Changing of the seasons

October 5, 2022

Panshanger Park is 1,000 acres of countryside situated between Welwyn Garden City and Hertford. Herts and Middlesex Wildlife Trust is working with the park’s owners, Tarmac, and Herts County Council to manage the park for both people and wildlife.

We are all feeling the change in the season this past week. A cooler breeze, evenings noticeably drawing in and our summer migrants preparing for their long migration back to their winter residences.

During this time of seasonal transition, it seems a good time to reflect back on the summer at Panshanger Park.

As all green spaces this summer, Panshanger has been various shades of yellow and brown over the past few months. But the passing storms provided a bit of relief from that and the grass, as it does, got to work growing very soon after the rain!

The dry summer didn’t seem to stop the growth of the Himalayan Balsam along the lake margins and river banks. The ever-enthusiastic Panshanger Park volunteers have been out in force for the last few months doing a great job at clearing as much as possible of this plant.

Himalayan Balsam is an invasive, non-native species which was introduced by the Victorians due to its attractive pink flowers. Unfortunately, this highly adaptive plant found growing conditions in the UK to its liking and now most rivers in the country have some, or a lot of, Himalayan Balsam growing along the banks.

You may have seen the large piles of pulled balsam around the site – evidence of the volunteers’ hard work at removing this plant. It is all done for a good reason. Left unchecked the balsam could dominate a river bank or lake margin, outcompeting all the native plant species, making the plant life very homogenous and reducing biodiversity.

Other summer times species are just passing through. This month, a visitor to Panshanger has been the Clouded Yellow butterfly which migrates to the UK from the Mediterranean for the summer months. Although some years there are many of these bright butterflies to be seen ‘Clouded Yellow years’ – others there are only a few. Keep an eye out for this bright yellow butterfly over the next week or so before it heads Southward.

So, as we say farewell to our summer migrants we can begin to look forward to the changing colours of the leaves and welcoming the incoming winter migrants, such as the wildfowl, to the lakes.

If you would be interested in events or volunteering within the park, more information can be found at

Jo Whitaker is the Panshanger Park people and wildlife officer.

She works for Herts and Middlesex Wildlife Trust and her role is funded by Tarmac.

A Clouded Yellow butterfly a summer visitor to the UK


Volunteers at Panshanger Park busy with clearance of the invasive Himalayan Balsam