Why Florida Green Roofs Are So Environmentally Important

Here in Florida surface water can directly flow into the drinking aquifer below the ground in many places.  Here is a video of storm water flowing down into the ground through a karst connection to underground caverns after a recent rainfall event.

Cleaning rainfall runoff with green roofs and other urban greening projects before the stormwater reaches our drinking water supplies makes good sense.

Avoidance of pesticides, herbicides and lawn fertilizers and chemicals is good not only for our environment but also supports a cleaner and healthier place to live in.

MetroVerde's Biodiverse Green Roof. Extensive, Lightweight, Hurricane Designed Green Roof for Urban Core.

Biodiversity in the Urban Core can be truly supported by Green Roofs.  Here the Breaking Ground Green Roof has over two hundred different species of wildflowers, herbs, vegetables and plants, attracting pollinators, amphibians, reptiles and birds. 

MetroVerde Green Roof at Breaking Ground Contracting #Florida-Green-Roof

MetroVerde Green Roof at Breaking Ground Contracting #Florida-Green-Roof

The BGC Green Roof treats and cleans stormwater, mitigates Urban Heat Island effect, sequesters carbon dioxide, fills the air with fresh oxygen, affords educational opportunities and so much more.

MetroVerde Green Roof at Breaking Ground Contracting #Florida-Green-Roof

The BGC Green Roof is a MetroVerde Green Roof, a very light weight system tested by the University of Florida under tropical storm and hurricane force winds with the large wind turbine testing equipment located within the Civil Engineering Department at UF.

MetroVerde Green Roof at Breaking Ground Contracting #Florida-Green-Roof

 The roof shown here has been in existence for approximately four years and is applied directly over white TPO roofing.

MetroVerde Green Roof at Breaking Ground Contracting #Florida-Green-Roof

 Hopefully we will see more and more Green Roofs within the Urban Core as the worth (economic, ecological and social) of sustainable design becomes more and more apparent.

MetroVerde Green Roof at Breaking Ground Contracting #Florida-Green-Roof

Green Roofs Fight Cancer

Green roofs and living walls can help clean the air and allow us to breath easier.

Many geographic locations acros the globe have air contaminated with Volatile Organice Compounds also known as VOCs.

Green Roof plants remove cancer causing VOCs from the air

Volatile Organic Compounds (VOCs) are chemicals created by industrial pollution and automobile engines among other processes.  VOCs are the primary cause of Urban Smog.  

They are also responsible for the formation of cancers, respiratory problems and other serious health issues.

According to the US EPA, the Health Effects of VOCs include:

Eye, nose, and throat irritation; headaches, loss of coordination, nausea; damage to liver, kidney, and central nervous system. Some organics can cause cancer in animals; some are suspected or known to cause cancer in humans. Key signs or symptoms associated with exposure to VOCs include conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, declines in serum cholinesterase levels, nausea, emesis, epistaxis, fatigue, dizziness.

The ability of organic chemicals to cause health effects varies greatly from those that are highly toxic, to those with no known health effect. As with other pollutants, the extent and nature of the health effect will depend on many factors including level of exposure and length of time exposed. Eye and respiratory tract irritation, headaches, dizziness, visual disorders, and memory impairment are among the immediate symptoms that some people have experienced soon after exposure to some organics. At present, not much is known about what health effects occur from the levels of organics usually found in homes. Many organic compounds are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in humans.

For more health information on VOCs from the EPA click here. 

According to a new study - one confirming what we already know - plants -  - clean these harmful VOCs out of the air.   Read about the study in a National Science Foundation Article here.

This study makes it clear that it is especially important to have as many plants inside your building or home as the levels of VOCs inside a structure can be up to ten times the ambient levels outside.

Plants act as filters for air and rainfall, actually removing and utilizing harmful nitrogen.  They also remove carbon from the atmosphere by using CO2 to produce much needed energy compounds and then plants pump oxygen back into the atmosphere.

As we are bombarded with pollutants each day, in our water and in the air - installing interior living walls, exterior vertical green - green roofs and living walls, Urban Permaculture - City Gardens, wildflowers and trees - can pay off with significant benefits.

