What is a herbarium?

Most specimens in a herbarium are pressed, dried plants. These pressed specimens are mounted on sheets of card and stored in flat folders in banks of cupboards following a logical sequence for easy referral.

This sequence can either be arranged alphabetically, like an index, or by similarity, placing those plants that are most closely related beside each other.

Other specimens may be dried large fruiting bodies, pieces of wood or bark, seeds or material stored in spirit to preserve more delicate three-dimensional structures. A herbarium also keeps document records about the specimens - where, when and who collected them.

Herbaria are used by botanists for the identification and classification of plants. They preserve most of the important features of a plant, allowing botanists to carry out research on the plants without needing to see a living specimen. As the plant is usually preserved when flowering or fruiting, the botanists can examine the most important features irrespective of the time of the year.

They also provide a historical record of what was growing in a particular place at a particular time. Many historic collections in herbaria now record plants no longer living in the location they were collected from. For cultivated plants, these records will give a latest date for when a particular plant was first grown.

Collections in the RHS Herbarium

RHS Herbarium history

The RHS Herbarium - situated at RHS Garden Wisley - is the largest herbarium dedicated to ornamental plants in the UK and dates from 1917, although the oldest specimen is from 1731.

More on the history of the herbarium

RHS specimen database

The RHS Herbarium is in the process of being databased so that the information is more easily accessible to members and the public. An initial study from 2004-2006 allowed all the specimens in the main herbarium to be catalogued to a basic level. This recorded the name, the date it was collected and whether the plant was from the wild or cultivation.

The database currently contains records for more than 60,000 herbarium specimens and almost 40,000 slides, photographs and paintings.

More on the database and search for specimens

Nomenclature standards

Nomenclatural standards help fix the name of cultivars by preserving a sample or an image of a plant known to have come from the breeder of that plant. The RHS Herbarium is one of the few herbaria internationally that is actively collecting standard specimens.

Learn about and search for nomenclature standards

Send in a herbarium sample

The RHS Herbarium welcomes material of plants in cultivation that are new or unusual.

More on sending a sample to the RHS Herbarium

Material can either be pressed before sending or material can be sent in fresh and it can be processed here.

Press and collect your own herbarium specimen

National Plant Collections

One of the requirements of a National Plant Collection holder is to make a collection of herbarium specimens from their living collections. The RHS Herbarium works in conjunction with plant collection holders by offering advice and knowledge for the preparation and archiving of the specimens.

More on National Plant Collections


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The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.