April Webb is a plant ecology intern at the Centre for Agroecology, Water and Resilience. She has worked practically within the horticultural industry and is actively involved in nature conservation and botanical surveying.

PlantAlert logo

Launched in July 2019, PlantAlert is a citizen science collaboration between the Botanical Society of Britain and Ireland (BSBI) and Coventry University designed to prevent future invasions of ornamental plants.

In contrast to the usual BSBI recording, Plant Alert is a survey of horticultural taxa proliferating in gardens. The aim is to identify potentially invasive plants before they become a problem in the wider environment. The project is based upon a pilot study conducted with support from the BSBI in 2016

There are often long delays, sometimes more than 100 years, from the introduction of species in gardens to the recognition of a problematic plant in the wild, making effective prevention strategies very difficult. Large numbers of species introduced into gardens over the last century   have therefore created an “invasion debt” of alien species that are already introduced and present in gardens. Furthermore, the invasion risk of these species could potentially be accelerated by climate change, resulting in plants previously not considered fully hardy to establish and spread. The challenge is to identify the potential future problematic plants out of this ever-increasing pool of about 70,000 ornamental plants available to gardeners.

Monkey Flower - Russell Biggs

Mimulus guttatus - Monkeyflower

The keen horticulturalists amongst us will know gardeners strive to provide the best achievable growing conditions for their plants and also control those that may otherwise dominate. Therefore, gardeners are among the first to notice traits that have also been recognised to contribute to successful invasions, such as vigorous growth, earlier germination, better survival of seedlings and longer flowering periods. Similarly, problems with removing plants no longer wanted could indicate potential control problems in cases where such plants establish outside gardens.

Crocrosmia spp.  Martie Swart

Crocosmia species


Plant Alert strives to engage gardeners to report plants in their own gardens or those of others, showing signs of invasiveness. In doing so people are contributing to the essential data required to understand and manage future invasive ornamental plants before they can cause negative impacts. With the 2020 gardening season starting now, we hope to increase the number of records received so far. BSBI members can play a crucial role in using and promoting the new recording tool.

Leycesteria formosa - Himalayan honeysuckle 

Data collected from Plant Alert will be used in risk assessments of species as well as to provide gardeners, nurseries, and land managers with advice on which plants could become difficult to manage. A key feature of Plant Alert is that it has been designed to be a permanent feature of BSBI recording efforts, with all records going into the BSBI database (labelled as Plant Alert records) where they will also be verified.

Houttuynia cordata

Houttuynia cordata - Heart-leaved hottuynia


 For more information, to contribute records, and view results, please go to

Plant Alert also has a twitter feed where you can keep track of the activities of the project, latest news, and potential species to look out for and report on @Plant_Alert 

Plant Alert is a long term BSBI and Coventry University recording project for ornamental plants spreading in gardens. If you have such plants in your garden, please  go to We would be grateful for you to recommend the project to your friends and neighbours. To get in touch with us email: [email protected]

Current top ornamental species reported.

 (August 2020) (excluding Japanese Knotweed & Himalayan Balsam)

Acanthus mollis

Houttuynia cordata

Akebia quinata

Leycesteria formosa

Allium triquetrum

Lamiastrum galeobdolon subsp. Argentatum

Anemone hupehensis x vitifolia = A. x hybrida

Pentaglottis sempervirens


Pilosella aurantiaca

Crassula helmsii

Sasa palmata


Symphoricarpos albus

Erigeron karvinskianus


Natural History Live by Katharina Dehnen-Schmutz & April Webb

On 8th April 2021 I delivered a virtual talk with Katharina Dehnen-Schmutz (Associate Professor in the Centre for Agroecology, Water and Resilience) title 'PlantAlert: Finding the Invasive Plants of the Future'. You can catch up with the talk through YouTube below.

The audience generated wordcloud of invasive plants reported in their gardens during the talk is displayed below.

Audience generated wordcloud of invasive species

Author: April Webb
Published:  11th August 2020
Last updated: 10th April 2021