Florida Green Roofs, Six Must Have Living Roof Plants

Enjoy the photos of six of my favorite drought, salt, heat, cold and hurricane tolerant green roof plant species!  See more photos of additional plants on the Green Roof Wildflower website.  Wildflowers on #greenroofs are totally awesome.

Florida Green Roof plant, Coral Bean, Erythrina herbacea
Drought, salt and heat tolerant.  Hummingbird plant.

Florida Green Roof plant, Prickly Pear Cactus, Opuntia humifusa
Very drought tolerant, great coastal green roof plant for habitat and pollinators

Florida Green Roof plant, Fleabane, Erigeron app.
Tolerates wet and dry soils, wind and heat tolerant, excellent pollinator plant

Florida Green Roof plant, Blanketflower, Gaillardia puchella
Amazing hardy green roof plant, tolerating salt, wind, heat and other environmental challenges

Florida Green Roof plant, Purple Coneflower, Echinacea purpurea
Hardy, drought tolerant green roof plant that pollinators LOVE!

Florida Green Roof plant, Black Eye Susan, Rudbeckia hirta
Stunning rooftop bloomer that will flower all summer and call pollinators for miles around

Florida Green Roofs...Cold Weather Impacts on Florida Extensive Green Roof Plants

Here in Jacksonville we are supposed to experience our first frost-freeze of the year tonight - so I am posting a previous post about green roof plants in Florida and frosts. Enjoy and Happy Green Roofing!

The past week, January 5th through January 12th, 2010 has been one of the coldest weeks on record here in Jacksonville, Florida.  Hard freeze warnings have been issued every day.  Temperatures have dipped into the mid to upper teens many nights - - I even had an outside water line burst - my main supply line.

So how did the green roofs fare?  As expected, some of the plants weathered the cold just fine while others sustained slight to severe damage.

In addition to the freeze damage to the leaves and tender stem parts, there appears to be frost damage - due to epiphytic bacteria growth of Pseudomonas bacteria, a gram negative bacteria that also acts as an ice nucelator. From the available literature it seems that the presence of ice-positive Pseudomonas can actually cause ice/frost to form on the plant surface. Frost damages the epithelial layer, in many instances killing the plant.  See the Monday, December 22, 2008 blog about Pseudomonas and green roofs by clicking here.

The plants sustaining the most damage were the Sedums and Aptenias.  Aptenia cordifolia, a South African native is one of the most reliable spring, summer and fall plants for Green Roofs in Florida.  Between the freeze and the Pseudomonas the plants have repeatedly died over the past years on our trials.  A wonderful, thick and glossy low grower, Aptenia shrivels and turns brown in the severe cold, the stems separating from the roots.  I have not seen Aptenia reappear during the spring fresh growth spurts as I have with other species - especially the cacti.

So our data gathering continues and our knowledge of what works and what does not work in Florida's unique environment, grows with time and experience.

One of the surprising victims of the cold were many of the Sedums.  Sedum pachyphytumappears to have sustained significant freeze damage to the leaf structure.  I'll report back on what happens over the next couple weeks.

Happy Green Roofing!

Allium - MV's Bonsai-ed Variety - Green Roof Plants Florida

I'm sold on Allium species for both green roof and living wall plants.  Hardy, evergreen, tolerant of inundation and tolerant of drought, these hardy plants form the backbone of many non-irrigated green roofs.  MetroVerde's bonsai-ed variety is an especially hardy variety - grown in a greenhouse with limited watering - typically les than 1/4 inch per month for over a year.  This picture I took today at University of Florida - we have a panel there - as we've written about before - and the system is non-irrigated, been in a harsh test area for over a year now - and the Allium species are growing strong!  Call Kevin with your low weight, extensive, non-irrigated green roof questions. 904-294-2656.

Another Green Roof in Hot Florida with No Irrigation - Green Roofs for Florida

This a small green roof we did in 2008 at Rob Overly's house in Jacksonville.  It is small (4' x 4') but in a very hot, harsh spot with on shade.

Rob, being the sustainable architect with a flair for clean water - being the water guru for Rotary International and traveling the globe on a mission of Sustainability - approached me and asked if we could do a pilot green roof on his front porch.  Using TPO over shingles and our mat and soil we planted the green roof using garlic chives, yuccas and bulbines.   Much to my surprise - two years later, the bulbines are the survivor champs.  Now birds, pollinators, tree frogs and anoles use the green.

