Florida Living Wall and Green Roof Plants, Nature Found

Some of my best learning experiences with green roof and living wall plants come from Mother Nature.

Florida Living Wall & Green Roof Plants Nature Selected (ferns), Ft. Pickens, Pensacola by Kevin Songer

Mother Nature is especially instructive about nature irrigated plants growing in sea salt influenced areas; up the sides of masonry walls and across barren roofs.

Florida Living Wall & Green Roof Plants Nature Selected (Bidens alba & ferns), Ft. Pickens, Pensacola by Kevin Songer

These photos here were taken on the ocean front walls of the old brick Fort Pickens in Pensacola, Florida, US.

Old forts and other relic structures that have been in existence over time are plant laboratories, experiments in drought, heat, wind and salt tolerance.

Florida Living Wall & Green Roof Plants Nature Selected, Ft. Pickens, Pensacola by Kevin Songer

Another fort, Castillo de San Marcos in St. Augustine, Florida as been surveyed by biologists and the limestone walls found to grow over fifty different species of plants. 

Although in reality most green roof and living wall designers do not use these specific plants typically found growing across structures, the knowledge gained from examining wild roof and wall plants is invaluable.

Identifying and classifying these found plants as to their Genus and Family classifications can help select other related but more suitable to vertical landscape plants.

Florida Living Wall & Green Roof Plants Nature Selected, Ft. Pickens, Pensacola by Kevin Songer

Moreover, understanding the C3, C4 and CAM photosynthesis pathways evolved by these plants provides a solid basis for green roof and living wall design.  

Examine those plants you seeing growing downtown when you are out and about.  Nature has so much more to teach us than the most detailed scientific manuals!

Florida Wildflower Haiku & Art, Lyre Leaf Sage, Salvia lyrata

Florida Wildflower Haiku & Art, Lyre Leaf Sage, Salvia lyrata

Florida Wildflower Haiku & Art, Lyre Leaf Sage, Salvia lyrata by Kevin Songer

...

native purple blooms
hummingbirds steal a sip and
chase off butterflies
…
Lyre-leaf sage is a Florida native and drought tolerant wildflower I see growing across lawns, along roadsides, in fields, meadows and under the forest canopy.

Lyre-leaf sage leaves are lyre-like in shape with deep purple and green colorings. Their light blue flowers provide nectar for hummers and butterflies. The over-lapping leaves of adjacent lyre leaf sage plants keep other weeds down and provide a neat, well-cropped perennial native ground cover appearance. Lyre leaf sage has been one of my favorite and most reliable green roof plants.

Lyre leaf sage has also been used traditionally as a cancer cure. This healing practice was based on a theory that because the plant quickly spread, creating densely populated patches, it must be a natural cure for likewise rapidly spreading cancers. 

Lyre leaf sage is an amazing Florida native perennial, landscape or green roof plant superb in its attraction to pollinators, hummingbirds, bees and butterflies.

Florida Native Plant Art & Poetry (Green Roof Plant too!), Shiny Blueberry, Vaccinium myrsinites

Florida Nature Haiku for Friday morning, Shiny blueberry, Vaccinium myrsinites

Florida Haiku, Shiny blueberry, Vaccinium myrsinites by Kevin Songer

...

I always wondered
bout shiny blueberry’s taste,
rabbit got there first

...

Shiny blueberry is a diminutive member of the blueberry family offering winter seasonal beauty with its namesake bright and shiny red and green leaves. During the growing season shiny blueberry is usually obscured by taller growing plants. Shiny blueberry produces large amounts of fruits sought after by small mammals, birds and other foragers. I see shiny blueberry growing along most trails hiked.

Shiny blueberry makes a good evergreen & salt tolerant green roof & landscape plant too!

Florida Green Roof and Living Wall Plants, Salt Tolerance Lessons from Mother Nature Ferns

One of the greatest learning centers of #greenroof and #livingwall knowledge can be found on and across the buildings in any local downtown, urban core area.

Ferns growing unattended on old brick adjacent downtown ocean pier, Kevin Songer 

Every living wall and green roof designer, as well as landscape designers and botanists should carry a 'found plant' journal to record information when they come across such resilient plants as those growing in the cracks and crevices of building walls and roofs, without soil media or added irrigation.

Ferns growing unattended on old brick adjacent downtown ocean pier, Kevin Songer 

Looking back across the decades, this is how I learned what I did concerning shallow root growing systems, nature irrigation and plants suitable for hot, windy, salty environs.

Ferns growing unattended on old brick adjacent downtown ocean pier, Kevin Songer 

These ferns are growing on a wall adjacent the downtown pier in Pensacola, exposed to desiccating winds and a barrage of salty mist.  And they seem to be thriving.

