One of the sustainable management practices I aim for in the woodland is to remove invasive plant species. These include Japanese knotweed, rhododendron and Himalayan balsam. I’m winning (I think) with the rhododendron and the knotweed but the balsam is able to propagate at a phenomenal rate, easily outstripping the rate I can remove it.
This impressive invader can grow from seed to 10 foot triffid in just a few months. It outcompetes and shades out all native plants, including bracken, grass and nettles. Its other key to success is touch activated, explosive, seed pods! In late summer as the wind moves the head of each plant, the pods explode, sending thousands of seeds dozens of feet in every direction.
I’ve pulled up thousands of these plants, prior to the seed pods forming, in an attempt to halt their spread. However, it always manages to outflank me. Every time a tree falls, the balsam is quick to utilise the additional daylight. Seeds lay dormant for years, germinating when a gap appears in the tree canopy.
On a partially positive note, the Himalayan balsam is a good source of nectar for pollinating insects. This may be good for the bees but not necessarily for pollination of native plant species which have less nectar available.
So, the battle of the balsam will continue, even when it seems a thankless task. It may take over clearings in the summer but it cannot penetrate where the tree canopy is continuous. Ultimately, the woods will win the war!