More than just a symbol of Christmas

Mistletoe has an air of Christmas magic, but it is, in fact, a parasite with a fascinating relationship with trees. European mistletoe (Viscum album) grows in green clumps on various trees across the UK, especially noticeable in winter once trees have lost their leaves. While mistletoe can sometimes harm the trees it grows on, it can also benefit other species, like winter birds that eat its berries.

Mistletoe is thought to be spreading in the UK, but we don’t know where and why. Exciting new research aims to gather data and forecast the future of this intriguing and important plant.


This new citizen science app has been launched to help us understand how abundant mistletoe is in the UK. The app enables anyone to report mistletoe sightings in the UK; it involves a simple process of uploading a photo, estimating the number of clumps visible in a tree and recording where it was seen. The public’s involvement in this important pilot project will help to shape and improve the future of this research.


Everyone is invited to get involved! You don’t need any prior knowledge or expertise, just a keen eye for a clump of mistletoe.


Anywhere in the UK! During a regular walk or when visiting a new area, just have a look at trees as you pass to see if there are any mistletoe clumps. Make sure you’re in a suitable location to take a photo and use the app to send in the record.


Mistletoe is easiest to spot in winter when trees have lost their leaves, so the survey will run from November 2023 until the end of February 2024. The data will then be analysed and we will provide updates.

Accessing the survey

  1. Download the Survey123 app from the App Store or Google Play
  2. Download the MistleGO! survey via the link above or the QR code
  3. Open the app and click “Continue without signing in”
  4. Click on the MistleGO! survey and start collecting your record!

You can also upload pictures you’ve taken via the web version, but make sure to set your location to where you spotted the mistletoe!

MistleGO! Online Talk

View Ollie Spacey’s online presentation on the MistleGo! app and why mistletoe is an under-researched but crucial species.

Stay in touch about this research

If you have any questions or would like to be kept updated about this project, please email our Science & Research team at For media enquiries, contact

Researcher profile: Ollie Spacey

Ollie is studying his DPhil (PhD) at the University of Oxford, focusing on the biology of mistletoe. He is supported by The Tree Council and the MistleGO app has been developed in collaboration with Fera Science. He is particularly interested in how mistletoe interacts with its host trees and what this can tell us about parasitism more broadly.