Most (un)wanted plant of the month:
Giant hogweed grows best in rich, moist soils in both open and partially-shaded areas. It will take from 3 to 8 years before it produces seed, depending on how good the growing conditions are.
What makes it invasive?
Giant hogweed produces copious seeds, grows from a dense taproot which keeps producing leaves and is also very dangerous to human health, making it difficult to remove. In the UK, giant hogweed is considered toxic waste.
How to control it:
Control must be conducted very carefully so as not to touch the leaves and get the sap on your skin. Waterproof clothing including gloves, boots and safety goggles should be used. The best way to rid an area of a hog weed infestation is to excavate the plants with the soil, and to bury the waste under at least 2 metres of soil. As this may not be an option for most individuals, another option is to repeatedly remove all vegetation, cut the root crown at an angle (below the soil surface) with a sharp spade, and mulch the area with deep soil or bark, planting with shrubs. Remember to use extreme caution when handling giant hogweed. If the plants have already gone to seed, it is possible to simply cut the seed heads and bag them for disposal, then cut the remaining vegetation and leave on-site to decompose. It will be necessary to return to the site repeatedly over the next couple of years to maintain a hogweed-free site.