Garden Climate Assessment Tool

The Future of National Gardens Group – a partnership of leading horticultural, heritage and landscape organisations – invites professional gardeners, horticulturists and designers to trial a new digital tool being developed to help prepare UK gardens for climate change and share their feedback to shape the tool’s development.

The Garden Climate Assessment Tool (GCAT) is a new free-to-use risk assessment tool under development for horticulturists that explores how suitable plants may be for the UK’s future climate. Helping professionals from the garden and landscape sectors make more informed decisions about the plants they grow and care for, the tool should be used alongside gardening expertise and other information about the plant and where it grows.

What GCAT can be used for?

GCAT can support users making climate-resilient planting choices, help to identify potential plants at risk, as well as opportunities to trial new plants in a changing climate, and inform the care and management of important plant collections that may be at risk.

How GCAT works?

GCAT assesses how well suited a particular plant, or list of plants, is to the climate of a particular place. It does this by comparing two things: the climate of the selected place, now and under future scenarios, with the range of climates the selected plant has been recorded growing in, to generate a climate risk score for the plant’s suitability at that place.

Building on Botanic Gardens Conservation International’s Climate Assessment Tool, GCAT has been adapted for UK gardens and covers a wider range of plant forms, including cultivated varieties (cultivars). It allows users to explore multiple climate factors including average annual temperature, winter cold and how dry a climate is.

What GCAT doesn’t do?

GCAT looks at how well suited plants are to a climate over the long term. It does not predict how well a plant will perform. The performance of a plant also depends on local factors, including soil type, soil health, drainage, irrigation, microclimate and extreme weather events, as well as genetic differences between plants. The tool should be used alongside local knowledge, gardening expertise and other information about the plant and where it grows.

Quick start to GCAT

1. Which plant? Start typing the plant’s scientific (Latin) name and select from a dropdown list of cultivated plant names
2. Which place? Start typing the place name and select from a dropdown list of UK cities, towns and gardens
3. Click the ‘Assess’ button
4. A summary of the climate suitability of the plant at the selected place will be shown for current and future climates
5. Leave your feedback in the pop-out survey on the right side of the screen

Entering a plant

Begin typing the plant’s scientific name and choose from the suggestions. If multiple results appear, choose the entry that best matches the plant you are looking for. Scientific (Latin) names are used as common names can refer to multiple different plants, and different common names can be used for the same plant.

Hybrids
For hybrid plants, GCAT will convert the letter ‘x’ into a hybrid symbol (‘×’).

Synonyms and name changes
GCAT contains a list of plant synonyms (older scientific names). If you choose a synonym, results will be shown using the currently accepted name.

Risk scores

GCAT calculates a climate risk score (-9 to 9) based on how widely the plant is known to occur in climates comparable to that of the selected place. Risk scores are grouped as either negligible, low, medium or high. Lower scores indicate a lower climate risk, and with the right conditions, microclimate and care, these plants could be good choices for your area.

Negative scores indicate the selected place is colder or wetter than the plant’s known climate range, and positive scores indicate the place is warmer or drier.

GCAT uses a range of climate parameters to assess the climate suitability of plants. These are derived from published bioclimatic variables that have been shown to be useful predictors of plant distributions and are widely available for baseline and future climate scenarios. The default assessment uses three climate parameters to give an overview of climate suitability:

• Mean annual temperature
• Mean minimum temperature of the coldest month
• Climate water deficit

It is also possible to select additional climate parameters of interest under ‘Advanced settings’:

• Mean annual precipitation
• Climate moisture index
• Vapour pressure deficit

GCAT assesses whether a plant is known to occur in climates similar to the selected place for various climate scenarios, including historic climate, current climate and a range of future projected climates.

Current (2025 estimate)
An estimated climate for 2025 calculated using baseline (1970–2000) climate data and moderate climate projections.

Baseline (1970–2000 average) – advanced settings
A baseline climate calculated using average data from over a 30 year period (1970–2000) to account for variation in weather from year to year. This is the reference period most climate projection models use.

Historic (1850 estimate) – advanced settings
An estimated climate for 1850 before human activity and urban heat widely impacted the climate. This is useful for understanding the climate of historic plantings and the climate in which many native plant communities were formed.

Low emissions by 2050
An optimistic climate scenario predicted for 2050 (using the SSP1-2.6 IPCC scenario), assuming that steps have been taken to limit global emissions.

Moderate emissions by 2070
A moderate emissions scenario predicted for 2070 (using the SSP2-4.5 IPCC scenario). This is considered the most likely scenario that plants we choose today will experience in their lifetimes.

High emissions by 2090
A high emissions scenario predicted for 2090 (using the SSP3-7.0 IPCC scenario), assuming that global emissions have not been limited and continue to rise. This time period is still within the lifespan of many trees and other long-lived plants.

GCAT uses a range of biodiversity databases to determine where plants are known to occur. These databases focus on either the natural or naturalised ranges of plants (e.g. the Global Biodiversity Information Facility) or cultivated ranges (e.g. PlantSearch – data from botanic garden living collections managed by Botanic Gardens Conservation International). From the location of each plant observation in these databases, the known climate of each plant can be determined using global climate datasets and climate projections.

The following data sources are used by GCAT, with the option to choose which databases the assessment uses under ‘Advanced settings’:

• GBIF Rural – Observations from the Global Biodiversity Information Facility, excluding records in urban areas and in botanic garden living collections. This dataset most closely represents the natural or naturalised range of a plant. GBIF data does not include cultivated plants (e.g. cultivars).
• GBIF Urban – GBIF records from urban areas, which are more likely to include cultivated plant records, and more likely to experience urban heat.
• GBIF Living – GBIF records from botanic garden living collections. These plants are more likely to benefit from manual interventions such as irrigation.
• PlantSearch – Records from botanic garden living collections managed by Botanic Gardens Conservation International (BGCI). This dataset includes cultivated plants.
• Cultivated urban and home garden records (CULTPLANTS) – This dataset includes published inventories of cultivated plants excluding botanic gardens.

Occurrence data

GCAT relies on the documented observations of plants. This occurrence data can contain biases, for example, more records in populated areas or near infrastructure, and may be incomplete for under-surveyed and isolated areas and for cultivated plants, particularly those that are new or in limited cultivation. The greater the number of occurrence records for each plant, the better the assessment will be. For plants with limited data, such as rare or threatened species or cultivars with few observation records, the known climate distribution is unlikely to represent the full extent of climate suitability.

Climate niche

All plants have a climate niche in which they can occur. The part of the niche where a plant is known to occur is called its realised niche. The full climate range a plant can tolerate and survive in is called its fundamental niche. For many plants the fundamental niche is larger than the realised niche. For example, the natural distribution of a plant may be restricted by geographic barriers to dispersal, competition, pollination interactions and pests and diseases, narrowing the realised niche and not fully representing the climate range of the plant.