Saturday, December 19, 2009

Florida Green Roofs - Rainy December

Florida's weather has been at it again.  Drought and more drought then rain and more rain.  Very hot days then cold nights.  Smothering humidity then dry as dry can be.  Tough on the plants.   MetroVerde's MVGR3 system keeps the green roof plants irrigated but not too wet.  Designed for light weight, the engineered soil medium is typically no more than 2 inches thick.  Works well in Florida's harsh climatic conditions.  See or email .

Thursday, December 17, 2009

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.

Saturday, December 5, 2009

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.


Atlantis Living Walls - Living Walls for Florida, Vertical Green

Here is an interesting video of Atlantis Water Management System's Living Wall Concept. The design is solid, especially as the frame is made from 95% Post-Consumer recycled material - good LEED Compliant stats.

I'd make a few changes - such as setting the living wall frame off from the stucco wall by at least 4 - 6 inches and seal any penetrations for anchors with a good low VOC sealant.

Irrigation concept is good too, however I'd certainly capture the water as it exits the bottom of the system to prevent Slip and Fall litigation - you know how prone us American's are to lawsuits...look at the puddle at the end of the clip - Res Ipsa Loquitur.

The extra width will serve to provide stability - especially on free standing walls.

Any ideas how they could be used to treat stormwater?

Wednesday, December 2, 2009

Green Roofs for Florida - Irrigation required? No!

Now, many green roofs are not garden roofs. They are not full of lush, tropical vegetation with nitrogen fertilizers added and irrigated with water that should be charging our aquifers. The latest argument for irrigation of green roofs - is - it is OK if the irrigation water comes from recycled stormwater. Sounds good, right! But how many of proponents of rainwater recycling actually have had rainwater systems in place for some time? If they do they will tell you that the cisterns are empty most of the time! Yes, we have an annual rainfall amount of well over 50 inches per year, but we also have extended periods of time where there is little if any rainfall.

So the proponents of irrigated green roofs say - use city water backup!

I thought we were in water conservation mode here. Watering restrictions, etc...

Just don't irrigate your vegetated roof. Use native species! The other day on a conference call an engineer referred to the native species of plants as 'Weeds!"

It is all perspective. I like the thought of using native species, not irrigating and still having a great vegetated roof.

The above photo is a test panel at UF that has been sitting in a back lot with less than an inch of soil average for almost a year with no irrigation or fertilizer and is still functioning to drink and clean stormwater and provide habitat for pollinators, etc...

No, it is not Jungle Gardens. But it is a thriving, functioning Green Roof! Remember - there is a difference between Intensive Green Roofs that are irrigated, weight 10 times as much or more and cost ten times as much or more - and require massive structural support - and Extensive Green Roofs that are light weight, non-irrigated, non-fertilized and can be put on simple structures.

Sunday, August 16, 2009

Another Green Roof in Florida - with Natives & Non-Irrigated

Corie's roof is planted with Florida Natives. The weight is approximately 10 lbs per SF and the roof is non-irrigated. We will post pictures as the roof plantings fill in with the growth of the native allium seeds.

Saturday, July 25, 2009

Why irrigate green roofs????

Another Reason Not To - Click Here...

Green Roofs, Irrigation, Florida & Hurricanes

Hurricane - High Winds & Non-Irrigation Tests for a green roof test panel. We are collecting data, working with a major university to measure hurricane effects on a non-irrigated, lightweight extensive green roof.

The test panel is a 4' x 10' simulated roof capable of being raised and lowered from a flat elevation to a forty five degree angle.

The vegetated portion is non-irrigated and less than one inch thick.

The panel is being tested under hurricane wind speeds in a wind tunnel. It is also under study for plant growth and survival characteristics under a no-irrigation environment where the insulating qualities are being measured also.

Stay tuned for more information!

Friday, July 24, 2009

Green Roofs in Florida and Irrigation. Is irrigation really necessary for green roofs in Florida?

Here we go again! The draft stormwater manual compiled by the Florida Department of Environmental Protection states that 'Green Roofs in Florida must be irrigated.'

