Small amounts of funding is available through various sources, usually for equipment.

Wales

Keep Wales Tidy can help with small amounts of funding, as well as insurance and risk assessments. You are more likely to get funding if you have shown some commitment to the project up front, for example by mapping the areas infested by Himalayan balsam, contacting local landowners for access permission, and got a group of people together who are willing to volunteer their time.

Have a look at their website for more information, and to get contact details for the local office

In Pembrokeshire, if you are within the Pembrokeshire National Park boundaries, you can apply for a Little Green Grant up to a maximum of £1,500.
Have a look at: http://www.pavs.org.uk/funding/spsg/spsg.htm

England, Scotland and Ireland

Please let us know of sources of funding, so that others can benefit. You can also ask on the Himalayan Balsam discussion forum and see if anyone else can help.

General advice on funding

Applying for funding can be exhausting. Application forms may be long and not easy to understand, and you may have to hold a number of meetings of your local group to agree what you’re applying for, how and when. To save you some work, always phone the funding bodies before you start the process to make sure you fit the criteria. Often you won’t, and your effort will be wasted. It also helps to divide the project into subprojects, to show how you will use smaller amounts of funding, if less is available, and to make it generally easier to manage.

If you haven’t already formed a group, you will need to form one to apply for funding. You need a simple constitution and a bank account. Pembrokeshire Association of Voluntary Services have an excellent website, which will help you with setting up a group, applying for funding, etc. They also provide a good search function for funding on their website.
http://www.pavs.org.uk/

Your community (or town) council and county council may well pay a large proportion of the costs associated with Himalayan balsam control, for example if chemical weed killers are used. Find out how to contact your community or town council and go from there.

If you still feel you need more advice, why not ask the Himalayan Balsam discussion forum… there may well be people who have been in exactly the same situation as you, who can help.