Ultimately, we may live longer.  Ultimately, we may beat the odds with cancer or respiratory diseases.

Restoring Volumetric Green to the Urban Core is critical.  Today, go out and plant a seed or a grown plant.  Bring another inside.  Hang plants from your patio walls and your kitchen window.  Keep plants in your home.  Install a green roof.

Green roofs and living walls - cleaning stormwater, creating habitat, providing a sense of place and beauty and - importantly - fighting disease by removing pollutants!

Surround yourself with plants today.  You may breath better and live longer. 

Remember, the benefits of adding volumetric green to the Urban Core include;

• Cleaning Rainfall runoff and stormwater
• Providing wildlife habitat
• Supporting biodiversity
• Creating habitat for endangered plants
• Integrated pest management - supporting pest consuming invertebrates and amphibians
• Noise insulation
• Reducing Heat Island effect
• Creating a Sense of Place and Landscape Beauty
• and more

Best Plants for Florida Green Roofs? There are many says MetroVerde!

Best Florida Green Roof Plant?

Metroverde is always working to find suitable plants for Green Roofs in Florida.  For years Northeast Florida has been experiencing a severe drought.  Finding the toughest and most visually appealing is only part of the process.  Habitat value, invasiveness, wind and drought tolerance are other issues we consider.

Green roofs in Florida are harsh places – remember the 7 (or more) H’s:

1. High Humidity
2. Hot, hot heat
3. High desiccating winds (killer)
4. Hurricanes (not the football team)
5. Hard Freezes
6. Horrible temperature swings
7. Hurtful droughts
8. Harmful floods

And we all are cautious about irrigating a green roof (I speak as a lawyer – not a botanist here) – our litigious society has already bred a number of legal articles on green building and tort.  Imagine – the issues of:

• Mold
• Water damage to interiors
• Collapse from weight (water is heavy)
• Bacterial breeding
• and who knows what else…

So if we choose to acknowledge Florida’s water shortage problem and build a green roof with micro-irrigation or no irrigation at all, then we need to look to plants that:

1. Can survive the many H’s
2. Are visually acceptable by the community
3. May be cost-effective
4. Are preferably native species (or non-invasive species)
5. Do not present a fire hazard or contribute too much dry leaf litter
6. Are low maintenance
7. Can survive long periods of drought
8. Can survive twenty inch downpours
9. Resist fungal infestations
10. and much more

Two of the most outstanding plants that almost begin to come close to the above requirements are:
1. Frog Fruit (Lippia nodiflora), and
2. Wild Garlic (Allium canadense)
I’ll be posting more data on these two species over the next couple days.  In the meantime – what are your experiences with these species on green roofs?

Green Roof Plant Dwarfed 2 Year Old Allium Canadense

Sorry Green Roof Design

You get what you pay for.

Sprinklers, erosion and a mess ont he roof

Another photo of a shoddy roof scape, destined to give the site owners a bad taste over green roofs and certainly hurt the reputation of green roofs in Florida.

The plant shown here is perennial peanut, a species that does well in the tropics, but questionable here in Northern Florida where the winter temps drop to the teens on a regular basis.  Though somewhat green now the plant quickly wilts without the overhead spray, most of which is evaporating.  I'm wondering what the owner will say when the roof turns a dead brown with first freeze.

The first batch of plant used was sedum and they promptly all died.  Then the peanut was installed but because the roof has no parapet and desiccating wind sheet flows across the roof, the plants must be watered constantly with over head whirly bird sprinklers.

The sprinkler in the middle is over shooting the roof mostly.  Green garden hoses dangle from the roof across the patios below.

Erosion is occurring, creating ruts across the green roof area and soil media lies in the storm sewer attached to the gutters.

This system belongs to a nationally know company.

It is really unfortunate that the bottom line was the cheapest way out.  You get what you pay for. Potentially grand projects that could benefit the industry can wreck the same industry's reputation.

I would hope better for Florida green roofs in the future.

Otherwise, the product will becoming a pariah.

