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

Coastal Green Roof Plant, Railroad Vine, Ipomoea pes-caprae Creating a Living Roof

Here is another photo of a living, green roof created by Mother Nature's amazing coastal, salt-tolerant beach plant, Railroad Vine, Ipomoea pes-caprae.

Florida Green Roof Plants - Ipomoea pes-caprae, Railroad Vine

This plant is potentially a great addition to any coastal green roof design.  With its ability to grow into the salt water, withstand extreme heat, drought tolerant and inorganic soil media loving characteristics, Railroad Vine is a potentially great choice for many tropical, coastal green roof projects.

Here, in the above photo, the vine has colonized a parking cone, growing up into the top and outwards, creating a 'mini-green, living roof', providing habitat, attracting pollinators and shading the cone.

Nature can teach us so much about living walls and green roof design.

Coastal green roof plant, Railroad Vine, Ipomoea pes-caprae

Coastal green roof plant, Railroad Vine, Ipomoea pes-caprae

Green Roofs Design for Coastal Projects, Florida Green Roofs

Just a quick note this morning.  Nature is the very best teacher about all things #GreenRoofs.

Learning Green Roof Design - mimic Mother Nature, learn from Her

We are working on the design of a green roof for a structure along the seashore.  I learn so much from each site we work with; yes, from the site itself.

Spending time sitting, walking, watching, listening, hearing, feeling, understanding your project's surroundings and immediate ecosystem is one of the best ways to understand the design variables you must consider when planning for a green roof, regardless of the project's location.

Book learning is always good.

But knowing your site is better.  Sit and watch the wind blow through those plants growing on your project's site.  Get a feel for how the sun shines on each different species.  Look for water impacts and sources.

Nature is the very best #GreenRoof teacher around, and best of all she does not charge tuition, she just requests you listen, smell, touch, taste and embrace.

Tropical and Coastal Green Roof Design with Native Plants, MetroVerde Design Video

Green Roofs are complicated enough to design and build.  But those affected by salt spray and tropical storms are even more intricate and possibly problematic. 

Watch Part One of our Design Video for Coastal and Tropical Green Roofs.  Each part is approximately thirty minutes and will focus primarily on selection and layout of native plants for coastal Green Roofs.  Part Two will be available for viewing later this weekend.

Green Roof Plants and Thermogenesis - Strange World of Plants

All plants possess biological systems that directly impact our ecology and the immediate environment surrounding our day to day activities.


After purchasing a truck load of plants on Saturday we unloaded most, however forgot to remove all of the plants from the cab.


Though the night air was cold (6C) when I opened the truck door and climbed in to drive to the market yesterday evening, after dark, I was enveloped with warm, moist air and confused as to why - with the cold dry air outside - the truck windows were fogged over with moisture.  Then I realized the plants were still in the truck, taking in CO2 and pumping moist O2 back into the air.


After spending much of Saturday evening outside taking temperatures with the ExTech IR thermometer, the oxygen and moisture filled truck cab emphasized what I already knew - plant's biological process are complex and have definite effects on their surroundings.


Sometimes we forget just how much plants impact our environment.


However in addition to the wonderful visual greenery (again we sometimes take for granted), plants sequester CO2, produce O2, provide habitat for wildlife in the Urban Core, provide food, fiber and medicine, clean stormwater and provide a myriad of other functions.


All of these factors and processes impact green roofs.  Understanding how these factors interact with the building is important.


This weekend I wanted to gather additional data on heat and green roofs.  My questions were many and included;


* Do green roofs really act as insulation?
* Do green roofs act as a heat sink - storing heat - instead of being an insulator?
* Does green roof plant selection impact the energy efficiency of green roofs?
* Does green roof soil composition impact energy efficiencies of green roofs - and if so, how?
* and a host of other questions.


After spending several hours with the IR, examining plants and green roof systems after dark - and in 6C ambient air, I can say much data needs to be collected, many studies completed and analysis done before we really understand the dynamics of green roofs.


