Wednesday, March 26, 2008

Landscaping no-no: Currants and 5-needles.

Red-flowering currant, Ribes sanguineum, a somewhat pinker-than-wildtype variety.

Another hummingbird-attracting plant is flowering now. Red-flowering currant, Ribes sanguineum, is a shrub native to southern BC and the US Pacific coast. It has been developed into a number of horticultural varieties and is a very common component of local landscaping because of its early spring colour. Therefore you would be advised not to plant a five-needled pine (five needles per bundle), such as western white pine, around here.
Why?

Because Ribes spp. (currants and gooseberries) serve as alternate hosts for white pine blister rust, Cronartium ribicola, which can kill young five-needled pines and damage more mature trees.

The fungus is native to Asia but was carried to North America in the early 1900s after becoming established in Europe. It has a very inventive life cycle that involves five types of spores (two in the pine, three in the Ribes).



Trunks of infected pines, whitened as a result of sap leakage, known as resinosus, from last summer’s release of aeciospores, which were then, if the wind was cooperating, carried across a parking lot to infect a stand of red-flowering currant. And on it goes.

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