Choosing Conservation Plants
Plants are chosen for inclusion in the Scheme under specific criteria to make selection as objective as possible. We developed the revised criteria from international criteria for endangered wild plants but modified them to make them more appropriate for fulfilling the aims of the HPS Scheme.
The Scheme uses a points system with a proposed plant scoring up to a maximum of 10 points under the general headings:-
Resilience (up to 3 points) eg
Grows well consistently in
a range of areas in the country;
a range of soil types;
areas with winter temperatures of -10°C or less;
areas with late frosts;
exposed positions – high altitude, salt, winds;
regular periods of wet or drought.
is resistant to pests and diseases.
Garden value (up to 3 points) eg
has a long flowering period;
has a good ratio of flowers to foliage;
has interesting foliage and/or fruit and/or scent;
has a ’well behaved’ habit i.e. doesn’t need staking or increases at a moderate rate rather than rapid colonization of the whole border;
attracts beneficial pollinating insects.
Historical significance/breeding/provenance (up to 2 points) eg The plant is:
a distinctive break from other cultivars;
an important parent in the breeding line;
one with an unusual trait which could be valuable for future breeding.
Horticultural awards (up to 1 point) eg
the plant has an RHS Award of Garden Merit or other significant national or international award.
Difficulty of propagation (up to 1 point if difficult)
the plant is slow to bulk up or difficult to propagate.
A plant with five or more points and fewer than four entries in the Plant Finder may then be considered for entry into the scheme and reviewed to make sure it meets the criteria.