Just as with the fertilizer and irrigation issues (I am always amazed at how some promote green roofs as ecologically friendly and important yet insist for the inclusion of potable water irrigation systems and fertilizer applications), the insulation or heat sink issues just don't seem to be adequately answered.


After collecting temperature data from under green roofs we see a green roof behavioral trend pointing to a heat sink rather than an insulator type system.  In other words, green roofs may tend to absorb heat during the day and then slowly release it back into the atmosphere and building during cooler evening hours.


Yet the complexities of plant species, plant growth characteristics, root systems, stomata to leaf surface area ratios, soil media specific heat qualities and other issues all contribute towards a complex model.


Getting back to the IR thermometer field  foray, some of the more interesting observations we noted were;


* Night time green roof plant leaf temperatures were approximately the same as ambient air temperatures,
* There were variable levels of warmer temperature readings found in the air space under the green roof plant leaves and above the green roof soil media, depending on the time of night and wind exposure - suggesting a level of insulation occurring as a result of leave structure
* The underside of an extensive green roof (3" soil media) stayed 10F warmer than a similar roof with no green roof system - and stayed warmer all night -- up until 5am the next morning,
* Banana plants stayed considerably warmer than ambient air for up to three hours after dark - unlike other plants,
* and other observations.


The banana plant elevated temperatures pointed us in the direction of thermogenesis in plants.  Thermogenic plants are those plants that can generate heat as a result of biological processes. The voodoo lily, Sauromatum guttatum, can generate temperatures of up to 110F - 32C!


There is a great video on thermogenic plants here.


However, the banana plant is not a thermogenic plant and the reason the banana plant stayed warmer than ambient air for several hours after sunset was the plant's high water content.  Water has one of the highest specific heat values of any compound or substance - four times than of limestone for instance.  Because the banana tree was full of water, the solar heat gain experienced during the day only slowly dissipated after nightfall.  Banana trees stayed warmer than most plants after dark because of the heat stored in the large volume if interstitial water within the plant.


It is possible the succulent filled extensive green roofs we are studying that emanate heat throughout the night are behaving like the banana plants.  The combination of green roof soil media and the water therein is absorbing heat during the day - maybe quite a bit of heat - then slowly releasing the heat at night.


The factors involved in modeling this complex heating and cooling dynamic are many and not well documented today.


We think the heating behavior of the extensive green roof is due to water in the extensive green roof plant root systems.  Because the system studied was non-irrigated (nature only irrigation), the soil media was rather dry.  However for heat to continue to be released for long hours, the heat source probably was water - and probably water stored in the underground parts of plants.


We ask ourselves many questions - if water is a significant heat sink and heat source, then do green roofs really act as insulating systems?


If green roofs are heat sinks then how much heat do they dissipate back into a building at night?


Are irrigated green roof systems actually hotter than non-irrigated vegetated roofs or reflective white roofs?  If so by how much?  How much cooling does plant transpiration and evapo-transpiration on irrigated green roofs?


There are many questions to be answered.


As an industry we need to sponsor and encourage more study of green roof thermodynamics.


I'm sure that over time a design model will be developed and accepted by the industry.  in the meantime - data sharing is crucial and important.

Florida Green Roofs (Dead) and Value Engineering?

Living roofs are usually one of the first components of a construction project to become 'value engineered' here in the southeastern U.S.  With an average cost of $20 per square foot for a variety of different green roof vendor projects, the dollar impact on a project can be significant.

Even with the costs, the benefits of green roofs can be many including financial.

Florida dead living roof, value engineering results

Importantly, cutting corners on a green roof system can result in serious performance issues.  The photos here are of a Florida living roof (dead now as of last week) where the client chose a landscaper who had never worked on a Florida green roof before to install plants.

Dead roofs can prevent fire hazards and tort liability issues

Unfortunately, the lowest initial cost does not mean guaranteed performance.

Moreover, lowest costs can sometimes result in highest costs over time.  Especially when the original installer does not remedy the dead plants.

The roof shown here has multiple problems.  In the present condition the dried, dead plants are a fire hazard.  One little spark from a cigar below,  carried up on a wind current could result in serious roof or building damage.

