CLIFF PLANTS GO MAINSTREAM IN URBAN SETTINGS

Friday, December 21st, 2018

Had the pleasure of perusing Cliff Ecology by Doug Larson, Uta Matthes and Peter Kelly over the winter of 2017/2018. As the season is wrapping up I realized it never got published. Since we are going to be exploring the role of ecological references in urban planting design at Reference: The Natural City I thought it would be a good warm up to go through some of the Niagara Escarpment plants identified in the book. Who knows maybe one day soon we will see the plants shown below growing happily on a building like Bosco Verticale in Toronto.

Photo by corno.fulgur75

First up and in no particular order:

Campanula rotundifolia

Photo by anro0002

Photo by Atle Lundhaug

I just loved this Xanthoria elegens colour story…

Photo by pellaea

According to Lawson et al Cystopteris bulbifera along with Thuja occidentalis and Geranium robertifolium become predictable in local quarries abandoned for 70 yrs or more.

Cystopteris bulbifera

Photo by ArthurVailable

Cystopteris fragilis

Photo by Hugh Knott

Asplenium trichomanes

Photo by Ashley Basil

or the more commercially available Asplenium scolopendrium

Photo by Ashley Basil

Pallaea atropurpureaPhoto by Erutuon

Polypodium virginianum occurs on the niagara escarpment cliff face.

Photo by D.Eickhoff

or the more commercially available Polypodium vulgare

Photo by s4m100

Woodsia invensis mentioned in the book while Woodsia obtusa is commercially available.

Sambucus pubens shrub cliff dweller also commercially available.

Photo by Holy Outlaw

Potentilla erecta

Photo by g e g e n l i c h t

Pinguicula vulgaris

Photo by Björn S…

Canada mayflower grows on plateau forest up to the cliff edge.

Photo by wplynn

Geranium robertianum occurs from the cliff face into the talus slope.

Photo by Dinesh Valke

According to Lawson Prunus, Rosa, Ribes, Rubus, Cotoneaster, Buxus, Juniperus, Thuja, Dianthus, Daphne, Sorbus, Hieracium, Saxifraga all occur on or near cliffs. These are all common ornamental plants!

In Europe plants that grow in walls include Sorbus aucuparia, Sedum Acre, Asplenium ruta-muraria, Polypodium vulgare and Tortula muralis.

Photo by cristina.sanvito

Sedum acre

Photo by anro0002

Species composition is determined in part by wall materials as well as aspect. Lawson et al provides examples of Poa annua as dominant on north facing wall of Trinity College at Cambridge UK while Festuca rubra and Sagina apetala are dominant on the south facing wall. According to Lawson et al the importance of local variation in rock texture, porosity and exposure also play a role. Lawson et al writes cliffs are habitats with minimal human disturbance colonized by non competitive disturbance sensitive plants that grow slowly. uh oh…

Lawson states that cliffs in different regions have few species in common but many genera appear in cliffs around the world. Juniperus, Cupressus, Thuja and Taxus are often the dominant trees on cliffs. Common fern genera on cliffs include Polypodium, Pellaea, Asplenium, Adiantum and Cystopteris.

Other species that showed up on the Niagara Escarpment that I thought were interesting…

Acer Spicatum

Photo by Superior National Forest