How Hot Do Green Roof Plants Get? Green Roof Plants For Florida and the Southeast

We are seeing 150 degree F leaf surface temperatures this week in Jacksonville.  You need a plant with a low leaf stomata to leaf surface area ration to survive these temperatures.

Irrigation and Green Roofs, Green Roof Plants and Summer Heat

Green Roof Temperature Data

Summer is here and it is hot on the roofs!  Check out the data below we collected this week.

 Using an Extech IR Thermometer AN200 we measured the surface temperatures for portions of the Florida Green Roof, surface temperatures on plants growing in the adjacent ground and then surface temperatures of non-vegetated roofs.  Readings are an average of July 26th, 27th and 28th taken hourly.  Several items stand out.  The green roof agave leaf surface temperature reached 149 degrees F.  That is alot of heat to subject a plant to.  There was significant difference between the decking below a green roof and the decking below an asphalt shingle roof.  The flower on the hibicus growing in the ground, though a brighter color was generally cooler than the leaf on the same plant.  We are collecting additional data and will be publishing our conclusions in the next couple days.  For more information call Kevin 904-294-2656.

Amazing Green Roof Plants - Plants For Florida Green Roofs

It is the time of year where the sedums and other succulents really suffer here in Florida.  It is concerning to have watched the sedums flourish through the winter drought and cool spring then develop rot.  Unfortunately the daily high humidity found in Florida at this time of the year creates serious pressure cooker like situations on a roof - steam - heat - water.  Most succulents will not survive the summer humidity, and in fact if there are too many on a roof, they will create an area that breeds deseases that can affect other green roof plants.

The moral of the story here is to use a blend of plants - the picture here is of our low leaf littter, low volatile oil containing grasses.  These plants have been raised in greenhouses for over a year with timed watering of 1" per month.

Choosing the right green roof plant will ensure your Florida or Southewastern Green Roof's success.  Call Kevin at 904-294-2656 for details.

Green Walls - Living Walls - Green Roofs - What Plants do I use?

Tip Of The Day.

How do I learn about what plants do best for green roofs in an area?  Begin by driving around and identifying those volunteer species growing naturally in building walls and roofs around your city.

Some will work, some won't - however this practice is a good start to understanding what plants do best without irrigation and in minimal soil.

Call us with questions on your green roof project.

Green Roofs - Irrigation and Green Roofs - Green Roofs for Florida and the Southeast

As I travel across the Southeast, I take the opportunity to stop and study plants growing in different places within the urban core.  I was amazed at the variety of plants growing out of crypts and other structures in New Orleans.  Hot, dry and desolate, the stone structures successfully supported a number of plant species that apparently had been growing for quite some time.  Just goes to show - you do not need to irrigate a green roof.....

Irrigation and Green Roofs - Green Roofs for Florida

The green roof test panel shown here is one year old.  We are preparing the unit for hurricane wind tunnel testing.    The only irrigation the roof panel has had is rainfall, and survived a very dry winter and spring.  Green roofs present a different growing environment for plants than do the ground.  No matter how rocky or little soil there may be, the ground offers a consistently cooler place for roots to exist.  A three inch thick extensive roof soil layer can reach temperatures of 140 degrees F or higher while the ground temperature is significantly lower.  So for plants to survive on a non-irrigated green roof, they must be carefully chosen.

We are raising a new breed of plants in the greenhouse where they are exposed to growing conditions much like those to be experienced on a roof.  Heat and prolonged drought.  With trials well into a year now, the plants go through prolonged leaf impact, however when finally brought out and exposed to rain, the bloom and grow.  Importantly, we look at the potentially for flammability when using plants with dried leaf matter or leaf litter.

One interesting quality we are seeing more and more of is the ability for plants to absorb humidity here in Florida.  Fortunately, even when the temperatures are torrid, the air relatively humidity may be quite high.  Air humidity can make the difference between a plant dying and a plant surviving a long period of non-rainfall.

Finally, with water shortages here in Florida and watering restrictions in place by municipalities and water management districts, why would a green roof designer recommend irrigation?  It is because they do not understand the 'right plant, right place' concept.  We have been working on green roofs for many years and understand those plants that work and those that do not.


Call us to discuss your next green-roof project!  Kevin 904-294-2656