Using a landscape company who does not have roofing insurance can result in liability if a worker falls

With all the weed seed accumulated on the roof, any dormant desirable rootstock will be overwhelmed and shaded out by the noxious plant growth.

The visual failure and negative impact is prominent.  Clients and staff alike may complain about the way the dead plants appear.

THe wild weed seed source has coasted the roof and will choke out any remaining good rootstock

The cost to remove the unsatisfactory material will be much higher than the installation cost of the wrong plant types.

Finally, the client is lucky the landscaper did not have a staff member fall from the roof.  Most ground level landscape contractors are not ensured for working on roofs.  Always check not only for adequate insurance but for applicable state licenses.  In Florida, roof work should include a licensed roofer.

Value engineering sometimes has a way of biting back.  Of course, this roof is in litigation now.  Ultimately though, it will end up costing the client much more than the highest original bid.

For green roofs,  doing it right the first time is important for long term success, regardless of costs.

Green Roof Plant Sleuthing! Understanding why some plants grow better on roofs.

I call the process - 'Green Roof Plant Sleuthing'!

Simply put, Mother Nature is the best teacher for what grows well on a wall or on a roof in hot, dry, arid and monsoon-like climates.

Nature created green roofs cool buildings and provide habitat

When students of Green Roof technology ask me for recommendations concerning plants and green roofs, the first task I suggest is always to do a little Urban Sleuthing.  Walk around downtown, watching your step and keeping an eye out for traffic yet looking up to the city roofs, gutters and tops  of building structures.

Most are amazed to see just how many plants actually grow out of cracks, with minimal soil and survive the typical harsh conditions of a rooftop.

Green Roof Sleuthing is fun & educational!

Excitingly, these naturalized plants can produce a full and flush growth habit, offering an almost tropical look to the roof.

Walking through St. Augustine the other day I ran across many nature inspired green roofs, all quite beautiful and providing habitat, cleaning stormwater, cooling the buildings and pumping fresh oxygen back into the air.

Hidden among the lush resurrection fern were also many interesting smaller ferns, vines and other plant species.

MetroVerde finds many new Green Roof Plants through Florida Green Roof Sleuthing

So next time you wonder about the type of plants to use on your next green roof project, be sure to consult with your local nurseries and growers but also do not forget to do some Green Roof sleuthing yourself.   Take a walk through the downtown and look up.

Chances are you may never use those plants you see growing out of the buildings but then again, knowledge is power, especially when working with plants on roofs!

Residential Green Roofs, Small Scale, Big Impact

Genora's Green Roof,  Jacksonville,  Florida

Genora Orth's green roof may be considered small by some.  Approximately 13' by 10' the living roof captures rain from most of the front porch portion of the historic Riverside Avondale home in Jacksonville.

Anecdotally I estimate of all stormwater flowing through and then off the entire roof, about five percent is intercepted by the living roof soil media and plants.

Individually five percent of a house's roof is not much, however collectively five percent is very significant.

On Genora's roof for example, the 130 square foot living roof over the porch captures another 200 square feet of roof run off from the area above the living roof.

Quick calculations show a two inch rainfall event across 230 square feet of roof would produce about 400 gallons of stormwater.

Normally such an amount coming off asphalt shingles would carry contaminants, not only from the petroleum based asphalt shingles but also those contaminants from the urban core atmosphere.

Jacksonville has approximately 300,000 homes and residential structures, all contributing stormwater directly or indirectly to the St. Johns River and Floridan aquifer.

If 10% of the homes in Jacksonville were to install a living roof on their front or back porch there would be a total of 30,000 homes with small green roofs.  If each green roof attenuated or cleaned 400 gallons of stormwater then the total amount of treated and cleaned runoff would exceed 1,200,000 gallons.

However, just think what would happen if just half of the residential structures in Jacksonville installed small green roofs like Genora's then over 6,000,000 gallons would be cleaned and attenuated before reaching our Floridan aquifer and St. Johns River.

