September is generally noticeably cooler than August, and the nights are now drawing in, but there's plenty to be doing in the garden this month, including planting bulbs, scarifying and aerating lawns and taking cuttings from evergreen shrubs. Check out our full list of hints and tips below put together by our chairman and horticulturist John Richardson.
Keep dead-heading the best flowering plants to encourage new flowers and stop them from setting seed.
Crocosmias form large mounds of roots and corms over a few years; try separating them with a fork, pulling them apart, or removing the soil and untangling them with the help of a hosepipe jet.
The lawn will benefit from being scarified and aerated; remove moss. Add sharp sand or compost and re-seed worn patches. Apply autumn fertilizer at 2 oz. per sq. yd and apply a weed control.
During rainy weather, transplant Rhododendrons and Azaleas, which need moving and plant new bushes. Heel in plants newly arrived if the ground is not yet fully prepared but ensure that root balls are kept moist.
By the end of the month, slightly reduce the watering and feeding of house plants, and ensure they have plenty of light. Reduce the amount of water given to cacti.
Take cuttings of evergreen shrubs, geraniums and hydrangeas. Check that electrical installations are in good order and insulation is undamaged.
Prune weeping standard roses, which are summer flowering climbers and ramblers grown on standard rose briar stems, by removing the stems which have flowered during the year, and leave the new main stems to flower next year.
Purchase sweet pea seeds for sowing next month. Include a few of the old-fashioned varieties as these will provide fragrance.
Prepare sites for any new hedges to be planted over the winter months. Dig the hedge strip 45cm wide on either side of the centre line of the hedge. Skim off any turf or weed growth, burying it upside-down in the bottom of the trench. Remove any perennial weeds. Plant evergreen hedges until mid-October.
Prepare pots and bowls of bulbs to flower from Christmas to Easter. Use bulb fibre in containers with drainage holes and stand the container on a suitable saucer. Containers without a drainage hole can be used but extreme care must be taken not to over-water the pot.
Sow annuals such as clarkia, nemesia, antirrhinums, calendulas, and cornflowers in a cool greenhouse for a colourful display in spring and early summer. Sow in John Innes seed compost and prick out in pots of JI No 1 potting compost as soon as large enough to handle.
Keep dead-heading the best flowering plants to encourage new flowers and stop them from setting seed.
Cut off and burn any Iris leaves which have developed brown leaf spot disease since flowering.
Posted 30th Aug 9:34am
