If you would like to have a plant or pest identified, or a plant in your garden is diseased or dying, RHS Gardening Advice may be able to help. A good sample helps the scientific staff in their work. Please follow these guidelines for sending samples.
Include as much information as possible, such as:
- the age, planting or sowing date
- the plant size and overall appearance, since samples deteriorate in transit
- if diseased, the distribution of symptoms and when they were first seen
- notes on the planting site (e.g. in a greenhouse, a pot outside, or in open ground, in sheltered, windy, damp, dry, shady or sunny conditions, on heavy or sandy soil).
- details of watering are useful
- notes of any chemicals or fertilisers that have been applied, and soil pH (please note RHS Gardening Advice and the RHS soil analysis service are unable to test for chemicals or other contaminants in soil).
For email enquiries, clear digital images embedded or as jpeg attachments are helpful, but please note we are unable to access memory sticks, CDs or public sharing websites.
Specimens should be placed individually in dry polythene bags, not "cling film", clearly labelled, and packed in a crush-proof box or padded envelope.
For disease diagnosis, wrap the specimen in dry absorbent paper such as kitchen towel, and then in a polythene bag.
For plant or pest identification, place directly in a polythene bag without wrapping. Do not wrap the specimen in wet paper.
Send a good-sized specimen with typical leaves, buds and if possible flowers, in good condition. Specimens should preferably be fresh, or carefully pressed with notes of the colours when fresh. Clear photographs can also be helpful.
Please note we do not:
- Identify more than five plants samples at a time
- Identify plants down to cultivar level
- Identify wildflowers from the countryside (i.e. outside gardens) or those photographed on overseas holidays
- Identify plants from seed collected abroad that contravenes quarantine restrictions or CITES
- Identify fruit (but see public fruit identification days)
- Identify seeds, roots, bark, wood samples or non-pathogenic mushrooms
In case of suspected poisoning by a plant, seek medical advice from your GP or vet.
Enclose samples of both healthy and unhealthy material, ideally one shoot or twig. If the plant is small, it is best to send the entire specimen. Place the root system with adhering soil inside a dry polythene bag secured at the base of the plant. Then place the whole specimen inside another bag.
Please note: we do not examine soil samples for diseases. Do not send soil samples unless specifically requested.
Plant viruses: Testing is not available due to the specialised nature of the diagnosis. This service is available to gardeners from the Plant Clinic at FERA (The Food and Environmental Research Agency).
Leaf symptoms may be the result of root diseases. It is helpful to enclose root samples taken from four points equally spaced around the plant base. Include a range of root thicknesses and healthy and unhealthy samples. Do not wash soil from the roots.
Samples should be at least 5 cm (2 in) square and 2.5 cm (1 in) thick taken from the junction of healthy and unhealthy areas.
These should not be sent in a polythene bag, but wrapped in paper towel or newspaper. We only identify fungi that are harmful to plants. We do not comment on edibility.
For non-urgent fungi enquiries please contact RBG Kew.
Pests and other animal identifications
Where possible send live samples with their food plant. Place them in a dry polythene bag in a stout container. Soil-dwelling animals should be sent with some moist soil. Always give details of the circumstances in which the animal was found.
Please note: sometimes pests and organisms that cause disease (pathogens) currently not established in the UK are detected as a result of samples sent to the RHS Advisory Service. Individuals and organizations, such as the RHS, are encouraged to report suspected new problems.
Please be aware that when we suspect that a pest or pathogen may be new to Britain, we will report this to the Plant Health and Seeds Inspectorate, giving your contact details and possibly other information that you have given us so that the matter can be investigated by the appropriate authority.
See information on some non-native pests and diseases, some of which have already been found in Britain.
Samples from abroad
We ask that no samples of insect, plant, soils or any other biological materials be sent to us from abroad, except the Republic of Ireland, because of the associated risk of introducing exotic pests and diseases into the UK. It is not possible to be certain that samples are free of potential problems even if they appear healthy. Overseas members are very welcome to send photographs instead, ideally accompanied by a covering note with as much detail as possible. Where doubt exists please contact RHS Gardening Advice for clarification.
Our web page on importing and exporting plants has a lot of useful information for those considering bringing plant material back from abroad.
A note on Japanese knotweed & giant hogweed
Members wishing to confirm the identity of suspected Japanese knotweed or giant hogweed are kindly requested to send photographs only, not samples. Japanese knotweed & giant hogweed are classed as ‘controlled waste’ in the UK and cannot be readily disposed of by the RHS.
See more on Japanese knotweed & giant hogweed.
Where to send your sample
Send to RHS Gardening Advice, RHS Garden Wisley, Woking, Surrey GU23 6QB by first-class mail to arrive early in the week, to reduce deterioration of the sample. Please quote your membership number, and include either a postcode or email address. We would be grateful if you could ensure the correct stamps are used for the weight and thickness of the package.
For non-members wishing to use the service please first join the RHS before sending in samples or enquiries.