Florida Green Roof and Living Wall Plants, Salt Tolerance Lessons from Mother Nature Ferns

One of the greatest learning centers of #greenroof and #livingwall knowledge can be found on and across the buildings in any local downtown, urban core area.

Ferns growing unattended on old brick adjacent downtown ocean pier, Kevin Songer 

Every living wall and green roof designer, as well as landscape designers and botanists should carry a 'found plant' journal to record information when they come across such resilient plants as those growing in the cracks and crevices of building walls and roofs, without soil media or added irrigation.

Ferns growing unattended on old brick adjacent downtown ocean pier, Kevin Songer 

Looking back across the decades, this is how I learned what I did concerning shallow root growing systems, nature irrigation and plants suitable for hot, windy, salty environs.

Ferns growing unattended on old brick adjacent downtown ocean pier, Kevin Songer 

These ferns are growing on a wall adjacent the downtown pier in Pensacola, exposed to desiccating winds and a barrage of salty mist.  And they seem to be thriving.

Always keep an eye out for those free lessons from Mother Nature about living wall and green roof plants!

Salinity Tolerance of Plants (Reference Link)

Here is a link for a very useful plant salinity tolerance chart I find useful in coastal green roof design, published by The WateReuse Foundation.

The WateReuse Foundation's helpful Salinity Tolerance Chart for Plants.

Beat Your Florida Green Roof Wind Impacts With Rich Coastal Biodiversity

The very best way to understand how your coastal green roof (and for that matter any green roof) will preform is to visit the site as often as possible before the plants are installed.

I always say 'wind is the biggest killer of green roof plants' and there have been many posts about wind impacts in this blog over the years, including;

• Designing a Florida Green Roof to Withstand Desiccating Winds (April 2014)
• Green Roof Dead Zones - Why Wind Breaks are Necessary (February 2011)
• Brown Green Roofs, Green Roof Forensics (July 2011)
• and so many more

Wind and light are two of the most important green roof design variables.  We at MetroVerde consider light and wind to be the two primary green roof design variables to take into consideration when developing ideas for a green roof.

The very best way to know whether or not wind is going to impact your project is to walk the site as often as possible, in the morning and throughout the day and in the evening.   Wind impacts fluctuate depending on a number of factors, including time of day.

Sunlight, air temperature and gradients and many other variables can influence air movement.

My teen daughter and I took a walk along the Atlantic coastal beach this morning and the and was blowing!  The pier's flag was standing straight out and whipping back and forth and we estimated the sped to be about 15 meter's per second - almost 35 miles per hour.

Most any plants are going to suffer in winds that fast and many broad leaf plants will quickly desiccate out and possibly die, especially as salt deposition from the ocean spray coats the leaves, stems and flowers.

Over the years we have worked on developing a green roof model that identifies those plant families with good wind resistance.

A wind resistant plant will possess either light-time activated or embedded spatial separation and protection mechanisms for Calvin Cycle processes.

Parapets are always preferred as wind breaks but architects sometimes develop client-directed roof plans with little or no parapets.  In those cases we must use wind resistant plants to serve as living parapets or wind breaks to the inner green roof.

Thank goodness there are many plants that can survive the vicious onslaught presented by salt spray and winds though.

Florida Green Roofs, coastal dunes are rich in biodiversity with wind and salt tolerant plants perfect for #GreenRoofs

Which ones?

The very best was to know whether or not wind is going to impact your green roof project and to find out what plants can survive these blistering winds is to regularly walk the project site.  

At first glance the coastal beaches may seem to just be 'green' with sand spurs. Ha!  Closer looks will show just how complex plant biodiversity on the beach dune actually is.  There are many, many species adapted to those wicked, punishing salty winds.

The very best was to know whether or not wind is going to impact your green roof project and to find out what plants can survive these blistering winds is to regularly walk the project site. 

Time to go for a walk.