Green Roof Weeds, Maintenance and Taking Care of Plants on the Roof

This is an update of a post I wrote about two years ago.

I was asked to contribute towards a new municipality green roof regulatory policy, one where there was considerable incentive given developers towards site entitlements if the project would include a green/vegetated roof.

One of the committee members also invited was an accomplished technical/construction specialist - one with multiple graduate degrees in technical and mechanical fields.  But she did not understand plants.

Her past green roof projects had been designed around available landscape plants.  Choose the typical on-the-ground landscape plant and design irrigation and fertilizer and other accessory design criteria to support the landscape plants - was the motto.

Whenever we'd discuss native species or volunteer species showing up on the roof, she'd immediately try to quash the discussion by shouting 'WEEDS!  NO ONE WANTS WEEDS ON THE ROOF!'

I think it was because she felt uncomfortable trying to work with the organic, dynamic complexities of nature.  Obviously she wanted no part of having native wildflowers or grasses on the roof.  Moreover, I've seen some of her 'landscaped' green roofs and they quickly revert back to natives, or as she calls them 'weeds'.  I am sure the selective herbicides are used quite often.

We must stop seeing masses of green and train ourselves to look at the plant.  There are few if any true weeds in nature and on green roofs.

Each plant has its own beauty and purpose, even those obnoxious ones.

I've often quoted Lydia Cabrera in saying "there are more spirits in the plants/forests than in the sky'.

The vegetated roof in Sanford I toured this week was full and vibrant due to volunteer plants.

There are no weeds.

I learned this from my daughter, today.  Though I knew it long ago.

She showed me her photos of one of the most obnoxious plants in my book - Bidens alba (Hairy Beggar's-tick).  Just try walking through a mass of Bidens and wait till you come out the other end of the patch....

I love their masses of white flowers but distrust their desire to bestow me with masses of aggravating seeds.

I almost at this time of the year agreed with the self-centered technocrat who probably couldn't tell bamboo from horsetail or coral honeysuckle from trumpet vine.  I almost shouted WEEDS!

But Jincy showed me her pictures from today.  Ones she and Ruairi took out back.  The Bidens are growing on the roof too.

And Lydia Cabrera is right about more spirits in plants.  And I am right about 'there really are no weeds'....

No need to weed green roofs.  Just step back and admire the Bidens.

Green Roof Beauty - Not Weeds - Bidens alba providing habitat and foraging

Green Roof Wonders - Not weeds, Bidens alba provides nectar

Happy Green Roofing!

Kevin

Wind and Green Roof Plants

Included here are two photos of the same black-eye pea plants.  One is on a wind protected green roof, the other is on a wind exposed green roof.  Note the wind burn on the wind exposed roof plants.

Both looked the same prior to the 48 hour wind storm just leaving (killed 40 persons in the southeast US during tornados).

We recorded between 10 and 20 Km/Hr winds on a continual basis for the 48 hours with almost non-existent water vapor or air humidity.

Florida Green Roof, Wind Protected Green Roof Plants

Florida Green Roof, Wind Exposed Green Roof Plants

Wind can burn or kill green roof plants quickly, taking an otherwise beautiful planting and turning into a brown mess within a matter of days.  Even with more than adequate irrigation water applied - simply because the vascular system of the plants cannot keep up with the demand for water in the leaves.

CAM plants and those plants with stomata remaining closed or closing under lack of water conditions must be used as perimeter wind break plants on green roofs with out parapets or other wind protection if the green roof is not otherwise sheltered.

Understand the different types of photosynthesis green roof plants have.  For a primer, check out the many articles we have posted before on CAM, C4 and C3 plants.

Other helpful sites are included here;

Great Irish Gardening blog article on wind damage in Ireland to garden plants.

North Carolina State University has another brief yet informative note on wind desiccation of plants.

Very interesting and informative Permaculture Wind Break Site.

Remember, your green roof site may receive plenty or precipitation or irrigation water, but if it is constantly exposed to desiccating winds the plants will experience the effects of wind damage.

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!

