In the last post I touched on plants that find niches in urban environments by growing in cracks and various other nooks and crannies in our human world. The second group of plants that can be studied and recorded in urban environments are initially planted but eventually become a part of the landscape. Many people who get involved in plant surveys don't record such things, which is a shame, because they are certainly a part of the world around us and they will be having an effect on any number of things, especially populations of insects that may find them appealing. It is also worth noting that the Botanical Society of Britain and Ireland (BSBI) certainly encourage street trees to be recorded.
My recent visit into Cromer on the North Norfolk to get the car its annual MOT certificate gave me the opportunity to do some plant recording in town and to muse on a few things regarding urban botany, this time looking more at the exotics that come into our everyday lives, rather than the colonisation of our space by native species...
|One obvious barrier to becoming established is hardiness - the ability of a plant to survive cold weather. For plants from warmer climes, this can be a major issue, although many plants are able to withstand periods of cold, even ice and frost, if they are dry and it is the UK's wet winters that can be a problem for them. This species is Giant Viper's-bugloss Echium pininana which is native to La Palma, one of the Canary Islands. For many years now it is done well in the milder parts of south-west Britain, but winters are getting milder and plants are not only surviving the winter to attain flowering size (which takes two to three years) but its seeds are germinating and young plants are starting to appear outside of gardens in a number of places, even here in East Anglia. This plant is in my garden, but it shows how frosty weather can make it have second thoughts! (The wilting of leaves is actually a good strategy to protect the stem of the plant from the worst of the weather)|
|For comparison, these are the flowers of New Zealand Flax Phormium tenax, a much taller plant with stouter leaves. Note that the flowers are deep red in colour and the petal tips are not as strongly recurved at the mouth.|
|A closer look at the amazingly polished, rich olive-green stems of Umbrella Bamboo. The leaves are distinctive, too, with their very long, drawn out tips.|