David & Charles PLC · Hardy Plant Society · Timber Press, Incorporated
| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Penstemons | 978-0-901687-23-4 (0-901687-23-5) | 2006 | |
| The Gardener's Guide to Growing Penstemons | 978-0-7153-0550-8 (0-7153-0550-6) | 1998 | Peter James |
| The Gardener's Guide to Growing Penstemons | 978-0-88192-424-4 (0-88192-424-5) | 1998 | " |