Plants for Green Roofs - The new MetroVerde Carbon Pirate Variety

First off, even though we are a registered nursery in the State of Florida we do not generally sell green roof plants.  The plants here and the way they were raised are for our own green roof projects.  We are sharing the information of both our successes and failures in hopes we will someday have a greener world.  Our commitment is to restore volumetric green to the urban core.

We've mentioned before in the blog the practice of hardening off drought tolerant and succulent plants before installing them on green roofs, but today MetroVerde officially rolls out its Carbon Pirate (trademarked) line of green roof plants.

What is so special about the MetroVerde Carbon Pirate plant line is the time and preparation put into the plants in anticipation of roof duty.

Realize we focus on the Southeast US and especially Florida, so our approach may not be the best approach for other regional climates.  But here in Florida - green roofs face the big 5 H's, Heat, High Humidity, Hard Freezes, Hard Dessicating Winds, Hurricanes, Heavy Downpours, Hot Periods of Long Drought (Looks like 7 and I could add a Host more) - the point is that once you step up onto a Florida roof, no matter what time of the year, your breath can be taken away.  And you understand why you cannot just plant a nursery grown specimen on the roof.  May look good for a few months but after that - well just look at most of the previous attempts here across the state (except for a select few).

Drought tolerant plants possess specialized physiological processes that respond to changes in nature such as rainfall patterns and temperature.  They have developed these functions over the eons and rely on these adaptations for survival in areas where water supply is unpredictable.  Many have very shallow radial root architectural structure with diameters that exceed many times the plants actual form.  These roots want to grow laterally rather than downward in response to the infrequent rainfalls typical of their native habitat.  During a light rainfall event the stormwater tends to barely penetrate soil surface (depending on soil types).

As the rain ends and the water either evaporates or infiltrates, the drought tolerant plant broad surface area of roots responds quickly, storing the liquid for later use.

Additionally the drought tolerant have developed an array of mechanisms for dealing with drought such as CAM - or Crassulacean Acid Metabolism, and we will discuss these in upcoming posts, but lets get back to root structure.

For example, a two foot tall cholla plant often has a thirty foot architectural root diameter.  The fundamental distinction of any drought tolerant plant is the broad lateral root architecture.  Note the difference between some plants that do well in dry areas yet long, vertical systems that tap into the ground water supply.  Examples of these would include; Acacia, Parsley, Burdock, and Mesquite (whose roots have been know to grow down vertically over 200 feet!).

In choosing a green roof plant you first want to select one with roots that want to grow radially, not vertically.  But there are logistical limitations with plants that have radial root systems - they do not like pots or containers.  They need room for their roots to grow.

Recall the times you have gone to a nursery and purchased a plant and returned home to find the plant's roots had circled and circled the inside of the pot - we call this being 'root bound'.  Not good for the plant.

However, practically speaking nurseries are not going to grow one plant in a large tray because of the economics of space, real estate and cost-effective efficiency (I couldn't afford to either).

Hence the dilemma.  A drought tolerant plant grown in a two inch deep container that is three inches by three inches wide will not survive over term on a green roof.  The available functioning root area will only be approximately four and one half cubic inches.  Now as long as the plant is in the green house with irrigation applied (strange to think of applying irrigation to a drought tolerant plants) the plant will probably survive.   However, if raised in a small pot and irrigated, the green roof plant when planted on a roof most likely won't make it.

Drought tolerant plants for the most part have water intake processes that work gradually.  They are used to taking in required water volumes at a lower rate per root surface area using a large root diameter rather than absorbing large volumes of water with a limited root surface area.

The change from greenhouse container with irrigation to the roof is usually just too much and the plants will not function as expected without intense maintenance, watering and fertilization.

Though a topic for another blog session, my firm belief is because here in Florida we have a severe water crisis and nutrient pollution crisis, designing a green roof with irrigation is a fundamentally not environmentally sound.  I know, the cistern argument - hold the rainwater and irrigate with rainwater, but anyone with a cistern in Florida will tell you it is empty most of the time and then you have to use potable makeup water.....  I'll reiterate - my firm belief is because here in Florida we have a severe water crisis and nutrient pollution crisis, designing a green roof with irrigation is a fundamentally not environmentally sound.

