A team of 10 independent assessors is used to evaluate each cultivar. Equal numbers of male and female assessors are used, and these are drawn from all forms of gardening such as garden designers and advisors, to gardeners from domestic and public gardens.

Fragrance is assessed independently of the aforementioned -
it is assessed twice per year by 4 people.

In the first year of trial, the first assessments are not made until the second week of December and thereafter at 4 weekly intervals throughout the growing season to early May - hence 6 assessments are made in the first year.

In the second year of trial, assessments commence at the start of the growing season (late October) and again are taken at 4 weekly intervals until the end of the growing season in early May - hence 8 assessments are completed in the second year.

A team of volunteers removes spent flowers after each assessment (4 weekly).

The following assessment criteria is used:

1. Habit (first impressions). 30 marks

a. Attractive, well balanced specimen to suit the type of plant, be it a climber, bush, shrub, miniature or ground cover.
b. Plant should be well clothed with foliage as typical of its type (climber, bush, shrub, etc.) and flowers and/or buds or hips nicely presented to view as typical of type.

2. Health. (Foliage and flowers) 20 marks

a. Health and vigour. Refers to ready production of new shoots and robustness appropriate to the type of plant.
b. Hardiness. Tolerance to weather throughout the season (eg: heat, wind, rain).

3. Flowering. 30 marks

a. Beauty of bloom/buds and/or cluster. Symmetry of bloom through bud stage to fully open, attractive, well balanced sprays or clusters.
b. Abundance of flowering – blooms and/or buds. Attractive display well placed over plant as typical of type, ability to repeat flower or continuous flowering.

4. Pest and disease tolerance. 20 marks

a. Fungal diseases – Evidence of mildew, Blackspot and/or rust.
b. Pest tolerance – Aphids, spider mite, grubs.

5. Fragrance. 10 marks

a. Strength.
b. Sweetness.

The score is then converted to a percentage (%) for the purpose of determining the awards.