Compare and contrast
Published: Mar 28, 2017Some plants are great for wildlife, others not so much.
I was watching the small birds flitting around the old English oak in the Zoo car park the other day. The tree is stag-headed – that is, it has dead bare branches above a crown of still-living branches that have sprouted from further down. In the parlance it has retrenched, which is a natural response to adverse growing conditions.
Oaks can do this several times over their long lives as climatic conditions fluctuate from hot to cold or wet to dry. The tree has seen a lot in its life. It has a dense mantle of Ivy, which may need to be attended to if it starts to overtop the living crown of the tree, but I leave it for now as the birds like it. Evidently, judging by the way the flocks of finches and tits fossick around up there they have plenty of insect life to feed on, and you get the impression that within the landscape the oak is a valuable ecological resource.
In recognition of this, a few years ago I removed a somewhat incongruous understorey of snowberry from around the old tree and replaced it with native woodland species to complement it – field maple, hazel, yew, honeysuckle, wild service tree and small-leaved lime. The new planting now looks really well and provides further feeding opportunities for the birds, which routinely drop down to pick out some morsel before flitting back into the oak again.
Compare this to other spots, where we have a mix of plants from around the world. Now, some plants from faraway places can offer a lot to native wildlife, but others offer very little. A great example of this can be seen just next to the oak, in the form of a grove of Portuguese laurel. Although a fine plant, hardy and evergreen, and in horticultural parlance having few ‘pests and diseases’, it’s ecologically hopeless when away from home. One of the reasons for this is that the leaves generate, of all things, cyanide – crush them and you can smell the typical sickly almond scent – in sufficient concentration to kill almost any insect foolhardy enough to try eating it.
Structurally it’s no good for nesting in, and the dense year-round shade means that nothing but ivy survives underneath it. A bit of a basket case for wildlife, then. The tits and finches almost studiously avoid the laurel in favour of the old oak – and, as far as the car park goes, I know which I prefer, too.
Martin Holt, Paignton Zoo gardener