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Giant hogweed flowers emerging. Leaves: dark green, coarsely toothed and measuring up to 2 metres across. Like the stems, they too are hairy. Flowers: emerge in mid to late summer on top of the stems in umbrella-like clusters. The numerous individual flowers are small and white, and it is common to find more than 80,000 of them on a single plant. |
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Giant hogweed seeds. Seeds: at the end of the summer, each individual flower is replaced by a single large seed. Seeds can remain dormant but viable for several years. Seeds are easily dispersed by water and Giant hogweed can often be found colonising the banks of waterways. |
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Stems: hollow, purple (or green speckled with purple) and covered in fine hairs |
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It is a very tall plant (up to 4-5 metres tall), with large, elongated heart-shaped leaves. It possesses a zig-zag on the stems, due to the alternate placing of the leaves, and the bamboo-like stems are greenish-brown in colour. New growth tends to begin later in the spring than other knotweeds, though flowers still appear late summer or early autumn. The flowers themselves are greenish-white in colour and produced in dense clusters. Rhizomes are often more creamy in colour than the orange of Japanese knotweed. |