The above statement is simply incorrect and is not a statement we should be hearing from the agency stressing xeriscaping and water stewardship!

I am immediately shut off when I even bring up the topic by many.


I don't know but it is true - Florida Green Roofs can prosper and thrive even without irrigation.

The roof above has done so beautifully! And in-fact is growing water loving sedges this summer (though I imagine they will die when the dry winter hits) - I suppose birds or the wind dropped seed.

Choose your plants wisely. Plant green roofs to survive without irrigation. Be water wise!

Wednesday, July 22, 2009

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!)


Monday, July 20, 2009

Gone mobile! We can now post from the blackberry!

Corie's Green Roof - Jacksonville

Corie Baker is the architect behind the famous Villa Paraiso mansion on the St. Johns River in Jacksonville (see

Her and her husband have a flat roofed addition on their historic Avondale home - and they wanted a MV Green Roof.

Here is a green roof base installed today.

Watch for more pics as the plants are installed!


Friday, July 17, 2009

Life on a Green Roof is Ever Evolving and Constantly Changing - Dynamic Life Cycles of Florida Green Roof

Each new day brings new lessons and data on our Florida Green Roofs.

Our green roofs here in Florida change every day and teach us new lessons each day.

After more than five years of watching plants on roofs I never saw Bahia grass take hold and start to thrive on a vegetated roof. Certainly during the hot drought of February, March and April 2009 here in Jacksonville the grasses didn't show their blades - but today - after a month of steady afternoon thunderstorms there are grasses colonizing portions of our New Florida Green Roof over the detached office building.

I never saw it before and all of a sudden it is here.

Surely with winter it will die back - but the seed heads are full of seed.

We will see if Bahia comes back next spring.

Tuesday, July 14, 2009

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!

Monday, July 13, 2009

Native Plants and Florida Green Roofs

Every good plant person wants to use native species in their landscape. At least we all confess so anyway. Certainly the term is politically correct and in vogue by most regulatory agencies, municipalities and various conservation groups, native plant societies and NGO's.

I have just concluded several years native plant trials on flat and sloped green roofs - extensive green roofs that are not irrigated or fertilized. I've traveled across the State of Florida to various plant nurseries and native plant nurseries. I've purchased and accepted as free native plants to try on the roofs. We've watched them through 20 degree F weather and then through 150 degrees in the summer. Earlier this year we had an 11 week stretch where we received less than 1/2 inch total rain.

Roofs are a rough, tough place to put plants. Most have little concept of the harsh and unhospitable environment most roofs possess. The winds alone over Florida roofs are desiccating and will dry out most plants in a matter of hours.

Plants with high stomata to leaf surface ratio are doomed on a roof. Plants that cannot tolerate high humidity and sever swings in daily temperatures - 60 degrees F is not unheard of - are also doomed.

But Florida's sandhills and xeric uplands support native species with a promise of being able to tolerate the ultimate test of life on a roof.

Native grasses make it for a season or two, but the constant winds weaken their resistance and ultimately they fall prey to extreme drought or cold. We've looked at the leathery leafed native vines- railroad vine, for instance and again - though it comes back when planted in the ground after a hard freeze - it has not reliably recovered on the roof.

The native Allium canadense - or nodding onion - also shows promise.

Yucca's, such as the native Adam's Needle are strong contenders however they have a tall habit and may outgrow a roof.

Of course there are many South African and European plants that survive and prosper in these conditions. But they are not natives.

So why not irrigate? We have a water shortage and a mold problem in Florida. The first time an irrigated vegetated roof leaks and causes building mold issues, precedent will be set for every other building with vegetated roofs and mold, regardless of a leaking roof or not.

And Florida has a serious water stewardship issue. 50% of all potable water use right now is for irrigation. Good enough reason to not irrigated a vegetated roof.

Many will never be convinced of the irrigation issue - but we are making progress. Native can work. Finding the right species for the right roofs takes time.

The above pictures are of Elliot's Lovegrass on a flat trial panel and Allium canadense on a sloped roof.

