Wednesday, August 1, 2012

Native Plants for Urban Green, Permaculture & Green Roofs

The bioswale is looking great!
LaSalle Bioswale Project - Native Plants for the Urban Core
We were out on errands day before yesterday and Judy had library books due, so the San Marco library was a stop on the list, and I was thrilled.  You see, Riverkeeper and Coca Cola funded a stormwater project I've mentioned before called a bioswale in front of the city facility.

Of course there were engineers involved (Doug Skiles) and plant people like Bob Chabot and Chris Dailey from the Jacksonville Zoo and Gardens, and others.
The Bioswale takes the place of the old right-of-way landscape
Though a stormwater ditch may not sound much like an Urban Green project, nor may it be as glamorous as a green roof or front yard filled with food plants, it is important to all the above.

I have to keep reminding the botanist in me about the importance of native plants.

San Marco's library bioswale is filled with ethnobotanically important native plants.
Cordgrass, Muhly grass, Cypress, Ilex and curbcuts gather and treat stormwater

However, many times these native plants are looked down on by, yes, even those involved in Urban Green, Green Roofs and Permaculture efforts.

Maybe due to their 'commonness', or lack of pretty, patented fluorescent flowers (though many native species are stunning in their own right), or minimal fruiting-food production, natives are out-of-vogue with a large component of the Urban Green movement.  In fact, in the Urban Farm movement, little if any thought is given to the impact of planting food plants that may themselves be another eventually invasive or monoculture problem.
Native plants provide habitat for native pollinators
Sometimes this may be due to the fact that urban farmers, green roof designers and permaculturists are used to thinking along the lines of only one mindset (including myself).

Yet the plants here are just as rich in ethnobotanical value as any exotic plant such as moringa, without the dangers of becoming invasive.  Though preached and loved as the ultimate plant, moringa has been classified as a potential dangerous plant for native habitats (see Michigan Technological University's website).
Existing utilities were worked around during design and installation
Other times it may be because of a lack of education and information about the true value of native plants to Urban Green, Green Roofs and City Permaculture projects.

But the San Marco bioswale brings all that back to mind very quickly.

The native plants growing in the San Marco bioswale not only clean standing and flowing stormwater, they are able to withstand long periods of drought without additional irrigation.  This is important because of our present water supply crises.  The plants can adapt to either floods or dry periods, without having to turn on the hose.
Native plants provide the transition beauty from street to building
Urban landscape, green roof and farming irrigation add up to be a significant amount of water use in our cities.  Hopefully, projects like the San Marco bioswale can educate us all to the fact that native plants can provide landscape beauty without added irrigation.

Yet there is more.  As I was walking around the bioswale, I noticed hundreds, if not thousands of dragonflies, damselflies and other insects.
Because of low leaf litter rate and ability to survive drought or flood, Cypress is perfect for bioswales
The bioswale was acting as a virtual breeding nursery for pollinators, those same pollinators permaculturists pray for around their gardens.  The native plants provide habitat for native pollinators to breed, forage and live in.  Without native pollinators there can be no food gardens.  Without native pollinators there will be no flower pollination.  Without native pollinators there are no city farms.

Importantly, we must recognize mistakes we as a culture have made in the past bringing in exotic plants for food, erosion control and landscape beauty that eventually have turned into nightmare plants.  Kudzu, wisteria, Mexican petunia and potato vine are just a few of many.  Unleashing plant monocultures that choke out native grasses and other plants has been a process that once we start has been difficult to rehabilitate.

The disappearance of many native pollinators and beneficial insects, amphibians and reptiles can be directly related to the use of food and landscape plants from foreign ecosystems that having once arrived, take over and preclude habitat for the native species.

Once our native species are gone we are left with a hodgepodge of alien plants.

Unfortunately, though gaining in popularity, native plant landscape are still under-appreciated for their biodiversity, pollinator support and habitat providing value.

Permaculture, green roofs and Urban Green have come a long way.  They still have a long way to go with respect to incorporating native plants.

Hopefully, projects like the San Marco bioswale will teach us about why we need a majority of native plant species on our green roofs, permaculture gardens and Urban Core Green.

1 comment:

Monica Barnes said...

I'm sure the local authorities and the other residents will someday recognize the benefits of native plants in greening the bioswale and minimizing the impact of stormwater. Yes, it is true that very few people consider these types of plants as beautiful or attractive given that they have very few flowers – if any at all. However, these plants are very effective in stemming the flow of floodwater and are very adaptable to any kind of weather. They basically need no maintenance, so having them is both strategic and cost-effective.