Get back to nature with green roofs and walls

My son recently wanted to build a skate ramp. I squashed the idea for a lot of reasons, but mainly because of the liability.

Growing up, no one seemed as concerned about liability. We all had treehouses.

By treehouse, I mean rotten boards hammered into a tree trunk with bent, rusty nails.

We'd climb until we were eye-level with the second story of the house and just hang out in the tree.

Some of the same desire for nature is making its way on top of our homes and walls.

Green roofs

Roofs partially or fully covered in vegetation are quite common in certain parts of Europe, providing excellent insulation and extending the longevity of the roof.

A green roof can reduce the temperature below the roof by as much as 12 degrees. Standard asphalt roofs can last about 20 years, but green roofs can last two or three times as long.

Chicago, Washington, D.C., and Baltimore are leading the United States in green-roof installations.

Recently, the city of Charleston, in conjunction with students from the American College of the Building Arts, took a step in that direction by constructing a green-roofed storage shed in Marion Square. It is the first municipal building in South Carolina to have a green roof utilizing pre-planted green-roof modules provided by local green-roof grower Green Roof Outfitters.

Most buildings are not constructed to handle the additional weight of a green roof and have to be reinforced to do so. Green roofs are more common on flat roofs rather than pitched roofs that would require additional engineering to prevent slippage.

Parts of Germany require green roofs on all new flat-roof construction.

We can introduce green roofs to elements of our landscape that are easy to reinforce, such as storage sheds.

For smaller projects, such as birdhouses and doghouses, construction can be as easy as a box around the perimeter with a waterproof barrier on the roof, such as a plastic or rubber liner.

Soil is typically lightweight and well-drained, consisting of 75 percent inorganic, such as expanded clay, and 25 percent topsoil and/or compost. Plan for the soil to be at 4 to 6 inches deep.

Fertilization, weeding and occasional irrigation (especially during extended drought) is necessary the first couple of years.

Afterwards, a fully established green roof is mostly maintenance-free.

Green roof plants need to be perennial, drought-tolerant and low-maintenance. Sedums are the predominate selection for extensive green roofs.

Sedums are succulents with a spreading growth habit.

They can be purchased at local garden centers or ordered online from vendors such www.simplysucculents.com. Sedums are easy to propagate by simply pinching off a branching and sticking it in the soil.

Green walls

Green walls are less common than green roofs. Occasionally, steel grids are anchored to walls to support vines.

Vines are commonly used because of their ability to rapidly spread, but other methods utilize a variety of plant material to achieve a more artistic effect.

In many cases, modular units are fastened vertically onto a structural grid that can be installed indoors or outdoors.

Commercial projects can be quite extensive, promoting cleaner air for indoor installations.

To see some amazing projects, go to gsky.com.

Closer to home, we can create small-scale green walls. Wooly pockets (www.woollypocket.com) are soft, multi-pocketed containers that can be hung on a wall.

When hung in a series, plants hang over the pocket lips and create the illusion of a green wall.

Living wall modules can be hung indoors or outdoors and appear more like a vertically framed container of plants.

Do-it-yourself kits can be purchased from websites such as Easy Green (www.eltlivingwalls.com) that have a convenient watering system. Succulent Gardens (sgplants.com) features succulent wreaths and living pictures that are quite unique for any wall inside your house.

Some of the structures are easy to build yourself and would just need succulent cuttings to plant into the living portrait.

Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback, e-mail him at tony. bertauski@tridenttech.edu.