TRIALS
Grown side by side
In the RHS hardy salvia trial, 70 selections grew at RHS Wisley from 2022 to 2024, three plants each, assessed by a 10-person judging panel.
See the numbersSome plants have to earn their trophy.
Since 1922 the Royal Horticultural Society has given its Award of Garden Merit to plants that perform under UK growing conditions. They win it in trial beds, judged over seasons, and they can lose it again.
- Grown in trial beds
- Judged by expert panels
- Reviewed, and sometimes dropped
- A label earned in the soil
THE SHORT ANSWER
Not a prize for looks,
a prize for staying power.
The award is meant to help gardeners choose reliable plants.
Three things decide it: trials, criteria and review.
HARDINESS
Rated for your winter
The award is cited together with a hardiness rating, from H1 for plants that need a heated glasshouse to H7 for the severest European winters.
Check a rating
REVIEW
Awards can be lost
In the 2024–2025 maincrop potato trial, six cultivars won a new award and three had their award withdrawn.
Why plants drop out
FOUR WAYS TO USE THE LABEL
Let the trial
do the homework.
The award is a shortcut to plants that have already been grown, watched and compared. It works best alongside what you know about your own garden.
Read the hardiness rating too
Check the H number beside the award and match it to the coldest spot the plant will live in.
Look for the trial report
RHS trial pages give judges' comments, heights and spreads, such as 80cm x 80cm for one award-winning salvia.
Check the right conditions
The award is for plants that are resilient in the right conditions. The salvia trial notes that good drainage is key for hardy salvias.
Treat the award as current, not forever
Awards are reviewed, so a plant on an old label may since have lost its place.
TWO NUMBERS WORTH KNOWING
Getting in is hard,
staying in is not automatic.
One figure from a whole-list review,
one from a single recent trial.
≈ 1,900
Plants that lost their award
In the 2012/13 review nearly 1,900 plants lost their award and more than 1,400 gained one, leaving 7,073 plants on the list.
THE 2012/13 REVIEW
11 of 70
New awards from 70 entries
Judges gave 11 new awards and reconfirmed 10 existing ones. No existing salvia award was lost in this trial.
HARDY SALVIA TRIAL · RHS
Awards were first set to be reviewed every 10 years from 1992; the review is now annual, so plants that become hard to buy or are bettered can be dropped.
A QUICK HARDINESS CHECK
Where will the
plant spend winter?
An award-winning plant still needs the right place. Pick a hardiness rating to see what it means. The bar shows how much cold the rating says the plant can take.
Ratings as listed alongside the RHS Recommended: Award of Garden Merit. Temperatures are the minimum each band covers.
HOW PLANTS LEAVE
Every hall of fame
needs a back door.
Plants can be put on a list for rescission if gardeners can no longer buy them, if better plants become available, if they suffer from pests or diseases, or if they are not uniform enough.
Trials keep the list fresh. When the RHS grew Aruncus for the first time at Royal Botanic Garden Edinburgh, in a 2024–2026 trial, the judges were asked to weigh invasiveness alongside flowers and foliage.
In conversation
Questions people ask
What is the Award of Garden Merit?
It is an award from the Royal Horticultural Society, given since 1922, for plants that perform well under UK growing conditions. It covers everything from annuals and perennials to shrubs, trees, fruit and vegetables.
What does a plant need to win it?
RHS trial pages say it goes only to plants that are healthy, excellent performers that are resilient in the right conditions, available to buy, reasonably resistant to common pests and diseases, and true to type.
How are plants judged?
Usually in trials. In the hardy salvia trial, three plants of each entry grew at RHS Wisley for three seasons, and a 10-person panel of experts met between June and September to assess them.
Can a plant lose the award?
Yes. Awards are reviewed, and plants can be dropped if they become unavailable, are bettered, suffer from pests or diseases or are not uniform. In the late maincrop potato trial, three cultivars had their award withdrawn.
Is it the same as the RHS Award of Merit?
No. The Award of Merit is a different RHS award, given to plants of great merit for exhibition, that is for show rather than for the garden.
Sources
Each figure on this page comes from the sources below.