Five tips for a rooftop oasis

With apartment living on the increase in Australia, landscape design expert Matt Leacy from Landart explains how traditional backyard features can be transported to the roof, cost-effectively and sustainably.

Inner-city living is on the rise for Australian families, with the most recent data from the Australian Bureau of Statistics showing that families with children now make up an unprecedented 25 per cent of the nation’s total apartment population. But just because

you live in an apartment without a backyard, it doesn’t mean you have to give up all of the advantages that come with a domestic garden space.

You can maximise the land available and try to include a garden everywhere, even over structures, and create a green rooftop oasis to benefit not only health, lifestyle and property value, but also the environment.

Due diligence

Before getting too deep into the process of planning your rooftop garden, it’s best to first tick off the basics. That means engaging a structural engineer to check that the roof is properly intact and suitable for the type of rooftop space you’re planning.

This is particularly important for large-scale installations, especially if you’re considering big planters and additional features such as furnishings, kitchens and overhead structures, which can all be quite load intensive on the roof. Water and soil on their own are very weighty, so there may be only so much you can do.

A structural engineer will check the roof and advise on what can be done to convert it, and to make it waterproof and suitable for proper drainage, as well as advising on the weight loads the roof is able to support.

It is also essential to check with your local council to make sure that your garden plans are compliant with state and local legislation and regulations, and to gain approvals if necessary. In most suburbs, a green roof will require the lodgement of a development application.

What to plant

Just like you would if planning a backyard, think about the style you want your green roof to have, as well as your intended uses for it. Considering these factors from the outset will help you plan and execute your rooftop haven much more effectively. If you’re unsure or low on inspiration, it might be worth getting a professional landscape designer in to do the job.

Many roofs need to contend with extreme weather conditions year round – blistering heat in summer, and lots of rain and wind in the cooler months. As such, you’ll ideally want to work with plant species that are hardy and weather resistant, as well as suitable in size for the rooftop space. And if the rooftop is difficult to access, you’re best to choose plants that require minimum maintenance.

Plants that flourish in containers are often best for growing in artificial spaces like rooftops. Succulents, grasses and coastal species such as cassurina glauca and carpobrotus are great groundcovers and spillover plants. Pennisetum, lomandra and poa look amazing as ornamental grasses, and will also work to soften the overall look of the space.

Ball-shaped and architectural plants can also help lift a rooftop space. Some great low-maintenance options include succulents such as agave, kalanchoe and crassula. These varieties can also handle dry conditions, and have limited root systems, so they can survive in shallow soil.

If you’ve got good rooftop access, you might consider growing a range of organic vegetables and herbs – you’ll be able to switch them up depending on what’s in season. For easy-to-grow vegetables, consider the likes of kale, cherry tomatoes, iceberg lettuce, snow peas, spinach and zucchini. For herbs, I recommend parsley, rosemary, thyme, oregano and mint.

Consider artificial turf

Planting traditional grass lawn on a rooftop can be an expensive process, and will require quite a bit of maintenance over the long run, especially in the roof is highly exposed without much natural shade. A good alternative to the real thing can be AstroTurf, bringing with it a comparable look and feel to natural grass, but with far less watering and maintenance requirements.

You also won’t need to cut the grass, and you can let pets and little ones play on it without bringing dirt, mud and grass back into the home. If you want to make it really fun, you might even consider installing a little putting green in the AstroTurf.

Having said all of that, if you can keep your grass real, then it’s always my first choice.

Maintenance requirements

Maintenance requirements for a green roof will vary depending on its type and size, as well as weather conditions and the plant varieties growing on it. There are similarities with ground-level gardening. You’ll need to weed unwanted plants – and it’s important to fertilise at least once a year because rooftop gardens get fewer natural nutrients than ground-based gardens.

In terms of watering, it will again depend partly on how much rain you get. You don’t want to overdo it as water is very heavy on the roof, but you also need to account for the fact that rooftop gardens are generally more exposed to heat and sun than ground-level gardens. If, for example, you have a heatwave in summer, you’re going to need to water much more regularly.

The best approach to watering is to monitor plants regularly and adapt your watering in line with weather conditions as they change. Another good low-maintenance option is to install an irrigation system. The system can be programmed to suit the seasons, and tailored to your specific plants and how much water they need.

Rooftop features

Just like a ground-level garden, you’ll get much more use out of your green rooftop space if you introduce features to make it more comfortable and inviting.

You will need to consider the weight capacity of the roof as well as local building codes first, but there are a variety of outdoor features and design elements that can potentially be suitable for green roofs and enhance their overall appeal. These might come in the form of timber decking, paving or water features, through to dining tables, seating, outdoor kitchens and fire pits.

Wind and sun protection are also important considerations. Shade sails, retractable awnings, canopies and big market umbrellas can all be great options, and then you’ve got more permanent options like outdoor pavilions, pergolas and gazebos at the other end of the spectrum.