Always keep an eye out for those free lessons from Mother Nature about living wall and green roof plants!

Salinity Tolerance of Plants (Reference Link)

Here is a link for a very useful plant salinity tolerance chart I find useful in coastal green roof design, published by The WateReuse Foundation.

The WateReuse Foundation's helpful Salinity Tolerance Chart for Plants.

Florida Green Roof Plant Root Structure, Horizontal Root Architecture

Green roof plant architecture is an important biomechanical component of all green roof design, construction, installation and maintenance activities.  In the end a green roof is first, foremost and all about the plants.

Florida green roof plant root architecture - beautiful horizontal root structure

Without the happy, thriving plants, there is no green roof.  Possibly a brown roof but not a green roof.

I think the Florida extensive green roof root structure depicted here in these photos is simply beautiful.

Green roof plant root architecture -  horizontal root structure growing into anchor

An understanding of green roof plant root architecture is one of those fundamental design talents that every green roof professional should possess.  Some of you will have learned about green roof plant root architecture from years of observation, hands-on planting and study of how green roof species grow, others through educational programs.  I examine root structure across green roofs every chance I get.  

My preference is shallow soil media and unimpeded horizontal growing space for green roof plant roots.  I do not like sectional barriers that may limit horizontal root growth and ultimately cause root circling-root bound growth patterns.

These grasses possess good green roof plant root architecture - not too aggressive but sturdy

Another reason I prefer unimpeded horizontal root growth opportunity on a green roof is because I believe green roof plants will over time, relocate themselves or their offspring to the best place on the roof for their particular species survival.  Yes, plants do move through root biomechanic mechanisms.  It is poor planning to restrict green roof plant root architecture any more than necessary.  Just think of how many times you may have pulled a plant from a nursery tray or pot with twisted and circling roots that have practically strangled the plant.

An anchor system may keep plants on a roof during tropical storms

In addition to catering to the green roof plant through design of open space for root growth to occur we like to provide the roots an anchor to grow into.  There are many different approaches one can take when providing an anchor, including cables, mesh, netting or fabric.  By permanently attaching the anchor material to the roof you create a green roof plant growing system that may be resilient to tropical storms or cyclone winds.

Unimpeded root growth prevents strangulation of green roof plants

Using this approach we have created green roofs that have stayed in place when blown with 130+ MPH winds.

The grasses in these photos show this principle in practice.  Using a small, mock up green roof growing system these plants have embedded their roots into a nylon fabric, creating an impressive anchoring form of root architecture and growing in a well defined, horizontal fashion.

A good green roof plant architecture will create a monolithic growing mat with plants anchoring each other

While some prefer deep plantings with roots reaching down vertically, we find horizontal root structure strategically places roots in an optimal position to absorb those frequent one half to two inch afternoon rainfalls here in Florida.  Rain water usually stays in the top inch or so of the green roof soil media.  With a horizontal growth pattern, green roof plants can take advantage of this rainfall where deep roots may have less rain reach down into deeper soil horizons.

If you are wondering, the photographed soil media contains less than 5% organic material.  The bark-looking chips are actually ground recycled rubber tires.  This is an experimental soil media, one we do not use on actual green roofs due to fire ratings.

Know your green roof plant architecture.  Remember, in the end a green roof is first, foremost and all about designing a growing system that keeps the green roof plants happy, healthy and surviving in the long term.

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

Coastal Green Roof Plants and Cross Section Design for Florida and the Tropics

Designing any green roof involves integration of many site physical, meteorological and biological variables, the actual creation of an ecosystem so to speak.  Coastal green roofs, those with salt impacts, are especially complicated.

Green roofs for coastal structures can present complicated issues to overcome +MetroVerde

Among the biggest variables to be considered during design are wind, salt and fire.  Salt spray will kill most landscape plants.  Around the clock steady to cyclone-strength winds can strip soil media right off and out of a green roof, rendering the system uninhabitable and possibly sandblasting an adjacent structure.  Accumulated biomass can fuel a lighting started wildfire across adjacent lots, wind carried sparks igniting a dry living roof and burning through a roof deck.

So we look for those plants that will grow despite salt, continual desiccation, fire potential and the geological components that successfully support them when designing a coastal green roof.

Coastal Green Roof succulent, seashore elder, Iva imbricata +MetroVerde 

Not only do I enjoy walking along the dunes because of the sense of beauty, the salty smell, the warm sun and sense of relaxation, but the seashore is rich in examples of vertical green, nature created green roofs and native living walls.