Now consider the fact that it is estimated there are several million residential structures in Florida.  If each had a small green roof like Genora's living roof then close to a billion gallons of stormwater runoff could be intercepted and cleaned before reaching our waters.

Just as the tree lady of India, Janet Yegneswaran plants one tree at a time, small green roofs could cover the urban and suburban core one roof at a time.

Genora's efforts make a strong statement of sustainability, providing us with an example and a challenge to do something ourselves to help clean our rivers, streams and waterbodies.

Green roofs don't have to be big to impact the world.  Small scale green roofs carry a message of powerful intent.

GreenRoofs - bring it all together, Pollination and Biodiversity

MetroVerde Florida Green Roof's summer blooms!

MetroVerde Florida Green Roof Butterflies & Biodiversity

MetroVerde GreenRoof  Late Summer Echinacea Blooms

It is so amazing to watch green roofs grow and provide beauty.  Though we are still in a heavy drought, we have had a little rain last week finally - and the green roof plants and flowers respond with their splendor and beauty!

As the rain hits the roof the water is quickly adsorbed by the plant roots, minimizing urban runoff and scavenging nutrients and other pollutants from the runoff, helping keep our rivers and waterbodies clean.

The wildlife attracted to the green roof is simply amazing to watch.  Such a wide array of insects, amphibians and reptiles now live across the roofs.  A jungle in the urban core field of concrete!

Walking on the roof the oxygen is thick, plants strategically placed near air intake vents for optimum interior air quality.

Carbon is sequestered and life is brought back to the Urban Core.

I love Green Roofs.

MetroVerde Florida Green Roof at Breaking Ground Contracting

Green Roof Designs are different than ground level landscapes. Green Roofer Responsibility.

A perpetual optimist, I always hope for the best from people, groups of people and collectively as companies and industries.  I hope most want to do the right thing when green roofing is in focus.

Rooftops are different than ground level landscapes, but check out the sprinklers going!

Maintaining positive industry reputation is critical to the developing green roof industry here in Florida.  Several bad jobs can label the product as 'defective' and quickly turn a positive business atmosphere and outlook into a negative one.

Those doing green roofs in Florida needs to ask for help from someone who understands the different issues facing rooftop plants here.  Florida roofs are different than the rest of the world.   Importantly, although many landscape companies exist across Florida, a ground level landscape is vastly different from a roof.  Consulting a landscape architect or green roof designer who understands green roof design and plants is crucial for the success of a Florida green roof.

Right now there is a relative large project here in Florida where a nationwide company installed a green roof in October of 2010.  The contractor used sedum, which should have never been recommended or used here in Florida and the plants promptly died.

In an attempt to remedy the job the contractor used a landscape company to install perennial peanut sod as a cost effective alternative.

In my opinion, this was an inexpensive remedy with a plant that is known to die back here with freezing temperatures.  Though green roof plants may be expected to die back up north with cold weather, here in Florida vegetated roofs should be green year around.

It appears that a large amount of fertilizer has now been added to the roof to encourage the plants to take hold and the gutter overflow is filled with algae, speaking of high phosphorous or nitrogen applications.

Right now the roof has five garden hoses slung up to the top from down below and for four hours each day or so, five whirly bird sprinklers are spinning around full blast watering the peanut sod in an attempt to moderate the 120+ F rooftop temperatures and two meter per second desiccating wind (the roof has no protective parapet).

Where the water hits the plants look green.  The other thirty percent of the roof is dead brown. The entire planting is hit or miss.

The sod that is green will continue to look good as long as irrigation water is applied, except where the soil media is being eroded away.

But this is not sustainable and this is not what the green roof industry needs in Florida.  We have a water crises here in Florida and applying large amounts of overhead irrigation to a green roof should not acceptable from an industry perspective.  Moreover, it is not good for the plants as it encourages fungal issues here in our long, hot and wet summers.

A rooftop is not a ground level landscape and must be designed with different restricting issues in mind.

I was always taught to be sure customers received the very best product once you agreed on a design, regardless.

Landscape companies and large roofing companies may have the capabilities to install plants on the roof, but if they do so they seek out qualified design help before experimenting real time.

