Going Urban - part 1

 A couple of days ago, I had to venture 'into town', something we're avoiding as much as possible at the moment due to the current pandemic and lockdown restrictions. The car was due for its annual MOT and while it was being serviced, I had to kick my heels somewhere - so some urban botany seemed in order and provided a good way to steer clear of any other people that might be about, since everyone avoids the geek staring at the ground and writing things down!!

It's amazing to think that we are now at the start of recording for the next national plant atlas that typically involves 20 years of recording between publications. So it's a great opportunity to get into a variety of habitats and see what's changed. I like urban botanising for two reasons; firstly, it's great fun to see which plant species have found a way to wedge a seed into a crack in a wall or pavement and become the latest plant to conquer new territory. Secondly, our changing climate is seeing an increasing number of introduced plant species from typically warmer climes starting to survive our winters and it's interesting to see just what is out there and can now be recorded as surviving in the environment. In this post, I'll cover the first of these two reasons - plants in cracks!

For me, one of the most amazing thing about plants is their ability - collectively - to be able to colonise seemingly anywhere and this is perhaps never more clear than when we find plants in 'our' urban environments. Any little crack in a wall or pavement seems fair game for a plant's seed to get a hold. If a little bit of organic detritus can find its way in there to act as a growing medium, then even better. As walls age, the mortar begins to crumble between the bricks or stones and it's not long before plants start to appear as part of the 'back to nature' process of decay. Norfolk's coastal towns mostly grew up during the recreational boom years of the Victorian era and the design of buildings from that period seems particularly to offer up some lovely nooks and crannies, while the much older walls of churches in the region - most of which date from the 15th century back to occasionally as early as the 11th or 12th Centuries - are especially favoured by ferns. Here's a picture essay of some photos from my jaunt around Cromer this week, along with some photos from earlier years that illustrate how plants find their way into our lives while our backs are turned!

Seeds from a great variety of plants waft around, either in the air if they are light and furnished with hairs or 'wings' to aid wind dispersal, or along the ground. These seeds tumble around until they fall into a crack where, provided they are not found by hungry birds or invertebrates, the may germinate. We often have an all too thorough attitude to 'tidying up' the streets and as a society we often see these little colonisers as simply weeds, that are getting in the way.

For me, this photo represents the 'Classic Coastal Duo'... Seaside Fleabane (Erigeron glaucus) and Sweet Alison (Lobularia maritima) are plentiful in coastal areas in Norfolk and both originated as garden escapes, with Sweet Alison brought here from the Mediterranean and the fleabane being native to South Africa.

Walls offer both very dry and damp environments and the two habitats attract different plant species. This damp corner on the north side of Alby church presents a classic scene where water runs down from a broken guttering. Mosses soon colonise and provide even better seedbeds as Common Ivy (Hedera helix) takes hold and Tutsan (Hypericum andorsaemum) and Hart's-tongue Fern find little niches.

Ferns are great colonisers of shady walls as they relish the growing conditions and have minuscule spores that waft high on the wind and readily find tiny cracks in walls. In Norfolk, Intermediate Polypody (Polypodium interjectum) is plentiful in such places, such as on this roadside wall at Hunworth.

One of our great colonisers of church walls is Black Spleenwort (Asplenium adiantum-nigrum), here seen on Belaugh church. This plant is plentiful in many parts of Norfolk, yet I have only once seen it growing anywhere other than a church wall! The lime within the mortar makes such places ideal for ferns that would otherwise be plants of limestone outcrops - a habitat that we don't have in East Anglia.

Another plant that seems almost always to be growing from a wall is Trailing Bellflower (Campanula poscharskyana), a plant that naturally grows in limestone hills in the Balkans. It is now well and truly established in towns and cities throughout East Anglia and this plant was found along Cabbell Road in Cromer this week. Later in the year it will have bright blue, star-shaped flowers. 

Some of our native plants are so strongly associated with growing on walls that they have even acquired the habit as part of their name! This photo shows the rock-hugging duo of Wall Speedwell (Veronica arvensis) on the left and Wall Lettuce (Lactuca muralis). The scientific name of the latter even alludes to its love of wall (muralis, as in mural). The speedwell is also a common plant of dry, cultivated or disturbed land and the lettuce can also be found on shady woodland paths.

A number of botanists have built up lists of the plants that they have found growing from walls and it seems that almost anything is possible! Here, a Primrose (Primula vulgaris) grows from the churchyard wall at Matlaske.

Even a Foxglove (Digitalis purpurea) gets in on the habit! Here, on the church wall at Irstead.

Plants that produce heavy berries might seem unlikely candidates to turn up on walls, since surely their seeds would not find their way up there on their own? Indeed so, but berries are eaten by birds and birds regularly stop off on the top of  walls for a quick poop! This church wall at Sprowston has the native Barren Strawberry (Potentilla sterilis) and an introduced Darwin's Barberry (Berberis darwinii) growing out of it, both probably there thanks to the intervention of birds.

Another one from Cabbell Road in Cromer this week is this Hedge Veronica (Veronica x franciscana), one of the shrubby Hebes and one that is commonly grown close to the coast, where it is very tolerant of the salty and wndswept conditions. This species is becoming quite regular as a small seedling in walls and pavements, but plants are often tidied away before they get too large, which is probably reasonable enough since such woody species could eventually damage the structure they are on as they continue to grow. To the left of the Veronica is Pellitory-of-the-wall (Parietaria judaica), another classic wall plant as you might tell from the name and very common in East Anglia.

And on a theme of 'anything seems possible', this germinating Annual Sunflower (Helianthus annuus) seed was a surprise find on a wall in Wells-next-the-sea back in December 2019. Clearly this chunky seed has a story to tell about how it got there, but my money is on it having been tucked into the moss by an industrious Coal Tit, making provisions for the winter.

Moving away from basic walls, the stair wells leading down to basement flats in many coastal Victorian buildings seem absolutely purpose built for ferns. Damp and shady for most of the day, they offer surrogate river cliff habitat. This one in Cringleford is home to a substantial colony of Hart's-tongue Fern (Asplenium scolopendrium).

Of course, one has to keep an eye on plants and woody perennials that can grow into sizeable trees or shrubs are not ideal in such situations. This building in Norwich has a cracked down pipe that has clearly been leaking for years judging by the fine collection of mosses and algae on the wall, but the bristling colony of Common Butterfly-bushes (Buddleja davidii) is a nightmare waiting to happen for someone in the not too distant future!

Anywhere can be fair game as a starting point for plants and surprise finds are far from limited to walls. This Hydrangea (Hydrangea macrophylla) was a bizarre sight as it poked out of a roadside storm drain in Knapton a while ago. How it got there and how it is surviving I'm not sure. It seems unlikely to have come from seed so perhaps it was a small, discarded plant that already had a few roots developed and found itself dropping into a lovely, muddy hollow!

Perhaps taking the prize so far for 'Plant growing in the weirdest place' is this Petty Spurge (Euphorbia peplus) that has germinated from amongst the bristles of the brush that is supposed to be the one I use to clean the car. Perhaps it tells you something about how often I clean the car, then!

In Part 2, we'll have a look at some of the more recent colonists that are turning up and providing us with some head-scratching moments as the latest 'garden escape' from some far flung corner of the globe pops up unexpectedly...