ornamental grasses which are turning brown, and do not prune yet as they can look spectacular at this time of year.
What herbs and spices to plant in September
Perennial herbs can be planted now into borders or containers:
The growing season of annual and herbaceous herbs can be extended by bringing them indoors:
Plant them in an attractive container if bringing into the house, and move to the windowsill or conservatory. Alternatively, a greenhouse can provide a suitable environment to keep the herbs in leaf for a little longer.
What herbs & spices to harvest in September
Herbs can be picked fresh or harvested and kept for use over the winter. Just a pinch can transform the flavour of a dish. Pick, wash, chop and freeze the following:
Some herbs are evergreen and will sit in the garden ready to be picked all year round:
Herb and spice plant maintenance in September
- Divide and replant chives to reinvigorate them.
- Cut back mint to about 5cm (2in) above ground level once it has finished flowering.
- Feed coriander and dill with an all-purpose plant food to help the plant to produce more leafy growth.
- Save seeds from basil, coriander, dill, caraway and fennel. Collect them on a dry day and leave on a warm windowsill for a week before placing in an envelope. Label the envelope with the name of the plant and the date that the seeds were harvested.
What flowers and bulbs to plant in September
There are plenty of bulbs which can be planted in September to give the garden a flush of colour next year:
- Spring-flowering Crocus
Spring bedding can be planted straight outside:
- Pansies and violas
Seeds of the following flowers can also be sown outside now:
- Calendula (marigolds)
- Centaurea (Cornflowers)
- Limnanthes (poached egg plant)
Flower and bulb maintenance in September
There are a few key maintenance tasks to continue into September to keep flowers looking good:
- Water flowers, in particular those in containers, which will dry out quickly if the weather is still hot.
- Deadhead plants, such as lilies and dahlias, to encourage new flowers.
- Remove summer bedding which is past its best to the compost heap. Prepare soil and containers ready for hardy winter and spring bedding.
- Monitor for pests and diseases, such as iris leaf spot. This is a fungal disease which looks rather unpleasant; keep plenty of air flowing around irises by removing old leaves.
Prepare for next year by doing the following:
- Save seeds from flowering plants to sow again next year. Honesty (Lunaria) and Violas produce seed pods which are very easy to identify and collect.
- Plant bulbs in lawns to create a swathe of spring colour. Use a bulb-planting tool to cut and remove a plug of turf, place the bulb in the hole, and replace the turf. An alternative is to use a sharp trowel to cut a slit in the turf and place the bulb in the bottom.
Lawn maintenance in September
Mowing your lawn in September:
- Cut the lawn every fortnight.
- Add grass clippings to the base of other plants to help retain moisture.
- Mow or rake up any fallen leaves to allow light to reach the grass. This will mean it continues to grow and breathe throughout the autumn.
Watering your lawn:
- Water the lawn if the summer heat has left it looking parched. Do this first thing in the morning or later in the evening, so that the water has a chance to soak down into the soil before evaporating in the daytime heat.
Problems to look out for:
- Look out for lawn pests and diseases, such as red thread, take-all patch, fairy rings, chafer grubs, and leatherjackets. Treat as needed.
- Brush worm casts around the lawn using an up-turned spring-tined rake or stiff brush. The casts add fertility to the grass, and although they may look unsightly, they are a sign of a healthy garden.
Rejuvenating the lawn:
- Feed the lawn with a high-potassium fertiliser to help the grass to develop strong roots.
- Aerate any well-worn patches of lawn, using a garden fork to create holes 3-4 inches deep.
- Use a top-dressing especially formulated for lawns to even out any hollows in the lawn. Do this gradually over the course of several years so as not to completely bury and kill the grass.
- Reseed areas of lawn which are bare or well worn by lightly raking the surface and sprinkling grass seed over the area. Net it to protect from birds. The seed should start to sprout within a week.
Towards the end of September is also a good time to lay new turf.
Find your local store and start growing your garden.
Find your local store and start growing your garden.