The green roof industry as a whole deserves and should demand quality work from those participating in the genre.

Green Roofs Teach Us About Plants

We are always very focused on learning about how plants do on the ground and then using compiled data to determine what plants works best on green roofs.


Yet the reverse is true also!  We can take what we learn from green roofs and apply to ground level landscapes with stunning results!


Really cool when we learn from the Green Roof experiences about those plants who do well without irrigation and in extreme heat & desiccating winds.  Roofs are magnitudes more hostile than ground level planting areas.

Native Plants provide beautiful non-irrigated landscape

Species who have proved themselves on the roof are solid choices for most ground level landscapes.

And there are cost savings too!  Here this planting is non-irrigated (the city approved zero irrigation) yet we have a tropical, lush look from two great native plants, Adam's needle and Little Bluestem. The soil prep was special and heavy pine straw mulch applied. Very green in many ways!  For more on this native plant install click here.


Understanding Green Roofs and Green Roof plants pays many dividends.

May Wildflower Green Roof photos from Breaking Ground Contracting, Jacksonville

Here are some photos of the Breaking Ground Contracting food and wildflower green roof in Jacksonville.  Even though we've had a terrible drought, the green roof plants have grown very nicely.  This roof is not irrigated with potable water and uses only HVAC condensate.  Right plant, right place with CAM species on the perimeter and C4 species inside the CAM belt.  Model your design for wind and sunlight!  Enjoy the photos and have a fabulous Memorial Day weekend.  Kevin :). 10-20-30 rule met so far!  We have approximately 150 plants species and counting!

MetroVerde Green Roof for Hurricane Prone Areas, Breaking Ground Contracting

MetroVerde Green Roof for Hurricane Prone Areas, Breaking Ground Contracting

Corn, MetroVerde Green Roof for Hurricane Prone Areas, Breaking Ground Contracting

Day lily, MetroVerde Green Roof for Hurricane Prone Areas, Breaking Ground Contracting

Cathranthus, MetroVerde Green Roof for Hurricane Prone Areas, Breaking Ground Contracting

Gaillardia, Rudbeckia, Native Species, MetroVerde Green Roof

Mint, Herbs, Spices for Green Roof, MetroVerde

More wildflowers, MetroVerde Green Roof

MetroVerde Green Roof Biodiversity

Green Roof Wildflowers, Jacksonville, MetroVerde

Solar Panels and Wildflowers, MetroVerde Green Roofs

Green Roofs Florida, Earth Day Significance - Chionanthus virginicus Planted

Today we celebrate Earth Day here in Jacksonville by planting a Grancy Grey Beard, or Old Man's Beard, Chionanthus virginicus, on the Breaking Ground Contracting living roof.

Chionanthus virginicus ready for planting on the BGC Green Roof today, Earth Day 2011

To me, the tree and the project are very special.  Before moving to Jacksonville we owned a beautiful parcel of land on the Gulf Coast of Florida, one filled with pine flatwoods and cypress swamps.   Chionanthus virginicus grew wild there, along with her evergreen cousin the American olive, Osmanthus americanus, both being members of the Oleaceae family.  The olive is a beautiful evergreen shrub or small tree while the Grancy Grey Beard is deciduous.

In the early spring, along with Carolina jessamine, Chionanthus is one of the first blooms one comes across in Florida's nature and the sight is stunning.  Beautiful white, fringe-like flowers fill the shrub and call to wildlife.

Breaking Ground Green Roof Planting Beds, Solar Panels in the background

Planting a Grancy Grey Beard on the Breaking Ground Contracting's living roof is symbolic of Earth Day's true intent as Breaking Ground's staff are focused on sustainable construction, leading the way for their neighborhood renovation and creating a facility not only serving as an office but as an educational outreach resource for sustainability, to all.

As we celebrate Earth Day in many ways around the world, Green and Living Roofs stand side by side with other sustainability measures, cleaning stormwater, creating wildlife habitat for supporting biodiversity, sequestering carbon, cleaning the air we breath with fresh oxygen, offering educational, economic and social opportunities in the Urban Core and more.