Coastal Green Roof plant, seashore elder, Iva imbricata +MetroVerde #greenroofs

Surprisingly, here in Florida there are some really good plants for a coastal green roof.  A walk along the dunes relaxes and teaches.  I recommend a good handbook, one such as The Smithsonian Guide to Seaside Plants of the Gulf and Atlantic Coasts or Florida's Living Beaches.

Native salt tolerant living walls by mother nature +MetroVerde , Florida living walls, Dune Daisy

Mother nature also does an awesome job creating spectacular salt and drought tolerant living walls along the shoreline.  Better than any design guide, beach strolls with camera, pencil and paper will show the designer what works and what does not.

Native salt tolerant living walls by mother nature +MetroVerde , Florida living walls, purslane

The following is a partial list I usually see growing well along the frontal portion of the dunes, in the harshest and most exposed areas.  I would use most any of these on a coastal green roof in the tropics or along the Gulf and Atlantic shoreline.

• Seashore paspalum, Paspalum vaginatum
• Seashore cordgrass, Spartina patens
• Panic grass, Panicum amarum
• Dune daisy, Helianthus debilis
• Beach morning glory, Ipomea imperati
• Rail road vine, Ipomea pes-caprae
• Seashore elder, Iva imbricata
• and Spanish daggers, Yucca aloifolia

But there are many more waiting for the designer to discover themselves!

Of course wind is a big challenge.  Wind can kill those plants not possessing protected photosynthesis pathways.  It is always good to review the differences in C3, C4 and CAM pathways when designing any green roof, but absolutely crucial for a coastal green roof.

Coastal Green Roof Cross Section - Typical Design +MetroVerde copyright MetroVerde 2014

Above is a general sketch of a design approach we may take in creating a coastal free roof subject to cyclone winds.  Of course the roofing assembly will need to be fire rated Class One.  Your roofing contractor working with the roofing supplier can specify the appropriate fire rated materials.

If you use all succulents on the coastal green roof you may not need to design in buffers, yet even the juiciest succulents can burn under the right conditions.

Be sure to follow ANSI, IBC and local standards and codes when designing a coastal green roof.

Seaside green roofs can be very complicated to design, but the very best teacher is always available.  Just hop in your car and drive down to the beach.  Mother nature's creations are phenomenal!

Aptenia cordifolia, tropical green roof plant

Aptenia cordifolia aka ice plant or baby rose plant is a native to the southern Africa geographic region. Aptenia is a beautiful, drought tolerant tropical green roof plant and does well in some Florida environments however the green roof designer should be aware that high humidity loving fungus or below freezing temperatures may very quickly decimate an Aptenia green roof planting. Despite these issues, Aptenia is a lovely non-native horticultural specimen that will turn heads. I would use this drought tolerant plant sparingly on tropical green roofs and only in areas needing significant color splash. When used appropriately she offers significant eye appeal!

 

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Green Roof Plant Design - Understand Heliotropism and Paraheliotropism

Understanding photosynthesis processes in green roof plants is crucial to the green roof designer and we have discussed the difference between C3, C4 and CAM photosynthesis processes in prior notes, including;

• CAM Plants for Green Roofs, Effects of Heat and of Humidity
• Adaptation and Green Roof Plants

• Green Roof Vegetables - A List of Recommended C4 Plants

   

   

   

Under Intense Sunlight Leaves Fold to Prevent Desiccation

Yet nature is complicated and does not limit herself in resisting environmental stressor conditions to just the above three types of photosynthesis processes.  In fact, some plants have evolved other survival mechanisms to help prevent dessication and to conserve water, especially in arid and hot climates.

Some plants, and many of these are excellent species to use on Green Roofs, can move, open or close their leaves to prevent dessication.  This is commonly referred to heliotropism and paraheliotropism.

Cowpeas and other plants for example possess the ability to adjust their leaves position to either increase or decrease the amount of leaf surface area receiving direct sunlight.

Under optimal Sunlight C3 Leaves Open Widely

Under Optimal Sunlight Conditions C3 Leaves Open Widely

Heliotropism is the term used to describe a plant's actions when it orients leaves to receive more sunlight and thereby increasing photosynthesis capabilities, i.e. - more CO2 fixation.

Diaheliotropism describes a plant whose leaves actually track the sun'd path, maximizing solar contact.

Paraheliotropsim denotes a plants actions similar to the above photographs.  During paraheliopropsim, plants may fold or move their leaves to either;

• Minimize solar contact, or
• Minimize total leaf surface area,

either way reducing water loss and preventing desiccation.

Though C3 plants such as the beans - and most other of the world's food plants except the grasses, maize, and sorghum - do not possess as complicated a multi-cellular Calvin Cycle as C4 plants and are more susceptible to drought, they - through Heliotropism biomechanisms they do possess their own unique desiccation prevention mechanisms.

Green Roof designers take note!

