Leaves are falling rapidly, and wind and rain are on the increase. Tender plants will need protecting from frost, gales and freezing rains. Move plants into the greenhouse or into a sheltered spot. If this is not possible wrap plants or pots in situ. Remember winter can be a tough time for birds in terms of water and food, so keep supplies well topped up.
Sowing and planting:
Lily bulbs can still be planted in pots this month. They can either be brought inside next spring to ‘force’ them into an early display or left outside to flower naturally in summer.
Plant tulip bulbs this month. Some tulips persist year to year, some perform less well and are treated as bedding and replaced every year.
Now is the last chance to plant out winter bedding. You could try wallflowers, forget-me-nots, Bellis, Primula, Viola, Pansies and other bedding plants, planting them into well- prepared ground or pots of suitable compost.
Cutting back, pruning and dividing:
Continue to cut down faded herbaceous perennials and add these to the compost heap.
Penstemons are best left as-is (except for deadheading) until the spring, when they can be cut back further. In mild areas they can carry on flowering well into the late autumn and early winter. The old faded stems will help to protect the crowns from cold. Mulching over the crowns in colder areas will also help.
Ornamental grasses and bamboos can be cut back and tidied up at this time of year.
It is still a good time to lift and divide overgrown clumps of herbaceous perennials.
Lift and store dahlias, cannas and tuberous bedding begonias that have been hit by the first frosts.
Root cuttings can be taken now and throughout the winter. Papaver (perennial poppies), Verbascum (mullein) and Phlox are suitable examples.
Rake fallen leaves off lawns before they block out light and moisture from the grass.
Grass will continue to grow in temperatures above 5°C (41°F), so if the weather remains mild it may be necessary to trim the lawn with a mower. Ensure the cut is 3-5mm higher than in summer to prevent turf stress. On average, this means a cutting height of around 4cm (1.5in).
Mowing will help to deal with any annual weeds that have sprung up in new lawns sown earlier in the autumn.
If putting lawnmowers away for winter ensure they are clean and dry before storing. Also remember to drain fuel as unleaded petrol doesn’t keep and may cause problems next year when trying to start up the machines.
In mild parts of the country, you can still carry out autumn lawn care i.e. scarification, aeration top dressing and autumn feed as long as the soil isn’t waterlogged. This will improve the lawn’s performance next year. Don’t feed the lawn with left-over summer feeds. These contain too much nitrogen, which stimulates lush growth; at this time of year, lush growth will be vulnerable to diseases. Use an autumn lawn feed, which contains more potassium and phosphorous, to encourage hardiness and root growth instead. Don’t do this in frosty weather, very wet weather or snow.
Avoid walking on lawns on frosty mornings. It can damage the grass and often leads to brown footprint-shaped marks.
It is now too late to sow grass seed, but new lawns can still be laid from turf if the weather is not too cold.
Apply an autumn mulch to protect plants that are borderline hardy such as Agapanthus, Kniphofia and Phygelius. The plants’ own leaves, e.g. Kniphofia, can be tied up and used as protection for the crowns underneath.
Wet September and October weather will have made many clay soils unworkable until spring. In these cases mulching will help to improve and maintain soil structure.
Make sure that you have not forgotten any of your tender plants and bulbs – they need to be brought inside or into a heated greenhouse over the winter. Protect alpines from the wet if you have not done so already.
Hellebores rarely flower naturally by Christmas despite their common name of Christmas rose. They can be encouraged to flower a little earlier by covering them with cloches, potting them up and bringing them into a warm greenhouse, or placing them on a windowsill inside the house.
Large tubs that are at risk of cracking in the frost should be covered with bubble wrap, hessian or fleece to insulate them over the winter.
Raise patio containers onto feet or bricks to avoid them sitting in the winter wet.
Remove stakes and other supports as final late-flowering herbaceous plants die down for the winter.
Tidy up leaves from around borders. They can be added to the compost heap or placed in separate bins to make leafmould. Some leaves such as plane and sycamore are slow to break down and can delay you using your compost if you mix them into the general heap. Leafmould makes an excellent soil improver and can also be used as a seed-sowing medium.
Dig new flower beds as the weather allows. Don’t work on them when it’s very wet as walking on sodden soil can cause compaction.
In mild weather weeds will still appear. Hoe regularly to keep them in check.
Now can be a good time to dig up perennial weeds with long tap roots such as dandelions and mallow from newly cultivated areas. Clay soils in particular can be more workable in autumn as they are no longer baked hard but not yet sodden and sticky with winter wet. Mulching will help to improve the soil structure.
Order seed catalogues for next year’s bedding and perennials if not already done.
Pest and disease watch:
Watch out for downy mildew and black spot on winter pansies.
Check chrysanthemums regularly for signs of white rust.
Look out for crown rot and brown rots (sclerotinia) on died downperennials, especially if you are on a clay or poorly-drained soil.
Be aware that many diseases will overwinter in the soil or on plant debris. Antirrhinum rust and Delphinium black blotch as well as sclerotinia will lay dormant and re-infect plants when they come up the following year. It may be necessary to replant new specimens in another place if the problem is severe.
Do not feed plants this late in the season as they are no longer growing and the nutrients may be washed into rivers and streams by winter rain.
Digging the soil, especially bare patches or newly cultivated lan, will expose pest larvae and eggs to birds and frosts as well as clearing weeds and improving soil structure. Don’t leave soil uncovered for too long however, as it runs the risk of erosion and washing away of valuable nutrients. Black polythene sheeting will protect it in the absence of planting or mulch.