Garden Diary: September

Bulbs and flowers

 Plant Autumn flowering bulbs such as hardy cyclamen, nerines and colchicums.

Start buying and planting your spring bulbs early, while the best selection is still available. Buy now and store tulips  in a cool dark place as they are best planted later in the year.  Follow the instructions –especially planting depths.

Continue to deadhead plants in the border and add to your compost bin.

Towards the end of the month, if the soil is not too dry, begin lifting, dividing and moving perennials. Water the divisions in well. Take the opportunity to improve the soil with compost.

It’s a good time to treat perennials weeds with systemic weed-killer. Dealing with them now will save time in the spring.

If you have gaps in the border, fill in with some of the late flowerers, like sedum, Japanese anemone and hardy fuchsias.

Sow hardy annuals like cerinthe, ammi and cornflowers for inexpensive colour next year.

 Greenhouse and Containers

Don’t forget to pot up some containers for a cheering autumn patio display.  A variety of colourful cyclamen, pansies and chrysanthemums  are among the autumn bedding now available. Add perennials like heucheras and heathers for texture.

Keep watering, feeding and deadheading plants in baskets and other containers to keep them going right through ‘til the first frosts.

This is the bumper month for harvesting tomatoes and other greenhouse crops. Continue to remove lower leaves and watch for pests. Pinch out all growing tips and any new growth in leaf axils.

Close doors and vents at night to retain heat and keep your plants cropping. Try to water in the morning so plants are not moist overnight, which can encourage mould.

As temperatures drop, start to bring tender and borderline plants like agapanthus (evergreen varieties) eucomis and bedding fuchsias under cover for the winter, include those in pots and any that need to be lifted from the border.

Start letting begonias and gloxinia dry out for the winter.

Towards the end of the month, line the greenhouse with bubble-wrap.

Trees, shrubs, and climbers

 Prune climbing roses and rambling roses once they’ve finished flowering (unless they are repeat-flowering, in which case leave them).

Keep your camellias and rhododendrons moist. They are preparing buds for next years’ flowers.

Think about installing water butts. Acid loving plants really appreciate rain water.

Prune pyracantha. Leave stems with berries where possible, not only for decoration but for hungry blackbirds.


Keep watering beans to extend cropping season.

Lift, dry and store onions.

A huge range of hardy vegetable seeds can be sown now.

Order fruit trees and bushes early in the month so that they will be available for planting this autumn.

Prune out fruited canes of summer raspberries and tie in new ones.

 Try starting a few of your favourite herbs in pots on a sunny window sill.

Cover peach trees on walls to protect from peach leaf curl which is introduced by rainfall.

Apply grease bands to fruit trees to trap the female winter moths as they climb up the trunks.


Don’t forget to net the pond to keep out falling leaves.

Don’t be too hasty to tidy up, leave seed heads to provide food for birds and some foliage for shelter for other wildlife.