The lowdown on RHS Chelsea judging with James Alexander Sinclair

With the RHS Chelsea Flower Show fast approaching, we asked renowned RHS Judge, James Alexander Sinclair to share all about the art of judging show gardens.

James Alexander-Sinclair garden designer and RHS judge
credit: Chaz Oldham

One of the most experienced RHS judges, James Alexander-Sinclair has been judging show gardens since 2005. Over the years, he has played a key part in refining the process, to ensure the judging is more objective and transparent.

“The new judging process was introduced to make the process as transparent and easily understood as possible”, explains Alexander-Sinclair. “You judge the garden through the criteria which makes it both objective and fair.”

The criteria are updated every year to ensure relevance and sharpened when required. “Four years ago, the judging process was made stricter so that it took 30 points to score a gold medal, instead of the previous 28”, he added.

The excitement of RHS Chelsea knows no bounds, as despite his long judging reign, Alexander-Sinclair still looks forward to judging. “I do actually rather enjoy judging. I like the idea of it. Seeing new stuff. Knowing more about it. I like my fellow judges, though it can get quite lively occasionally as it can happen that radically disagree with someone. What is nice about it though, is that there is no resentment as you move on to the next garden. It’s always an interesting, lively debate”.

“We have to remember that when judging, you are judging someone’s 1.5 year’s worth of hard work. It needs to be done sensitively. You are judging their career. You need to be aware of all of those things and need to be respectful of the gardens that you are judging. But, likewise, the designers need to respect the judges and the judging process – which they have volunteered to be judged by as they chose to do the RHS show.”

Contrary to what some may perceive, judges aren’t looking to find fault, but rather as Alexander-Sinclair explained, “A judges’ job is to give the best medal they can”.

The RHS judges

Judges are selected by the RHS, but they are independent of the charity. They do not work for the RHS, and there is no influence from the RHS in the judging process.

Judges are recruited based on personal merit, or for added balance to ensure judging panels are representative of the industry, reflecting the right balance of designers, landscapers and horticultural experts. All are experienced at judging, having been through a training process, as ‘learner’ judges for several years, and only allowed to vote when fully accredited.

The choice of judge for a particular show is also very much down to whom is available from the judging pool, as many will be competing. At this year’s RHS Chelsea Flower Show for example; Tom Stuart-Smith, Ann-Marie Powell and Mark Gregory are participating in the show and for obvious reasons, are therefore excluded from judging.

A judging panel consists of seven, voting judges, with a moderator. The moderator does not have the vote, but can be called on to vote if one of the judges is unable to attend due to illness at the last minute. The moderator’s role is to ensure that all the gardens are given equal attention, assessed equally and consistently. Learner judges may often be part of the judging panel, but they observe only and do not cast a vote – until they have acquired the necessary experience.

“Ideally, all judges should be able to do all the jobs, and thus move around the various categories and shows”, says Sinclair. “For example at RHS Malvern, which was judged his week, I was part of the selection panel and for RHS Chelsea 2024, I was also part of the selection process, and will be moderator”, he added.

The number of judging panels is reflected in the number of garden categories at the shows, so RHS Chelsea has four panels of judges to judge the Show Gardens, Sanctuary & All About Plants Gardens, Houseplants and the Balcony & Container categories. For RHS Hampton Court Palace Garden Festival there are two judging panels, at RHS Malvern one and RHS Tatton, two.

In terms of hierarchy, the judges and assessors each have a Chair, who provide the designers with the judging feedback after the medals have been awarded. Alexander-Sinclair went on to explain that some people are better than others at giving feedback, and may therefore more likely presented with the Chair or Moderator roles.

The judging process

At the RHS Chelsea Flower Show everyone is striving for perfection, which is just what the judges are looking for. Importantly, show gardens at RHS flower shows are not in competition, come judging day. All participating designers have the same opportunity to winning a gold medal. They could all win gold, or none of them – all is possible.

The judging process breaks down into five stages; Selection, Assessment, Judging, Moderation and Feedback.


One could argue that the only true competitive aspect of the show is the actual selection process, where designers compete for the limited space to exhibit. Designers submit their brief for the garden which outlines, the description, purpose, function, key plants and features – which lays the foundations for what the judges will be expecting to see delivered come show time.

