What to do in the garden in mid September

Hazelnuts harvest

Hazelnuts are beginning to show and will be ready to harvest at the end of the month. We have hazel hedges to make the ‘walls’ between the ‘rooms’ in the kitchen garden, and the nuts are secondary, but we do get some, in spite of the winter pruning. The summer pruning ‘brutting’ or the breaking of strong laterals by hand should be done in August. This is too untidy for us, so we prune in February when the catkins start to release their pollen, but still treat each branch as a cordon. When you order the young trees, get a mix of cobnuts and filberts to help pollination.

Greenhouse clean-up

Your greenhouse may be nearly empty of stock at this time of year and so it’s a good moment to have a thorough clean both inside and out. Depending on its structural materials, using old-fashioned soap and water is often the best and easiest way to wash down the glass and framework certainly, if you still have some large plants inside that you can’t move. For modern, aluminium frames, a pressure-washer is useful to remove any pests sheltering in the nooks and crannies. And don’t forget your benches, too, as such pests as adult vine weevils hide in the corners.

Tender perennials

For propagation, your pots and trays must be clean the same goes for the growing medium. We prefer a two-to-one mix of fine Irish moss peat and coarse grit; it’s more successful than peat-free bark composts, but if you use plug trays, you’ll use very little peat. Winter isn’t always kind to tender peren-nials, and it’s sometimes better to start with new ones every year. Take softwood cuttings of penstemons now, being sure to take only the best stems. They should be about 2in long and without any flower buds. The next stage is easiest with a mist propagator, as the moisture stops the cuttings drying out, but, otherwise, you can try putting plastic bags over the cuttings in a shady corner of your greenhouse. Osteospermums, Erigeron Charity and double blue Scabious are all worth propagating and root easily, but you should be careful to take only non-flowering, basal cuttings.

Mow the meadow

No matter the size of your garden, it can benefit from an area of wild flowers that will attract friendly insects. We have about a third of an acre the other side of the kitchen garden wall that starts flowering in the spring with cowslips and tails off about now with wild geraniums, knapweed and mallow. When the last flowers have gone, we mow, turn and dry the hay, which is then stacked for feeding to the park’s Lincoln Red cattle in October. (Turning the hay in situ shakes out most of the seeds of the wildflowers for next year’s germination.) We then top the whole area with a mower to keep the rough grass short for the remaining growing season.

Philip Maddison is head gardener of Harrington Hall, Lincolnshire (www.harringtonhallgardens.co.uk)