A modern reference to temperate woody plants
The site
Trees and Shrubs Online is the International Dendrology Society’s ambitious project to create a modern, web-based encyclopaedia of woody plants hardy in the temperate parts of the world. The website was launched on a core of data formed from the full text of Bean’s Trees and Shrubs Hardy in the British Isles and of New Trees, making these seminal texts freely available to anyone, anywhere with an internet connection.
The long-term aim of the project is to renew these texts entirely, creating a fresh body of information for the twenty-first century that will make this the pre-eminent resource for anyone interested in trees and shrubs. The day to day project management, including editorial oversight of all new text, is the responsibility of the Editorial Team.
The text
Currently, the bulk of the text is derived from two sources. The 'Bean' text is from the Eighth Edition, the last to be published, which appeared in four volumes during the 1970s, along with the Supplement, published in 1988. New Trees was published in 2009 and sought to cover all the new introductions to cultivation from the period from the Eighth Edition to c. 2005.
Bringing all entries up to date is a large, complex, and long-term project. Some major genera, such as Rhododendron and Quercus, will need to be published incrementally, while others will be revised in full as funding becomes available. Many groups have already been revised (see Completed Groups), and an international team of authors is constantly at work preparing new entries.
The IDS
Trees and Shrubs Online has been made possible by the International Dendrology Society, a truly international organisation with c. 1500 members in 50 countries. Since its inception the IDS has been dedicated to its charitable aim of advancing the knowledge of woody plants around the world. The idea for TSO was born out of the success of New Trees, itself an IDS project, and since the website’s launch the IDS has worked to raise funds to support the project’s ongoing work.
These efforts are now being rewarded by the tens of thousands of unique visits to TSO every month, from countries all around the world, and everyone involved in TSO looks forward to seeing these figures increase further.
Sponsorship
May 2025: Trees and Shrubs Online relies on generous donations to meet its core costs and sponsorship to enable new text to be researched, written, edited and published. The project is indebted to the many individuals, organisations and charities that have contributed generously to our aim of disseminating new, high-quality information for free, for everyone.
Thanks to the great generosity of several private donors we were able to increase editorial capacity in 2024, and in early 2025 we recruited for a new position of staff author, welcoming two new colleagues to the TSO team who took on this new role in a job-share arrangement from the beginning of March.
Despite this fantastic progress we continue to rely heavily on new sponsorships to maintain momentum. We would be delighted to hear from anybody interested in supporting TSO’s ongoing work. To find out how you can help please write to editor@treesandshrubsonline.org
Recent publications
May 2025: We are delighted to announce that a new account of Hydrangea has been published ahead of the Chelsea Flower Show. We consider this monumental work by Dr Julian Sutton to be among the most important accounts of this genus ever to have been produced. It will surely become the standard work on the subject for years to come, treating 73 woody species, 9 lower taxa, and over 570 of the most important cultivars, all illustrated by over 1300 images.
This milestone publication follows on from other new revisions to appear in recent months. There has been a coincidental focus on the southern hemisphere, with new accounts of the hardy Winteraceae (Drimys, Pseudowintera, Tasmannia) following on from new text for Azara which appeared in April. North of the equator new accounts of Loropetalum and Tetrapanax provide much needed information on these popular genera that have been hitherto poorly served by horticultural literature.
A list of all groups fully updated so far may be found on the Completed Groups page; this is updated whenever a new account is published.