“The brief should be sensible. Don’t promise anything that you may not be able to deliver”, explains the judge.

Just as is the case for the judges, the selection committee represents all disciplines; landscape architect/garden designer, plant experts and landscapers. One or two of the judging panel will also be present on the selection panel.

Show gardens are selected for their creativity, innovation, originality, bold, brilliant ideas but also longevity and sustainability. Newly introduced, the selection criteria now also include a compulsory green audit, where gardens are assessed for their green credentials.

“The selection process is key, even more so in recent years, with the introduction of the environment audit to ensure the gardens are built in the most sustainable means possible and for the fact that all the gardens must have a home to go to after the show”, explains Alexander Sinclair


At the show, the judging posse splits to form an advanced guard – known as the assessor judges. Only this part of the judging team has contact with the designers.

On the Saturday before the show opens, the three assessors inspect/pre-judge the garden in terms of the execution of the brief in accordance with the expected standards of the judging criteria.

It’s at this crucial time that the designers have a final opportunity to relay any changes made during build to the brief, such as for example a different hedging choice. Otherwise, they may get marked down for that variation from the brief. On their garden inspection and discussions with the designers, the assessing judges will make their recommendations for the medals. Following the assessment, the assessors make their case for the medal recommendation to the rest of the judging panel – which may or may not be accepted.


On the Sunday morning, the judges come together with the moderator – whom all would have been around the gardens before.

At this stage of the proceedings, the judges are familiar with the gardens, especially as some of them will have also been involved in the selection process. The accessors present their case for each garden, the judges then insect the garden independently and come back as a group to discuss their findings and the assessors case. As a group the judges then go through all the criteria again in detail, under the watchful eye of the moderator to ensure consistency throughout the process.


Finally, the judges verdicts are submitted to a moderation process, intended to act as a kind of external examiner, ensuring that awards are consistent, and fine-tuning a decision where the judges are split. The moderator will listen to the judges’ vote and thinking to ensure consistency.

At this stage, the merited medal will then be confirmed.


Judges’ feedback to the designers on their awarded medal will be balanced, honest and devoid of personal opinions. “Feedback is just explaining to the designer where they did well, what went wrong, where they can improve etc. So that they can do better for the next time”, explains Alexander-Sinclair.

Feedback can sometime be “feisty”, he says. “The inevitable truth is that any judging is deemed marvellous if you win a gold medal and entirely corrupt if you win a bronze. You have knowingly entered your garden into this system. You have gone through it and if your garden is for wanting based on these criteria – which you are fully aware of when you started, it’s not because the judges or the RHS are against you”.

Once the medals are presented, there is no turning back, however lively the feedback process. “There is no VAR in show garden judging”, he says.

The judging criteria

There are nine criteria show gardens need to adhere to, which are the same for all categories, across all the RHS Shows.

The criteria enable the judges to be objective in their judging, especially because, how ever large the pool of judges may be, they will be familiar with each other, can even be close friends and may work together in the industry. “That is why we have the criteria and everyone knows that. We all know each other and are fond of each other, but personalities, how ever lovely have nothing to do with it”, explains the judge.

Available for all to read on the RHS website to ensure complete transparency, the criteria are as follows:

  • Realisation of the brief
  • Ambition – the degree to which it shows flair, originality, impact & theatre
  • Overall Impression – degree of finish, attention to detail, dressing, styling, choice of materials
  • Design & layout – degree to which the garden demonstrates proportionality, scale, ergonomics, comfort and design generosity
  • Design & composition – degree to waging the garden demonstrates grasp of 3D spatial design, sequential views and framing
  • Construction – quality of build and degree of finish, craftsmanship, flair etc..
  • Planting design – visual impact in terms of texture, colour, composition, texture and form
  • Planting associations – horticultural accuracy, plant relevance and cultural requirements
  • Planting implementation – plant quality, health & appropriate density

Best in Show

The most competitive element of the show is the coveted ‘Best in Show’ Award. The top scoring garden will be validated with Best in Show, but if there is a tie, the judges will have a secret vote to determine the overall winner. “This is the only time in the judging process when judges vote from the heart”, explains Sinclair.

We await the results with bated breath, and wish the designers – across all the shows the very best of luck throughout the process…