Hope all have a wonderful and sustainable Earth Day 2011.

Florida Green Roof Temperature Trending

Clearly the pattern of green roof temperature moderation, especially on south facing roofs continues.

We will resume our normal technical green roof posts tomorrow and switch over the temperature graphs to a page within the blog.

In the meantime - you may want to check out the great contest for green roof photos on GreenRoofs facebook page by clicking here.

Temperature Difference Green Roofs and Asphalt Shingles

Why We Need Green Roofs

Florida's forests and wetlands bountifully stretch across the state, historically providing an uninterrupted swatch of green to migrating birds and other wildlife.

The same holds true for many other states here in the US and other nations.

When Europeans first arrived in the new world tall forests of trees, vines and shrubs stood, having grown over hundreds if not thousands of years.

Slowly and persistently with population growth, the volumetric green became horizontal green.

Ardea alba, Great White Egret, Orlando, Florida

Working with my son Ruairi last year on his entry for the state history fair, I stopped in Deland to pick up a copy of a DVD documenting the cutting of Florida's great cypress forests.

One of the elderly volunteers told me the story of and showed me photographs of a cypress tree, Taxodium distichum, cut and laying in the swamp waiting to be chained to a steamboat and taken to the sawmill.  The cypress stump measured 25' (7.62 M) in diameter.  The tree required three or four thousand years to grow and one week to fell.

Of the hundreds of thousands of acres of ancient native longleaf pine and cypress trees stretching across the state, all but two or three were logged.  Two ancient cypress trees, named 'The Senator' and 'Lady Liberty' are preserved in a small Seminole County Park, each several thousand years in age.

With the forests gone and wetlands filled, concrete and asphalt spread across the landscape.

Today, wildlife and birds no longer have uninterrupted corridors for travel and like the Ardea alba illustrated above resort to the concrete.

Mother nature though is resilient.  The egret was a juvenile, a youngster maybe six months or so old but was making the best of the urban jungle.  Finding a fast food restaurant and the left over fries, the bird seemed happy.

Plants across the roofs of Florida, the US and the world could never replace the forests we've cut.  But they could however serve to provide a level of habitat now missing in the cities.

Green roofs have been touted as energy savers.  I believe their real value is in restoring volumetric green back to the urban core.  Once green roofs appear then habitat is found, stormwater cleaned, a sense of place created, carbon is sequestered, food can be grown, community is strengthened and fresh oxygen replaces smog.

And tree frogs and lizards will be a healthier snack than the fries for the egret.

Happy Green Roofing!

Kevin

Manatees Gather at Blue Springs, Green Roofs Can Help Keep Florida's Springs Clean

Spring Run - Blue Springs to St Johns River

Today's fun topic is about the West Indian Manatee (Trichechus manatus).

What do Manatees have to do with Green Roofs?  Read on and you will find out.

While it has been an unusually cold winter with lower than normal air temperatures, Florida's springs usually stay approximately 67F (20C).

With the colder temperatures, the rivers cool too.

Because the West Indian Manatee (Trichechus manatus) is a mammal, they are warm blooded and need warmer waters to survive.

So in the winter when the river temperatures plunge, the manatees seek out the constant temperatures of the springs.

Now 67F (20C) is not warm - on a hot 100F (38C) summer day there is nothing better than a jump into the 67F cool waters of a Florida Spring.

West Indian Manatee (Sea Cow or Mermaid)

Florida has a wealth of springs.  Because most of the underlying rock is limestone and much as been eroded into underground caves and tunnels where cold, clear water flows.

Some of these underground tunnels filled with cold, clear water discharge at the surface, creating a 'spring'.  The water flows from the cave, out of the spring and down to a river or lake.

The water is clear, but note the yellowish tint

Florida has over 700 large freshwater springs.  For more information on springs from the FDEP website click here.

Limestone is eroded by water acidified through CO2 in the air.

Green roofs help to preserve Florida's springs and winter habitat for the West Indian Manatee by providing two benefits, including;

Momma and Calf

1. Green Roofs remove CO2 from the air, sequester carbon and produce oxygen, keeping the limestone intact and preventing erosion of the springheads.

