The urban potential of wildlife gardening

It has been estimated that 23% of the area of urban Sheffield is covered by domestic gardens (about 33 square kilometres). There are approximately 25,000 ponds, 350,000 trees, and 45,000 bird nest boxes in gardens across the city (University of Sheffield’s ‘Biodiversity in Gardens’ project).

Taken together, Sheffield’s gardens are a nature reserve on a truly massive scale and each of us can make big difference individually and collectively. We can provide wild animals with essential living quarters, places to eat, drink, rest and reproduce. Plants, fungi, ferns, lichens, algae and so on also find a welcome refuge in gardens.

Our gardens form a patchwork of green spaces and merge to form wildlife corridors where wildlife can pass between various habitats around the city.

All we need to do to help wildlife further is make sure our gardens are safe e.g. by avoiding chemicals and litter, and welcoming e.g. through appropriate planting and maintenance.

How to make pea soup from garden leaves!

As with most forms of gardening, wildlife gardening requires us to plan ahead. One task this month that could pay dividends next year is to remove fallen leaves from the pond. As leaves rot they release minerals and nutrients. Next spring you could end up with pea soup if the nutrients encourage an algal bloom.

If leaves are left year on year they also form a thick layer of detritus at the bottom of the pond. Although this smelly mud is an important micro habitat, and a small amount should always be present, in severe cases it can silt up the pond, losing depth. Then, as the pond becomes shallower, it offers fewer habitats for animals, plants and microorganisms that require different depths. A silted up small garden pond also becomes an unstable habitat, freezing solid in winter, and becoming warmer than usual in summer. A falling water level due to evaporation also becomes more serious.

Pruning, dividing and planting some wildlife-friendly plants

The native 'old man’s beard' or traveller's joy' (Clematis vitalba), as it is variously known, doesn't need pruning to encourage flowers but if it is challenging your patience you can cut it back by two-thirds this month. It is best left bushy, however, as it is a good nesting site for birds.

Ivies that are threatening to grow into undesirable places such as around windows and gutters can be pruned once flowering has finished. Go easy on them, however, as they are a favourite hibernation site for insects. Birds will nest in larger, more mature specimens and spiders and harvestmen also enjoy the shelter, as well as the plethora of insects that dwell there.

Snakeshead fritillary (Fritillaria meleagris) bulbs can be planted now. They will produce beautiful, waxy, nodding bells around April. The nectar and pollen will attract butterflies, bees & bumblebees. Between now and February is ideal for dividing lily-of-the-valley, ensuring plenty of pollen for bees in spring.

Ladybird and lacewing lodges - perennial stems and plastic bottles

With the arrival of autumn frosts the borders become littered with dry, brown perennial stems. It can be tempting for the tidy gardener to rush out and cut them down yet there is good reason to leave them. Apart from the fact they often look pretty when frost crystals form on them and glisten in the sun, they are also a winter refuge for hibernating insects. A number of these insects are great natural pest controllers in the summer months, especially aphid-eating ladybirds and lacewings.

Artificial refuges for insects can be made by cutting the ends off a plastic bottle to make a waterproof tube and stuffing this with hollow stems or bamboo. One end of each stem is usually plugged, e.g. with plasticine, to make it warmer and drier. The insect lodge is placed horizontally and out of sight in a shrub or hedge.