Your Monthly Planting Guide

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
• Blackberries
• Cape gooseberry (physalis)
• Figs
• Grapes
• Melons
• Mulberries
• Nectarines
• Peaches
• Pears (early varieties)
• Plums
• Tayberries

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. 

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 & 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 & 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.

Perennial herbs can be planted now into borders or containers: 

• Rosemary
• Thyme

The growing season of annual and herbaceous herbs can be extended by bringing them indoors:

• Basil
• Bay
• Chives
• Coriander
• Dill
• Mint
• Parsley 

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:

• Basil 
• Chives
• Coriander
• Dill
• Mint
• Oregano
• Parsley
• Tarragon

Some herbs are evergreen and will sit in the garden ready to be picked all year round:

• Rosemary
• Sage
• Thyme 

Herb & 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. 

There are plenty of bulbs which can be planted in September to give the garden a flush of colour next year:

• Alliums
• Anemone
• Bluebells
• Daffodils
• Hyacinths
• Irises
• Fritillaries
• Scillas 
• Snowdrops
• Spring-flowering Crocus

Spring bedding can be planted straight outside:

• Forget-me-nots
• Pansies & violas
• Wallflowers

Seeds of the following flowers can also be sown outside now:

• Calendula (marigolds)
• Centaurea (Cornflowers)
• Consolida
• Limnanthes (poached egg plant)
• Poppies
• Scabiosa

Flower & 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.

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.

Finishing touches:

• 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.