2.  Green Roofs remove nitrogen and other contaminants from rainfall.  Without green roofs, nitrogen, phosphorous and other contaminants found in smog and air pollution enter Florida's waterways.  Green roof plants adsorb the nutrients from the rainwater, filtering the runoff and keeping the ground water from building high levels of nitrogen and other contaminants.

Look closely, hundreds of manatees line the far shoreline

Florida's springs have always had clear water.  That is until ten years or so ago.  Now we are seeing more and more springs exhibit the greenish and yellowish tint symptomatic of algae blooms feeding on increased dissolved nitrogen levels.

Green roofs can help stop the nutrient problem and clean groundwater, lakes, springs and rivers.

Green roofs can provide a safe and clean refugee for the West Indian Manatees.


As always, email your questions or comments.

Happy Green Roofing!

Kevin

Green Roofs Help Clean and Attenuate Stormwater Runoff

Roof Drains, Jacksonville, Florida

The photos here are of a commercial facility adjacent to a hospital on Beach Blvd. in Jacksonville, Florida. 

The commercial facility has a large flat roof with stormwater runoff collected in the gutters and directed towards a ditch running through the hospital then down a larger creek/ditch directly into the St. Johns River and out into the Atlantic Ocean.

Roof Drains send water into the St. Johns River

The technology shown is no different that the gutters and ditches we see in excavations in old cities of the Roman Empire.

We've had well over 2,000 years as a civilization to think about our water resources and the way we treat stormwater.

The bad news is our rivers, lakes, streams and oceans have become more and more polluted.  Here in Jacksonville the St. Johns River becomes filled with green algae every summer due to the high nutrient loading in stormwater runoff.

The nutrients are primarily from residential and commercial lawn care and application.  Smog and air pollution is another source of nitrogen, one I refer to as another form of 'slow release fertilizer' becuase the smog deposits on roofs and is washed into adjacent waterbodies during a rainfall event.

The photo depicted here is of the Caloosahatchee River in Florida. 

Though the Caloosahatchee is not representative of all the rivers in Florida, it is however representative of a serious problem we have in Florida - that of nutrient runoff into our waterways.

The good news is Green Roofs can help to reverse the nutrient runoff problem by filtering atmospheric nitrogen and other nutrients from stormwater runoff, sequestering carbon and removing particulate matter that phosphorous may bind with.

Green roofs must take the lead and add zero additional fertilization to our ecosystems.

Green roofs must be designed to survive on atmospheric nutrients, leaf litter and detritus from the green roof plants and adjacent sources, bird feces and other natural sources of fertilization.

To be sustainable, green roofs must not use broadcast type fertilizer applications, fast or slow release.

Green roofs are about being eco-friendly.

The good news, again is green roofs can provide a solution.  Green roofs can:

• Filter and clean stormwater
• Provide much needed habitat for wildlife
• Provide habitat for rare and endangered plants
• Sequester Carbon, Nitrogen, Phosphorous and othe pollutants
• Provide Oxygen and clean SMOG
• Provide beauty to the asphalt jungle

Green roofs are one of the 'Green' answers to the global water quality crisis.

As always email your questions or comments here.

Happy green roofing!  Kevin

Lightweight, Deeper Soil Rooftop Gardens for Permaculture

We planted flat-leaf parsley, Petroselinum crispum; and sage, Salvia officinalis on a small, 3' x 12' ( 0.9 M x 3.7M) green roof section this weekend.

However we incorporated two different design criteria.

Roof Permaculture System Design

1. We used multiple layers of the root mat to create a six inch thick soil-growing layer, and

2. We overlapped the mat to create permaculture type swales.

The system is on a sloped roof with a root and water-proofing membrane over asphalt shingles.

Organic flat-leaf parsley and sage was obtained from Judy's nursery stock and planted.

A well drained soil mixture was used.

Photos will be posted as the roof-top food crops continue to grow.

