Biodiversity Northern Ireland

What to see and do in your garden in September

What to see

Migrant birds

For many birds, September is normally a month of mass movement and the general direction is south as large numbers of swallows, flycatchers, martins and various species of warbler head down to the Mediterranean and beyond, continuing all the way down to South Africa in the case of swallows.  Before they leave, many of these birds, even those that are predominantly insect-eating, go on a high sugar diet in order to build up fat reserves for the long flights ahead and if your garden has anything to interest them in the way of berries, species like blackcap may well pop in for a snack. 

Hoverflies

If you like garden wildlife, then you must have some ivy – ideally, plenty of it.  In late summer and early autumn, when other flowers are on their way out, those of ivy are just coming into their own and on a warm day in September can be smothered in hoverflies.  Hoverflies imitate bees and wasps, in some cases very convincingly, to provide protection from predators but are harmless to humans. They are hugely beneficial in gardens as their larvae consume aphids in large numbers. The adults feed on nectar - Hogweed, Michaelmas daisy, ox-eye daisy, guelder rose and poached egg plants are among the many plants they favour. The small flowers of Virginia creeper may also attract them.   

Painted ladies

The painted lady is a migrant butterfly from North Africa which is normally present in the UK in modest numbers. In 2009, however, it arrived in uncountable millions, from mid-May onwards, in what seems to have been the largest invasion in more than 100 years.  Unusually heavy winter rains in Morocco produced a bumper crop of the butterfly’s food plant there (thistles and mallows) and adults emerged in huge numbers and began moving north.  Most of those to be seen in Britain now will be the offspring of the original migrants: the first having stopped to breed in southern Europe.   Butterfly Conservation estimated in July that there might be as many as a billion individuals on the wing.  Although the life cycle from egg to adult takes less than 2 months, Painted Lady butterflies are relatively long-lived as adults and many will still be around in September: survivors will even try to make the reverse trip to the south. They come readily to many garden plants including, inevitably, buddleia. Enjoy the spectacle while it lasts!

What to do

The tidy test!

In September, many more plants are going to seed or looking very straggly. This, then, is a time when your commitment to gardening with wildlife in mind starts to be put to the test! Could they choose, birds would very clearly prefer gardeners to leave all seeds to ripen where they stand.  Your neighbours, on the other hand, may see your garden’s increasingly shaggy look as evidence of neglect – and wonder, too, how many of your “weeds” may transport themselves over the fence next spring.  You can always try to win them round to your own viewpoint and point out the benefits of not being obsessively tidy but sometimes a diplomatic compromise may be a wise response. In that case, at least try and leave selected seedheads undisturbed as long as possible, especially those most obviously palatable to birds.

Valuable invertebrate life also benefits from lack of disturbance and many creatures, including useful ladybirds, will hibernate in the dead hollow stems of alliums, columbines, day lilies and many other species or find refuge among the dry fronds of ferns.  Don’t, therefore, rush to remove all the apparently functionless foliage: it still has a major part to play in supporting your garden wildlife.

 You can do a lot to alleviate the suggestion of decay by introducing late summer flowering perennials.  Many garden centres may have special offers on these as the season ends and there are good bargains to be had on plants like asters, Echinaceas (fleabanes) and fuchsias, all of which are good for a variety of insects including bees.

Take part in a garden wildlife survey

If you’ve had house martins breeding on your house this year, then why not take part in the British Trust for Ornithology’s on-line survey at http://blx1.bto.org/houseMartinsSurvey/house-martins.jsp? The survey in 2008 suggested that, contrary to widespread assumptions, house martin numbers were in general no lower than in previous years although many birds were late arriving from Africa. One season’s figures, however, say little about long-term trends so the more information people relay this year and in subsequent years, the better informed we will be about how this most domestic of birds is really faring.

Other things to do

• Build a wall! Walls provide all sorts of useful spaces for a huge variety of creatures. Your wall doesn’t have to be a major structure or even function as a boundary (though it could, for example, separate a vegetable garden from an area of herbaceous perennials).  Making a wall is one way of putting all those large stones you dig up to good use.  Hibernating amphibians, ladybirds and harvestmen will use it and butterflies bask on it (if it’s in the sun).
• Make a hole in your garden fence (or wall).  Make sure it’s your boundary before you do this (or discuss it with your neighbour first) but a small hole at the base of the structure will allow freer passage of small mammals like hedgehogs (which need quite large areas in which they can forage) and mice.
• Help hedgehogs further by providing a small refuge for them. There’s no need to buy something if you’re handy with wood and nails: all you need is a small box with an entrance about 15cm (6 inches) wide. Line it the leaves or grass, make it waterproof and put in a sheltered and ideally undisturbed part of the garden. Insulate it further with leaves.  If hedgehogs are around, then the chances are that one will appreciate your efforts. If they’re not, then your hole in the wall may help to bring one in.
• You can also encourage hedgehogs by providing them with food – especially valuable as the time for their hibernation approaches and they need to put on weight.
• Divide and replant herbaceous perennials, especially those good for wildlife! Ice plant Sedum spectabile will still be in flower at the end of the month so leave this until October.
• Collect apples and freeze them. The birds may not be that interested in them now but thrushes and blackbirds and winter visitors like redwings and fieldfares will have a different view of the appeal of apples on a frozen day in January!
• Plant bulbs for next spring and summer. Alliums are great for bees and the plants seem to be slug-proof – presumably the scent of onion is a deterrent.  If you buy native bulbs like bluebell, make sure they have not been taken from the wild.  See http://www.floralocale.org/content.asp?did=23794 which will help to find a reputable supplier.
• If you have a meadow or some area of long grass, cut it this month at the latest. Watch out for young frogs, though, ideally by disturbing the grass beforehand. A broom can be useful here!