Any kind of elevated garden is a bonus for wildlife, especially in towns and cities where natural habitats are so scarce. Imagine how much more wildlife-friendly space there would be if every building had a roof garden! From a few pots or hanging baskets on a tiny balcony, to extensively planted roof terraces, to whole, living, green roofs - opportunities for providing extra wildlife environments in the air are abundant.

In Your Garden

Planning

A few necessities first before you start planning your roof garden:

  • It is very important to check what sort of weight it can support as many flat roofs are not designed to be load-bearing.
  • The surface needs to be waterproof and robust enough to withstand foot traffic; timber decking or another lightweight surface may be needed to enable you to walk on it.
  • Dependent on the degree of use/construction, it’s possible that you may also need planning permission.

Since most roof gardens are exposed to the elements, consider erecting a trellis or screen if practical. This can support climbers which will provide some protection from strong, drying winds. Container-planted bamboo will also achieve the same effect.

Irrigation is important, especially as containers dry out even quicker in rooftop conditions. A water supply is useful and for larger areas, an automated system may be helpful. It’s also possible to buy special containers with built-in water reservoirs which reduce the need for daily irrigation.

If you have unused space, why not lay a green roof? A mat of low growing plants like sedums completely covers the roof and provides not only a brilliant wildlife habitat, but also insulates the room below and helps reduce flash flooding by absorbing rainwater which would normally run off the roof.

Most wildlife environments can exist in miniature on a roof. Try some of the other habitats on this website, but scaled down: A wildflower lawn in a box, or a small pond, perhaps even a compost heap. Just bear in mind weight restrictions and possible watering issues.

Establishing

Use lightweight, robust planters to keep the load to a minimum and distribute the weight sensibly by placing them next to load-bearing walls or above load-bearing joists or beams. Keep them as light as possible by backfilling excess depth with polystyrene or foam pieces and mix compost with perlite or hydroleca to lessen the load and also help retain moisture.

The roof garden can be a harsh place for plants, so choose tough, hardy varieties that will cope more easily with the conditions. Species that grow naturally in dry, coastal or mountain environments will be best suited.

If you have the perfect site for a living roof, it is possible to make your own fairly cheaply, on top of a shed, for instance; but for larger roofs it may be necessary to seek professional help.

Read more

Download the living roofs leaflet

Maintenance

The biggest task is making sure plants in containers are well-watered – this means every day for most of the year.

As with a ground level garden, try to delay the autumn clear-up until spring to provide a winter larder and places to shelter for wildlife.

A living green roof can require little maintenance, which means even less disturbance for the wild visitors!

Read more

Read the RHS green roofs advice profile

Top tips

Make sure pots with large plants are firmly anchored to prevent them being blown over.

To make a mini-creature hotel, drill holes all over a bucket or plastic container, put in some small logs vertically, then backfill with a mixture of three parts wood chips (ideally hardwood) and one part soil or peat-free compost and placed in an undisturbed corner behind other pots.