Roof Permaculture - Food Growing on Green Roofs

We are using our same system that has successfully passed hurricane wind simulation of 130 MPH.

As always, email your questions and Happy Green Roofing!

Kevin

Green Roof Plants - Food, Fiber and Medicine Day Two List

Choosing the right green roof plants can sometimes be a challenge for even the most experienced green roof designer - as we commented yesterday.

Today we will be discussing the next three green roof plants out of approximately forty different species suitable for green roofs in climates similar to those found here in Florida - Arid, Rainy, Hot, Humid, Cold, and Windy.

Again, the basic principles each green roof plant possesses include:

* Drought tolerant
* Hardy against innundation and flooding
* Possesses qualities of either food, fiber or medicinal traits
* Social benefit from beauty
* Non-invasive or pest qualities
* Native species to region
* Provides food, forage or communal habitat to wildlife
* Cleans stormwater
* Good plant for sequestering Carbon

Plants number 6, 7 and 8 are:



Important Food and Fiber Green Roof Plants



Trifolium incarnatum - Crimson Clover

Native to Europe, Red or Crimson Clover makes a great filler plant for in between Green Roof structure plants.  Although not a native, red clover is a good, not invasive species providing pollen, beauty, erosion control and acts as a fertilizer since the species fixes nitrogen into the soil - a 'green manure' plant.

Treat Crimson Clover as an annual on your winter green roof - it will wilt away in the summer humidity - but is worth the seeding exercise because of the stunning winter-time red flowers.

Crimson clover will support wildlife biodiversity.  Bees, butterflies and other pollinators are attracted to Red Clover.



Florida Native Plants for Green Roofs

Andropogon virginicus -  Broomsedges 

There are a variety of Andropogon species growing across Florida.  A beautiful native grass species, Andropogon offers a variety of blues and blue greens along with interesting textures.

Broomsedge, Andropogon virginicus is important to wildlife and promote biodiversity.

I've seen Andropogon virginicus do well on Florida green roofs.  My only caution is they may produce significant amounts of dried leaf litter that could contribute towards fire fuel.  Strategically placed, not en masse, Andropogon virginicus should function well on a green roof as they are drought and innundation tolerant.

Andropogon spp. - Bluestems

One of my all time favorite grasses, the colors in the bluestems are amazing - ranging from blue to silver to blue green to purple.

The above link takes you in a new window to a list of bluestems from short to tall.

I recommend most of these species for green roofs as they are beautiful, drought tolerant and can survive flooding.

Again, watch the clumping of too many of these as they can produce copious amounts of leaf litter.

Again, we will be discussing more species over the next few days.

Feel free to add your comments or email us with your questions here.

Happy green roofing.

Kevin

Green Roofs Florida - A New Sprout - Crimson Clover

Green Roof Plants Florida Crimson Clover Sprouts

Stormwater and Green Roofs.  The Florida Department of Environmental Protection (FDEP) has proposed new stormwater regulations that mandate new development projects and other projects remove nitrogen and phosphorous (along with other pollutants) from stormwater.

We all know nitrogen is a major component in fertilizer.

Plants need lots of nitrogen to grow.

However the answer to clean water in Florida (and across the world) lies not in fertilizing green roofs with added nitrogen compounds.

Importantly, there are many plants that take nitrogen from the air and fix the nitrogen into the soil.  Crimson Clover, Trifolium incarnatum, is one of the most efficient 'green manure' crops.

We sowed a crop of Crimson Clover three days ago on a vegetated roof undergoing renovation.  The first sprout was up this morning!  I'll post photos of how the clover does over time.

Now, the Florida Green Roof industry must move away from being a part of the water pollution problem.  We must move to use of creative fertilization rather than specifying addition of more and more nitrogen and phosphates!

However, even our Florida Department of Environmental Protection's Pensacola office green roof has fertilizer and potable make-up water for a portion of the required irrigation.

How sustainable is this?

Are we seriously sustainable?  Or are we as a Green Roof Industry only trying to look green while banking the bucks?

As always, your comments and questions are welcome!  Email here.

Happy Green Roofing