Rhubarb (Rheum x hybridum) collections have been held at RHS Garden Wisley since 1904, providing a basis for the only non-ornamental National Plant Collection currently held by the RHS. The collection now includes over 100 cultivars, including some of historical interest.
The entire collection is catalogued in the RHS Horticultural Database, and steady progress is being made in creating herbarium specimens. In addition, a full photographic record of the collection is being built up, together with descriptions and drawings of stem cross-sections. This is providing valuable information to help in the identification of cultivars.
Close liaison is maintained with the other National Plant Collection of rhubarb, held by RHS Garden Harlow Carr in Yorkshire, and exchanges of material benefit both collections.
The collection at Harlow Carr of over 130 taxa includes wild Asian species, medicinal and decorative species like Rheum palmatum and Victorian culinary favourites like 'Prince Albert' and 'Victoria'. It also includes newer introductions, such as those bred at Stockbridge House research station near Selby, Yorkshire. The National Rhubarb Collection will conserve a part of the West Riding's vanishing heritage.