Send me your thoughts... & Happy green roofing!

Friday, June 5, 2009

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

Monday, March 2, 2009

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

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

Thursday, February 26, 2009

Green Roof Plants - Frost Damage - Florida Green Roofs

Note the frost and freeze scarring on the above plants. Most of the above scarring is minor. These however are the hardy ones (in the winter... - the summer is another story).

Last night the Channel Four weatherperson indicated that this winter had been the coldest since 1985. In my opinion, it has been the hardest on Green Roof Plants since we started putting plants up in the roof gutters years ago to see ow they'd survive.

We have seen day after day of daytime temperatures in the high 70's (F) with high relative humidity just to have a front come through and dry out the air and drop the temperatures into the low thirties and even mid-twenties (F). That is a fifty degree (F) temperature swing.

Add the desiccating winds and damaging hard frosts and you can see why Florida is so hard when it comes to specifying reliable green roof plants.

But the valuable information is being accumulated! We know what plants are reliably evergreen and can withstand the temperature fluctuations and more!

Wow. Florida Green Roofs are an exciting challenge!

Happy Green Roofing. Kevin

Tuesday, February 17, 2009

Native Plants for Green Roofs - Florida

Using Florida Native Plants on green roofs can produce positive ecological results. First, native plants should be acclimated to the local climate and ecotone thus affording greater long-term survival. Second, native plants on a green roof will provide habitat, food and foraging opportunities for local and transient wildlife.

Thirdly, the use of native species is an important step in moving towards restoration of original volumetric green in our Urban Core.

The species pictured here include dwarf love grass, muhly grass, Carolina jessamine, a naturalized Florida rosa species and others.

Happy Green Roofing! Kevin

Monday, February 9, 2009

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

Friday, February 6, 2009

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.

The Stress of Cold - Frosts and Freezes - on Florida Green Roofs

Tonight was the coldest night of the year with freezing temperatures reaching all the way down into south central Florida. It is still in the low to mid twenties in Jacksonville at 5:33 am.

Green roof plants have taken the brunt of the cold - sitting up on a roof, dessicated by the never relenting north winds, unprotected and exposed.

These same plants must survive in the extreme temperatures and humidity levels of the summer also.

I will be posting pictures later this weekend. Some of the plants are bit back and scarred, some may have died - but others are doing OK.

My favorite - Allium species - is a testimony to successful green roof never fails.

Post your results here too!

Happy Green Roofing - Kevin.

Wednesday, February 4, 2009

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!

Thursday, January 29, 2009

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!


Wednesday, January 28, 2009

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!

Wednesday, January 21, 2009

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!

Hard Freezes and Florida Green Roofs - Winter (Hard Freezes - one of the many 'H's GRs face in Florida)

Judy and I have been scurrying most every afternoon to cover plants as temperatures have been dropping into the twenties here in Jacksonville. Looking at the Weather Dot Com it appears that around Tallahassee the mercury has hit the low twenties several times. Walking by our green roofs, I look up with frost blanket in my hand and want to climb up and cover the plants. But I don't.

Our green roofs serve as our best trial panels as we've said many times before. I have finally reached the confidence level that allows me to know the plants will survive. Still though, many of the plants on our green roof are hard to find varieties and the cold north winds are desiccating, unrelenting and potentially fatal to humans, animals and plants.

I am always proud the next day to see the plants stand straight and soak up the sun's warmth. Balancing the choice between those plants, like the sedums that can tolerate extreme cold but melt in the fierce pressure cooker like humidity laden summer heat - and the succulents that can take the tropical heat but not the cold has been the key to success.

There are not alot of plants that fit into the category of withstanding both of the above limiting factors. Then you add long periods of drought and long periods of innundation to the model as inputs and the list of plants that will survive shrink even more.

Finally add the requirement the plants must still look good and not be dormant to the above and the list really becomes small....

So as I await days light to see what damage, if any has been done and add the findings to our resource base - I hope the coldest night so far of 2009 will produce the same positive results as those before.

Happy green roofing in Florida!