Low Cost Greenhouse for Green Roof Plants or Urban Core Permaculture

We are now proud owners of a low cost, easy to build greenhouse in our Urban Core backyard.

Low Cost Seed Starting & Green Roof Plant Greenhouse

Greenhouses are so very useful in starting seeds, rooting cuttings, potting up plants and providing warm weather plants a head start on the growing season.

Greenhouse's interior includes areas for potting plants, storing soil media, supplies and plants

Greenhouses though can be terribly expensive when purchased as kits.

Our greenhouse above is eight feet wide and twenty eight feet in length.  Height in the center is ten feet.  This gives us plenty of room to move around, store supplies and start seeds.

Growing areas are also added under some of the shelves and in a growing extension to the right of the front door.  Plans for this growing area include tomatoes and peppers.  Plastic can be added over the hoops if our Florida nighttime temperatures drop too low.

Cost for the entire structure was less than two hundred dollars.  Much of the material used was recycled from other construction projects or salvaged from neighborhood throwaways.

The greenhouse beginning, a frame from recycled fence components

The greenhouse project was begun by hammering used fence posts into the ground and adding horizontal shelf framing, all fastened together with plastic wire ties.

DIY Greenhouse Frame detail

Grey plastic electrical conduit (one could use bamboo) was inserted into the top opening of the fence posts, 'looped' over to the opposite side of the greenhouse and inserted into the post on the far side wall.  The grey electrical conduit costs less than two dollars for a ten foot section and lasts for many years in outdoor service.

Greenhouse frame ready for plastic covering

Finally, four or six mil plastic was added over the hoop rafters, shadecloth added to one end and lattice around the bottom edge.

The entire structure is held together with electrical zip ties.  Our other greenhouses we've built similar to the above have easily survived numerous tropical storms.

Grapes are now planted to several areas around the base of the structure.  Grapes will help cool the greenhouse in the summer and when their leaves drop, allow for solar heat to fill the growing area during winter.

Greenhouses don't have to be expensive to be functional.  Once the coral honeysuckle, grapes and other vines weave their tendrils into the lattice work, pollinators should come in droves.

Hoop architecture with inexpensive conduit has proven itself year in and year out.

DIY greenhouses can add wonderful opportunities to any urban core permaculture efforts!

Green Roofs and Biomimicry's Lessons

An understanding of proper plant use for Urban Greening projects, including green roofs and urban permaculture gardens can come from many sources including, research, books, libraries, on-line information sharing and hands-on experience.

Florida Green Roof Plants - Frog Fruit crows across harsh, hot coquina sea wall boulders

One of my favorite ways to learn about what species of plants to use and how to grow them across cityscapes is to study successful plant habit in harsh ecosystems.

Those plants growing well under the influence of extreme heat, high humidity, strong desiccating winds, intense light or shade levels and other environmental factors will  usually survive on a city roof, against a wall, on a patio or balcony and in a windowsill.

Too many times designers try and use those plants that need to be gently cared for in cityscapes.  Ultimately the plants die and the urban greening project is shelved for another with less perceived maintenance requirements.

Florida Green Roof Plants - Nature's Examples are the Best Way to Learn About Urban Greening

However, there are many places to find the results of nature's selections and choices.

The beach and her sand dunes; hot, dry roadsides; Urban rooftops; gutters on buildings, vacant lots are just a few of many mini-biomes presenting opportunities for learning about plant growth habits, root architecture, soil, water and nutrient requirements and more.

This week I was walking along a coquina rock seawall.  I cannot go far with my dissected aorta and many times, walking ten feet or so is enough to tire me to the point of sitting down to rest.  The slowness has advantages though and stopping more often allows for opportunities to examine small outcrops of plants in detail.

The coquina boulders in front me, though they were surrounded by salt water, buffeted with strong winds and unrelenting sunlight, supported an amazing array of lovely plants and wildflowers.

Those plants I saw on the boulders, the Frog Fruit, Hydrocotyle, native succulents, many of these we have successfully used across green roofs in North Florida.

Nature can teach us many things.  We just need to stop and look.

Wildflower Green Roof photos from Breaking Ground Contracting, Jacksonville

Yesterday's blog note focused on the Green Tree Frog climbing the Breaking Ground Contracting office wall, Florida Friendly and drought tolerant species, native plants and the importance of Urban Green for habitat.

These photos from May of 2011 illustrate how Urban Green can be established to create habitat corridors through out the Urban Core.  Native plants, Florida Friendly species, vegetables, grasses and more live on the rooftop garden.

The Tappouni sisters' efforts with 'greening Jacksonville' are part of an important sustainability web being woven by the next generation.

"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 irrigated with rain 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!. 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