Working with some of our green roof species we've 'trained' (this almost sounds cruel) certain plants to bridge the gap between being raised in containers and roof plantings.  Using drought tolerant plants (we will discuss in future blogs) - and let me note here there is a difference between drought tolerant plants and the succulents and cacti - we are not referring here now to succulents or cacti - using drought tolerant plants grown in standard nursery containers, we apply restricted watering schedules over a long period of time - usually over a year, to harden off the plants and prepare them for roof service.

These plants are grown in hot greenhouses with background humidity levels and irrigation amounts of less than 1/2 inch per month.

Once installed on a green roof with a mat based foundation, their roots quickly grow out laterally and with cumulative input from humidity and natural rainfall, they survive and begin to fill in the roof area.  In contrast to the irrigated, happy plants that are fatally shocked once installed on a roof, these plants are relieved to find their home on a roof.  We call these plants MetroVerde Carbon Pirates (trademarked).  They sequester C through respiration, produce oxygen, clean stormwater, provide habitat and create a much need sense of place.

There is so much to talk about here - tray systems versus mat  based systems, whether or not to irrigate, cost, weight, fire hazards, maintenance, volunteer species, disease - but we have plenty of more blog discussions coming!  In the meantime happy green roofing and as always you can e-mail Kevin with your questions - kevin@metroverde.com.

What Plants Should I Use For My Green Roof?

What plants should I use on my green roof?  I hear this question often.  The answer depends on your site orientation, sun exposure, rainfall amount, location, temperature zone, exposure and a host of other variables.

However I strongly suggest you take a tour around town as a first step in selecting green roof plants.  You will be surprised at what you find.  Look up at the top of buildings, old churches, in roof gutters - especially in older downtown areas.

Some of the most successful low maintenance, extensive and non-irrigated (other than natural rainfall) green roofs have been those pioneer and volunteer native plant species established and growing in gutters and along roof parapets.

If you are serious about understanding green roofs you will take the time to go, look, find, and identify the plant species growing without any additional assistance on the roof of your downtown buildings.

Though these plants may not ultimately be those you use, they will provide a solid understanding of the plant morphology and structure that does well under the influence of the 5 H’s.

Watching Green Roofs in Florida Evolve Over the Years...

It is amazing to watch the plants on a green roof move, find their perfect niche and grow over the years.  The photo here is of a sedum growing down across the roof and into the gutter, then overflowing the gutter and cascading down vertically.  Adding volumetric green to the urban core with Florida Green Roofs! For more information on green roofs, call Kevin Songer at 904-294-2656.

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

Florida Green Roofs, Roots, Liners, Life Expectancy and Shingles

Yesterday I removed one of the original green, vegetated roofs we had installed in Florida - to replace with different plants - an herb garden type.

I was amazed at how the green roof plant roots had attached themselves to the fabric, creating a strong and binding weave - an important consideration here in Florida's hurricane prone environment.

The shingle roof underneath actually looked newer than the day, years ago that I installed the green roof.

Another example of how green roofs can protect the underlying roof membrane (especially non-irrigated green roofs!)

Kevin

Flat Roofs and Sloped Roofs, Green Roofs for both in Florida

Remember though - the plants you have installed on your green roof generally do not like wet feet, so provide good drainage!

Our field panels have shown that green roof systems in Florida with excellent drainage - nothing to hold the water in the soil - grow the healthiest plants.

Many take the opposite approach and install a water retention layer (material like a sponge - and a good way to grow mold and culture up plant diseases). Though a water retention layer will work when rain events are a week apart - allowing for drying time - the retention layer becomes a detriment during periods of daily rainfall events. All of a sudden the drought tolerant plants are subject to wetland conditions.

Therefore - we have found green roof plants (Extensive Roofs - we do not work with the heavier, more costly intensive roofs) - on sloped roofs do the best.

Moreover, engineered soils will last longer when well drained. Water has a tendency to act as a separation agent (dig down into your backyard and you can tell how high the ground water rises because the water separates organics and inorganics into layers).

