International:

• Award of Garden Merit (AGM): a prestigious recognition bestowed by the Royal Horticultural Society (RHS) in the UK to plants that demonstrate outstanding performance and reliability in UK growing conditions. It serves as a valuable marker of quality for gardeners, helping them choose reliable and successful plants for their gardens.
• Perennial Plant of the Year (PPA): Chosen by the Perennial Plant Association in North America, this award recognizes a perennial for its overall excellence in terms of low maintenance, adaptability, long bloom season, and multiple garden uses.
• All-America Selections (AAS): This program evaluates new cultivars across various plant categories, including perennials, based on specific performance criteria within various regions.

Regional:

• Great Plant Picks (GPP): Several regions in the United States and Canada have GPP programs that assess plants for regional suitability and pest/disease resistance.
• Proven Winners® Perennial of the Year: This award program highlights high-performing perennials that thrive in diverse growing conditions across North America.

Specific Plant Category Awards:

• Daylily of the Year (American Hemerocallis Society): Recognizes outstanding daylilies based on various characteristics like flower form, color, and habit.
• Hosta of the Year (American Hosta Society): Celebrates exceptional hostas for their foliage features, growth habit, and overall garden impact.
• Grass of the Year (North American Native Plant Society): Recognizes native grasses for their ecological value and ornamental appeal.

Additional Awards:

• Royal Horticultural Society (RHS) Plant of Merit (POM): A similar recognition to the AGM, awarded to plants demonstrating excellent performance in UK gardens.
• International Bulb Trials: Evaluate and recognize outstanding bulb varieties, including perennials like flowering onions and alliums.

The Award of Garden Merit (AGM) is a prestigious recognition bestowed by the Royal Horticultural Society (RHS) in the UK to plants that demonstrate outstanding performance and reliability in UK growing conditions. It serves as a valuable marker of quality for gardeners, helping them choose reliable and successful plants for their gardens.

Here's a breakdown of the key aspects of the AGM:

What it signifies:

Excellent performance: The plant thrives and performs well under typical UK gardening conditions, without requiring excessive care or attention.

Availability: The plant is readily available from reputable nurseries and garden centers.

Good constitution: The plant possesses inherent strength and resilience, showing resistance to diseases and pests.

Stable form and color: The plant retains its expected characteristics, ensuring consistency and predictability in your garden.

Reasonably resistant to pests and diseases: While no plant is entirely immune, AGM-winning plants exhibit a lower susceptibility to common garden problems.

Awarding process:

Plants undergo rigorous trials at RHS gardens or through expert observation in specialist collections.

Trials typically last for one or more years, depending on the plant type.

A panel of horticultural experts evaluates the plants based on the aforementioned criteria.

Awards are only given to plants that meet all the required standards.

Benefits for gardeners:

Provides assurance of a plant's suitability and performance in UK gardens.

Helps save time and money by avoiding plants that might struggle or perform poorly.

Introduces you to a curated selection of reliable and high-quality plants.

Offers a valuable reference point when planning and selecting plants for your garden.

Additional resources:

RHS Award of Garden Merit website: https://www.rhs.org.uk/plants/trials-awards/award-of-garden-merit

Lists of AGM-winning plants: https://www.rhs.org.uk/plants/trials-awards/award-of-garden-merit

Wikipedia article on the Award of Garden Merit: https://en.wikipedia.org/wiki/Award_of_Garden_Merit

There are many groundcover perennial plants that have won the Award of Garden Merit (AGM) by the Royal Horticultural Society (RHS). Here are a few examples:

Hostas: There are over 90 hostas that have been awarded the AGM. They are popular shade-loving plants with a wide variety of leaf colors and shapes. Some popular AGM-winning hostas include 'Francee', 'Gold Standard', and 'Earth Angel'.

Bergenia: These evergreen plants have large, leathery leaves and produce clusters of pink or white flowers in spring. Some popular AGM-winning bergenias include 'Bressingham Ruby' and 'Admiral'.

Ajuga reptans: This low-growing plant has creeping stems and blue flowers that bloom in spring. It is a good choice for groundcover in dry shade. Some popular AGM-winning Ajuga reptans cultivars include 'Catlin's Giant' and 'Purple Spark'.

Geranium cantabrigiense: This hardy geranium has blue flowers that bloom from late spring to summer. It is a good choice for groundcover in sunny or partially shaded areas. Some popular AGM-winning Geranium cantabrigiense cultivars include 'Biokovo', 'Karmina', and 'Rozanne'.

Nepeta x faassenii: This catmint has lavender flowers that bloom from summer to autumn. It is a good choice for groundcover in sunny areas. Some popular AGM-winning Nepeta x faassenii cultivars include 'Six Hills Giant' and 'Walker's Low'.