Plant Heritage's Threatened Plants Programme provides a unique insight into the risks to our plant heritage
Of more than 133,000 cultivated plants that we have assessed, more than half are no longer reliably offered for sale in the UK. One in six are only recorded growing in one or two locations, or we have not found them at all.
Fluctuating fashions, urbanisation, changes in the nursery trade, loss of specialist knowledge, climate change and new pests and diseases all threaten the future of important cultivated plants. Can you help us to protect more plants, so we can all enjoy them in the future?
How does the Threatened Plants Programme work?
We track down what are called 'named cultivars' (such as Salvia 'Rodbaston Red') that are known to have been grown in the UK or Ireland at least 10 years ago, to find out where they are now. We assess the threat to these plants based on whether they are still available to buy, and where else they might be recorded as growing.
Nobody else is doing this research. We started in 2009 and add new data all the time, from a wide range of sources (find out more below). Sometimes we discover something we thought was lost, which is great, but too often we find that much loved plants have disappeared without a trace.
Pelargonium 'Sussex Delight', Threatened:Critical, Listed between 1996-2012
What can you do to help save rare plants?
Through National Plant Collections, our members and volunteers are safeguarding nearly 100,000 plants in a unique living library. Our Plant Guardian scheme helps us to discover, record and protect rare plants, whilst our free Plant Exchange helps to put these special plants back into circulation. With our network of local groups, we run regular events including plant fairs, talks and workshops to share green skills and celebrate hard to find plants.
You can help us protect even more plants for the future. Why not become a member, volunteer your time, or donate to support our work? Together, we can keep these plants thriving for everyone to enjoy.
Primula 'Fife Yellow' Threatened:Endangered. Listed between 1997-2008
C Stone
How is the research used?
This unique data helps National Collection holders as well as public and botanic gardens like the RHS and National Trust for Scotland to identify their rarest plants, so they can prioritise their conservation efforts. It is also a unique resource for people searching for particular cultivars. We can often pinpoint who last had a particular plant, or contact a garden still growing it to see if they can share propagating material.
What are the threats to our garden plants?
- Changing fashions: Changes in styles of planting and taste can cause groups of plants to go out of fashion. We do not want to lose the range of cultivars available for when they come back into fashion.
- Changes to the plant sales trade: Large sellers carry a limited range, prefer plants of a certain size and want them in flower when they are sold. This is why it is important to support specialist nurseries who carry a wider range of plants.
- Climate change: Drought, floods and storms all threaten the future of the UK's plant heritage. We are encouraging duplicate National Collections as a back up when plants are lost, and doing research that will help to identify more resilient varieties for the future.
- Pests and pathogens: global trade and travel increase the risk of pests and diseases being introduced to the UK e.g. box blight, ash dieback, agapanthus gall midge, and climate change is making this worse.
- Loss of key skills like propagation and plant recording: When plants are lost, the skills to look after them go too. Our National Collection holders are experts and we run regular workshops.
- Urbanisation: smaller gardens means less space to grow plants. People renting may also be nervous about investing in a temporary garden. Even if you do not have a garden, you can take part if our conservation schemes. 13,000 plants in the National Collections can be kept as houseplants, and anyone can become a Plant Guardian to look after just one or a few rare plants.
The methodology behind the Threatened Plants Programme (TPP)
The TPP focuses on named cultivars known to have been grown in the UK or Ireland for at least 10 years. We have records for more than 133,000 plants and we are adding to this dataset all the time.
We combine data from the Royal Horticultural Society's (RHS) Plant Finder (which shows the availability of plants through hundreds of UK nurseries, from 1987 to the present) with records from more than 2,000 locations, including the National Collections, Plant Exchange and Plant Guardian schemes and cultivar lists from botanic and historic gardens in the UK and Ireland. We are a small team, so this dataset is not comprehensive, but it gives an important insight into this problem and nobody else is doing this work.
If a cultivar is recording as growing or being sold in the UK or Ireland more than 10 years ago, but is no longer reliably found for sale through nurseries, it is considered Threatened in cultivation. Threatened plants are categorised as Critical in cultivation (not found alive), Endangered in cultivation (grown in only one or two locations), or Vulnerable in cultivation (three or more sites).
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