Invasive Non-Native Species (INNS) week will take place between 12th May and 18th May. It is an annual initiative that aims to raise awareness about invasive non-native species (INNS) and promote actions to prevent their spread.
Roots of the Problem
What are invasive plant species and why is it important to remove them?
Invasive non-native species (INNS) like Japanese Knotweed and Himalayan Balsam pose significant threats to our local ecosystems. These plants outcompete native species, disrupt habitats, and contribute to flooding in Calderdale. Use these identification sheets to familiarise yourself with invasive species.
How do they get into woodlands and green spaces?
Invasive species reach woodlands and green spaces through natural means like wind or water, but mostly via human activity—carried on shoes, clothes, or bike tires.
How can you help?
Check, Clean, Dry
Whenever you’re out in the countryside, remember to Check, Clean, Dry to help stop the spread of invasive plants and animals on land and in water. Yorkshire Water has set up dedicated boot cleaning stations at strategic locations throughout Calderdale to help prevent the spread of non-native species and reduce human-driven transfer.
Additionally, Calderdale Council will be installing a new boot cleaning station at Jerusalem Farm by the end of May.
This video from Yorkshire Water and Yorkshire Wildlife Trust gives more information on the invasives problem in Yorkshire and how to affectively check, clean, dry your footwear to stop the spread.
Eyes on the ground
The most impactful way you can help is by reporting sightings of invasive species on the INNS Mapper app and website. This is especially important for Japanese knotweed and Giant hogweed, as they require professional treatment and should not be removed by individuals.
Volunteer at Hardcastle Crags
Join Slow the Flow for balsam bashing on June 1st, July 6th, August 3rd.
• Meet at Midgehole car park for 9.30am (please make your own way to Hardcastle Crags)
• There will be a 10 – 15 minute walk to get to the activity
• Finish by 1.00pm
Must have items:
• Sturdy footwear
• Long sleeved clothing due to forest undergrowth and bugs
• Drink and snack
Please note:
Under 18s must be accompanied by a parent/guardian.
Bash the balsam
Himalayan Balsam can be easily removed with a few simple steps. Here are five fast facts:
1. Shallow roots make it easy to pull out.
2. Snap the stems to prevent regrowth.
3. Dispose of the plants responsibly.
4. Join local bashing events.
5. Encourage others to participate. #BalsamBashing #Bashthebalsam
The Yorkshire Invasive Species Forum and Yorkshire Wildlife Trust have produced a guide to help you pull Himalayan balsam safely.
INNS Week webinars
The INNS and Biosecurity team at the Environment Agency is excited to announce a series of informative webinars during INNS Week. These sessions are designed to educate the public on various aspects of invasive species and biosecurity. Everyone is welcome to join, and registration is simple through the provided links. Don’t miss this opportunity to learn from experts in the field!
Webinar Schedule:
Introduction to invasive species and biosecurity
- Date: Monday, 12th
- Time: 11:00 – 12:00
- Description: This session will provide an overview of invasive species and the importance of biosecurity measures. Perfect for anyone looking to understand the basics and implications of invasive species.
- Registration Link: Microsoft Virtual Events Powered by Teams
Non-native species inspectorate – enforcing the law
- Date: Wednesday, 14th
- Time: 11:00 – 12:00
- Description: Learn about the legal aspects of managing non-native species and the role of the inspectorate in enforcing these laws. This webinar is ideal for those interested in the regulatory side of biosecurity.
- Registration Link: Microsoft Virtual Events Powered by Teams
Floating pennywort – challenges and opportunities
- Date: Thursday, 15th
- Time: 10:00 – 11:00
- Description: Discover the challenges posed by Floating Pennywort and explore potential opportunities for its management. This session is geared towards those looking for practical solutions and innovative approaches.
- Registration Link: Microsoft Virtual Events Powered by Teams

Four close-up photos of Himalayan balsam flowers.