Sunday, September 11, 2016

Urban nature: wild by plan



With the emphasis on the environment and battling climate change in the urban environment, the functionality of open green spaces is changing. In both new developments as well as the existing (sub)urban landscape space needs to be allocated for water retention as a result of climate change. Places that are flooded from time to time develop a particular vegetation.  Also studies have found trees to be beneficial in reducing pollution, especially atmospheric particulate matter. This results in the planting of trees especially along roads. Roadside verges are being converted from mown grass into bee ribbons supporting insect life. In other places wild flower mixes are sown to create visual interest (and also showcase the environmental credentials of the local authority).



On dry or sandy soils a different seed mix is used. Directly after sowing annuals like the Poppy (on the left: Papaver rhoeas) are the first to bare flowers. These are included for instant effect. Biannuals flower in the second -or sometimes third- year and will quickly establish on barren soil and develop a ground rosette of leaves. A beautiful example is the Viper's bugloss (Echium vulgare), shown on the right flowering at the top of a bank along an infiltration hollow used to store excess rainwater. Ultimately perennial wildflowers will dominate the vegetation. In the middle a combination of Oxeye daisies (Leucanthemum vulgare), Bird's foot trefoil (Lotus corniculatus) an Red clover (Trifolium pratense) thriving with several types of grass on moist sandy soil.



On loamy or clay soils different plants will thrive, so a different mix of plants is introduces. What germinates and grows well in the specific situation depends largely on the availability of moisture. On wet rich soils -shown left- Comfrey (Symphytum officinale) will dominate together with the Meadow buttercup (Ranunculus acris) and Cuckooflower (Cardamine pratensis) that flowers earlier in the year with pink or white flowers. In shady spots especially under trees or along hedges or in coppiced woodland Cow parsley (Anthriscus sylvestris) can dominate at the height of spring -as shown in the middle. Along roadsides narrow strips of land are sown with wild flower mixes to encourage wildlife especially bees and butterflies. Here an example of such a "bee ribbon" with Oxeye daisy and Cow vetch (Vicia cracca).



Rich wet soils are often regarded as of little ecological value. With careful planning and the application of the right seed mix some lovely results can be achieved. The Meadowsweet (Filipendula ulmaria) feels right at home on heavy, even waterlogged, soils. The creamy white flowers are loved by bees and humans alike. The plant often grows together with Yellow Loosestrife (Lysimachia vulgaris) on the left, or with Purple Loosestrife (Lythrum salicaria). A plant indicative of high nitrogen availability is Hemp-agrimony (Eupatorium cannabinum) with its pink flowers above finely cut leaves that resemble Hemp, hence the name.

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