Saturday, September 08, 2007

Invasive Species, Barberry & Landscape Design

Invasive species issues are entangled by traditional ornamental landscape needs and wants. The wicked inconvenience produced by the complexities of individual stakeholders’ ultimate goals provides a salient ripe with emotional, and, therefore, contentious debate. On the one hand, traditional gardeners reach for the barberry solution because it works in the short or near term horizon of accepted landscape practices. In a recent web posting at “Students of Success: Japanese Barberry… A Multi-Use Plant” we find a well written essay on the wonderful reasons to plant Berberis. (see also: Japanese barberry: Invasive Species?)

Bowing to current trends and information, the writer does note the following information in passing: “Barberries are typically found in locations of partial sunlight such as a woodland’s edge. Barberries can survive well under the shade of an oak tree canopy. It is also found along roadsides, fences, old fields, and open woods. These plants can and do escape and are invasive.”

Unintentionally, I am sure, the author lists all the obvious warning signals, but couches the information in its positive traditional mantle. “The bright-red fruits mature in
mid-summer on the bush and remain into autumn and the winter. The berries are small and found singly or in clusters. We sell several cultivars of this species as ornamentals. These plants have good deer resistance. Small thorns act as an invisible barrier to deer. Once they encounter this plant, they nearly have to starve to be found eating them.” More rationally positive information is included: “Japanese barberry was introduced from Japan. It is commonly planted for ornamental value (its scarlet fruit and autumnal foliage make it an attractive hedge), as well as for wildlife and erosion control. It easily naturalizes because its fruit is often eaten by birds, which subsequently disperse the seeds. The plant reproduces by seed and creeping roots. Wildlife is known to eat the seeds and distribute barberries. Branches can root freely when they touch the ground or get covered by leaves, which allow single plants to become quite large.”

I draw your attention to the important traits for the gardener which include deer resistance an important part of the decision making process when designing the garden. Nowhere mentioned is the tendency of the species to use these enumerated traits in natural setting to create mono-cultures or biological deserts as this is beyond the decision horizon of most gardeners. A longer term horizon of effect on the greater local ecology is simply not part of current landscaping paradigms.

To the careful reader, a mix message is embedded, and the weight leans towards selecting this impervious-to-everything, nearly fool-proof species as a great garden choice. The invasive species part of the message is hidden and the consumer plants more. And planting this invasive species allows the gardener to feel good about being environmentally wise, for the plant “feeds” birds, and as it hosts no significant-to-horticulture, known pests other than rust, which is not mentioned, allowing the gardener to feel good about not applying chemicals: a perfect garden plant!

Because we define the problem based upon our desired result, and because the traditional gardener is using a short term result paradigm, the idea that possibly this great plant should be controlled, eradicated, and weeded out becomes a point of deep contention. What are trying to accomplish with our landscapes? What is the proper relationship between our personal gardens and landscapes and the local environment? How will we consider the role of beauty in the issues of invasive species?

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