September Gardening Tips

Plant out wallflowers and tulips now for a wonderful combination of spring colour.

Divide and replant perennials to ease any congested areas.

Continue sowing hardy annuals for early flowering next year – Calendula, Centaurea, Papaver rhoeas, Papaver somniferum, and Scabious can all be direct sown now. Remember to keep them weed free as they germinate.

Have a go at forcing some prepared hyacinths or amaryllis now for colour over the festive season.

Plant a layered pot of bulbs, known as a “bulb lasagne”, for your doorstep, with the largest and latest flowering bulbs at the lowest level (with at least 6in of soil/compost below the bottom of the bulb) and early flowering, smaller bulbs on top. Excellent combinations are crocus above early tulips, or try an early grape hyacinth (Muscari azurea) on top, with a late tulip (‘White Triumphator’) below. Top-dress with grit to keep the pot looking good through winter. Click here to find out more about creating a bulb lasagne.

Deadhead dahlias. Cut all the spent flowers off to the buds below them. With a little TLC, they’ll keep flowering until the first hard frost. Pick a few pristine heads as you go and arrange in small glasses or bottles on the dining table.  Don’t forget to deadhead Penstemons and Roses too, it will encourage flowers in to the autumn.

Prune climbing and rambling roses.

Keep camellias and rhododendrons well watered through the autumn, whilst they are forming thier buds.

Divide evergreen agapanthus and move them into the greenhouse for winter.

Plant pot grown fruit and ornamental trees whilst the soil is still warm and moist.

Bean and pea plants that have finished their harvest can be cut back, leaving the roots to be dug in to the soil to provide extra nitrogen for future crops.

Continue to feed tomato plants until all the fruits have finished growing and ripening. If your tomatoes refuse to ripen in miserable weather, then you could make a delicious green tomato chutney.

Sow spring onions – these will be ready to eat before the frosts get going in most parts of the country.

Do a last outside sowing of radish. With the soil still warm and moist with dew, you should be eating these in four to five weeks.

Direct sow a row of rocket. It seems late to still be sowing seed, but salad rocket does not bat an eyelid at the cold or wet. There’s no flea beetle around now either and the scourge of the slug and snail is on the decrease.

Sow all your autumn-winter picking salad leaves and herbs if not done in August.

Long-season herbs, such as chives, lovage and sorrel, should all be cut to the ground. They will be up again in a couple of weeks with fresh leaves.

Cut back the fruited canes of summer raspberries, tying in the new green canes for next year’s crop.