UPDATE: As of October 11, 2018, this register of cultivars remains valid and current for genera H to Z only. For Abelia to Gymnocladus cultivars please download

Hardy herbaceous perennials make up a major part of our gardens in the world. For mostly political reasons, there is no formal process for cataloging or registe

Hatch's Cultivars of Woody Plants has been developed over 35 years by leading horticultural taxonomist Larry Hatch and now covers more than 2100 pages. It is th

This 114-page volume covers Rhamnella, Rhamnus, Rhapiolepis, Rhododendron including deciduous and evergreen azaleas, Rhus, Ribes, Robinia, Rosmarinus (over 200

This volume covers Pseudotsuga (douglas-fir), 93 different Sciadopitys, 44 Sequoia, 85 Sequoiadendron, and a shocking 353 cultivars of Taxus. This recent revisi