Remember - well drained systems last longer and grow healthier plants!

A Small Herb Garden on the Roof - An Amazing Architect

Rob Overly and his wife Kate want (Kate's direction the roof plants be useful and practical if on the roof) a small green roof Herb Garden above their front door.

The roof is relatively flat and will receive summer sunlight from mid-morning til mid- to late-afternoon.

We will be installing the roof over existing asphalt roll.

Rob rode his Vespa over last week and we planted several trays of seeds - mainly Garlic Chives, one of my favorite Green Roof Plants. Rob is working on Living Machines and other Green Apparati. He is a great resource for Green Building - find him on the web under Rink Design.... You can also track their project at www.robandkatesgreenroof.blogspot.com

Stay in touch for the up to date reports on Rob and Kate's Herb Garden on the Roof!

Raising Green Roof Plants from Seed - Green House or Ground? No - The Roof!

Tip for the day:

When growing Green Roof Plants from seed - if the destination roof is available for use - grow the seeds on the roof. You will be building acclimation into the plants as they grow and minimize transfer shock.

The plants will be familiar with the light levels, climate, winds and morning dews.

The pictures above are the recent Feburary hard freeze showing on seed trays placed on top of a soon-to-be Florida Green Roof! Once the seedlings are mature the mat and liner will be installed then the plants placed into their permanent Green Roof Home.

Happy Green Roofing! Kevin

Florida Green Roof Plants Withstand the Hard Freeze of February 5th, 2009

Look at the spread in the temperature range. It was in the low twenties at 5:30 am this morning - now at noon the surface temperature of the trial asphalt shingle roof is 120 degrees F.

How do the plants survive?

The above pictures were taken this morning about 7:45 am.

The plants were frozen solid. But they've thawed and are enjoying the sunshine now!

Happy Green Roofing. Kevin.

Plants for Green Roofs in Florida

Wow. I drove to Tampa from Jacksonville this week and witnessed first hand the damage last week's twenty degree F temperatures did to horticulture across the state. We must all remember that even south central Florida may be subject to hard periods of cold, freezes and frosts.

Balance. The word that kept popping up in my mind was 'BALANCE'. In designing a green roof for Florida we must keep in mind the 5 H's (they have grown to five from my initial three) - Hurricanes, Heat, Humidity, Heavy Winds and Hard Frosts.

Choose your planting scheme to include three components!

Number One - use the standard green roof plants that survive no matter what. These include plants that come through hard freezes and boiler-type humidity periods. There aren't many of these but there are a few...

Number Two - Select some of the Sedums that will thrive in the winter. They will limp through the summer though. Their poor summer performance can be offset by Number 3.

Number Three - Select those plants that thrive in the summer monsoons but limp through the winter.

A good green roof plant designer will be able to deliver year-round color and interest.

Remember - we focus on non-irrigated Extensive Green Roofs. Roofs that are light weight - no more than a couple two or three inches think.

Florida is tough on Green Roof plants.

Hands on experience through many years or trials is what will produce the best design for each Florida location.

Happy Green Roofing!

Kevin

Propagating Green Roof Plants for Florida Green Roofs

Propagating plants for green roof projects here in Florida is an important component of a successful Florida GR project.

Knowing a plant was raised in the same ecotone where it will ultimately be used is important. This not only secures LEED credits for local material use (and other credits) but it helps in knowing the plant can survive local climatic conditions.

My general rule of thumb is that, here in Florida, a green roof plant should be grown no greater than 150 miles north or south f the project physical location - no general limit on east/west other than the local limits for LEED credit.

The roots shown on the succulent leaf here developed on their own, on a leaf dropped as mother plants were being pruned, a testament to the hardiness of plants. The above pictures also show the importance of saving pruned plant material for propagation - and in doing so being a good steward of resources.

Happy Green Roofing!

Florida Green Roof Project Continues with the addition of more cold tolerant yuccas....

The New Florida Green Roof Project is moving forward! We've added several new cold hardy varieties of Yucca! Stay tuned for more pictures!