I would have thought the winter cold would have killed them.  I would have guessed the garlic chives would be the surviving species.  However since this was to be a prelude to inexpensive technology in rural mother earth, one of the design criteria was a engineered soil layer of 3/4 inches of less.  This is probably why the garlic chives did not survive.  The TPO serves as the root barrier, and doing an excellent job at keeping roots out of the shingles.

This is an non-irrigated green roof that has survived temps ranges of 10 degrees F to  150 degrees F (measured on leaf surfaces with ExTech InfraRed).  Periods of no rain up 9 weeks and periods of intense inundation.

One of the reasons the section of roof shown was chosen is because it receives runoff from a long valley on the above roof and during a serious rain event there is a flood coming across the vegetation.

Call us with your green roof requirements.

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.

Hurricanes, Wind Tunnel Testing, Florida Green Roofs and more

Extensive, non-irrigated green roofs for Florida and the southeastern US coastal areas.  Your MetroVerde Green Roof does not require irrigation, can survive long periods of drought, inundation, both freezing and sweltering temperatures while treating stormwater, providing wildlife habitat in the Urban Core and creating a beautiful Sense of Place.   Pictured above is the MV ER3 test panel at UF scheduled for wind testing in early 2010.  The test panel platform is adjustable from flat up to 45 degrees.  Because the system is a mat based structure - the roots are embedded into a monolithic, permanent platform - light weight - the MV ER3 weighs approximately 10 lbs per SF.

Plants for Green Roofs in Florida

Bonsai style preparation for green roof plants in Florida is time consuming yet delivers results and is worth the time and effort. MetroVerde green roof plants are grown with no additional fertilizer and rely on native rainfall events for irrigation. The plugs shown above are one year old, having spent their life growing under conditions similar to what they will experience on the roof.

The plants shown here are Allium species - and we are experimenting with the native 'nodding onion' found growing across the southeastern United States.

I highly recommend anyone considering a vegetated green roof to plan well in advance and 'bonsai' the plants - acclimating them to the same harsh environment they will spend their life in on top of a roof.

Remember the 5 'H's of the Southeastern US and Florida - Hurricanes, High Humidity, Heat Extremes (Pressure cooker style), Hard Frosts , and High Winds that dry and dessicate plant leaves.

I wrote a blog entry last year about sprouting green roof plant seeds on the roof they will be planted upon - and though not always practical. In any event, growing the plants under non-fertilized, non-irrigated conditions until they are solidly established is a solid approach to plant success once on the roof.

I've seen too many vegetated roofs fail after the designer and installer use plants pumped full of fertilizer, not hardened off and used to significant amounts of irrigation. Once on a roof, the plants experience shock.

Natives are great - adapted native species excellent too.

Remember, prep your plants long before planting on the roof.

Kevin

From Drought to Rain - Green Roofing Plants Must Survive Drought and Innundation...

These two photographs depict the difficulty of designing a non-irrigated vegetated roof in Florida. The photo depicting the dried look was taken May 3rd, 2009 after two months of intense heat and no rain. The other was taken June 1st after three weeks of rain. The roof plants have responded well and are now thriving. Happy Green Roofing! Kevin

Florida Green Roofs, Green Roof Plants and Freezing Temperatures

Just got back from Tampa again. I came across some native grasses along the way at a small nursery - and brought them back to Jacksonville. They are low profile grasses - nice green color and light, flowing texture - especially for Winter!

I have already placed them up on the roof.

The weather forecast is calling for temperatures to hit the teens to mid-twenties across North Florida - and into the twenties all the way down into south-central portions of the state.

Record temperatures are expected (record lows that is).

Of course, Judy and I covered our citrus and some of our tender landscape plants.

But the exciting part of the cold is to see just how 'hardy' plants are on the roof. Some of my green roofing plants took a hard hit two weeks ago. They didn't die, but sustained some scarring. Others made it through the cold just fine.

One of the more interesting observations I've seen this cold season is that you can have two identical plants on the roof but one plant has been installed earlier in the year and has had a chance to 'harden' off to the harsh reality of the garden roof, while the other freshly installed plant has not. Not surprisingly - the non-hardened off plant suffered much more damage than the plant installed in the late spring.

This tells me that there are ideal months to install green roofing plants. I'd suggest it is best to install cold-hardy plants during the cooler months and cold-affected plants during the pre-summer season (allow the roots to develop and grow into the engineered medium before the stressful weather hits.

I'll update the condition of the native grasses after tonight's hard freeze.

Happy Green Roofing!