More about the Perennial Directory

A plant directory for the new kind of perennial user

For those who are creating plantings that are broadly speaking naturalistic or ecological, and in some cases will be using entirely regionally-native species.

These kind of plantings use plants at higher densities that conventional herbaceous layout, and so competition between plants is more intense, and therefore it is more important to have knowledge about the ability of plants to project themselves in space, to potentially out-compete neighbours, and to reproduce themselves – in the parlance of ecological science, 'recruitment'.

However this kind of information, the temporal aspects of plants, is useful for any horticulture or design practitioner. Surely even the managers of traditional borders would like to know how their plants will live for or which is likely to seed itself to weed proportions?
Seeking such information in the existing paper and online literature is difficult, with one of the problems being that there is little appreciation of the basics of plant growth over time and a poor understanding of plant morphology.
Institutions that one might expect to know better, such as Britain's Royal Horticultural Society, clearly do not. The situation gets worse when we consider what goes on underground – there is so little reference to underground structures in the existing reference literature that one wonders whether any of these author ever dug anything up.
There is often confusion of basic terms like 'rhizome'. Images of underground structures are almost entirely absent from most sources.

The directory’s intention

My intention here is try to provide some information for these gaps in our understanding of plant growth over time. It is also my intention to share some of the material on basic plant ecology which I have included in workshops over the years in some introductory material. Much is the result of my own gardening over the years, observations in other gardens and the results of conversations and requests for information from other growers. 

21st century florilegium?

The title by the way, or at least the sub-title 'the 21st century florilegium', is a reference to what is still the go-to reference on perennials for many, Graham Stuart Thomas' Perennial Garden Plants, or The Modern Florilegium, first published in 1976. Stuart Thomas had a fine if rather patrician, turn of phrase and enormous plant knowledge – I quote from him occasionally, as 'GST' and refer to some of the more obscure plants he references, in the hope that they may still be obtained. 

Classification System

My classification system for perennials is based on the work of the late Prof. Aleksander Łukasiewicz, of the Botanic Garden of Poznán in Poland. His researches, supported by the artwork of Mrs. Fortunata Obrapalska, revolutionised my understanding of perennials.

What’s next?

Illustrations – I'm adding my own but also supplying links to that (mostly) tiny minority of images on the internet that actually show you plant habit.

Grasses – to be added by Christmas, I hope, as a separate section.

Biodiversity – it is very difficult to access information that is truly evidence-based. I'm looking at ways to do this. Will add a section soon.

Longer-term – more images of what goes on underground. And – a section on sub-shrubs.

Want to help? to collect or provide data or images? Please use the contact form to get in touch.

Acknowledgements

Thanks to Úna Scherer for drawings. Malgosia Kiedrzynska for Polish language support. Sachi Tanabe for website design. Gem for tech support.