Tulipa (tulip), double late, parrot and coronet trial results 2025
Objectives and purpose of the trial
Tulips in full bloom display a spectrum of colour in May 2025
A vibrant sea of tulips in full bloom fills the trial beds at RHS Wisley
What is an RHS Award of Garden Merit?
The RHS Award of Garden Merit (AGM) is intended to help gardeners choose plants that are likely to perform well, and is only awarded to plants that are:
- Excellent for ordinary use in appropriate conditions
- Available
- Good constitution
- Essentially stable in form and colour
- Reasonably resistant to pests and diseases
Judging criteria
The following factors were all taken into consideration as part of the judging of the trial:
- Overall appearance – proportions, sturdiness and foliage
- Flower impact – colour, size and shape
- Length of flowering period
- Weather and pest resistance
- Uniformity of height and colour
Tulipa AGM winners
Tulipa 'Dee Jay Parrot' (10)
tulip 'Dee Jay Parrot'
- 0.1–0.5 metres
- 0.1–0.5 metres
Tulipa 'Caribbean Parrot' (10)
tulip 'Caribbean Parrot'
- 0.1–0.5 metres
- 0.1–0.5 metres
Tulipa 'Dee Jay Parrot' (10)
tulip 'Dee Jay Parrot'
- 0.1–0.5 metres
- 0.1–0.5 metres
Tulipa 'Caribbean Parrot' (10)
tulip 'Caribbean Parrot'
- 0.1–0.5 metres
- 0.1–0.5 metres
The trial ran across all weathers from warm sunshine to wind and heavy rain. There were notable variations in the length of time the different cultivars were in flower, with some tulips flowering for just a few days and others for a number of weeks.
Why the AGM was awarded
Forum assess the Tulipa trial in April 2025 at RHS Wisley
The tulip forum assessing the trial at RHS Wisley in May 2025
AGMs rescinded
Plants and location
What was planted?
This trial showcased 80 distinct selections of tulips, featuring a dazzling array of double late, parrot, and coronet forms. Specifically, the trial included 43 double late tulips (some of which were also fringed), 30 parrot tulips, and seven coronet tulips. The bulbs were sourced from leading UK suppliers, who in turn worked with expert growers and exporters in the Netherlands – the heartland of tulip cultivation.
Each type of tulip brought its own personality to the trial display:
- Double late tulips are lush and layered, with a fullness that often mimics peonies – hence their nickname, peony tulips. They bloom later in spring, adding a final flourish to the season
- Parrot tulips are flamboyant, with petals that twist and curl into feather-like shapes. Their laciniate edges, sometimes streaked with bold, contrasting colours, give them an almost exotic flair. These striking flowers have been celebrated since the early 17th century.
- Coronet tulips are the newcomers of the tulip world. With petals that curl inward to form a crown-like shape, they stand out for their sculptural elegance and impressively long flowering period
Where it was planted?
The tulip bulbs were planted in the open ground across two trial beds in the Trials Garden at RHS Wisley, creating the foundation for a vibrant spring showcase. Here are some considerations for planting out tulips:
- The best time to plant tulips is in November
- Pick a sunny, free-draining site in the garden
- Alternatively, plant them in containers in peat-free compost that drains well
- Remember to water them during the growing season
- Double late, parrot and coronet tulips all flower in late spring, which is why they are best planted together
Cultivation
Planting process
In November 2024, the tulip bulbs were carefully inspected in the Propagation area for any signs of rot or disease before being planted. Once cleared, the Garden Team set to work, placing each bulb into shallow trenches – 10 cm deep, 50 cm wide, and 100 cm long – with a layer of horticultural grit at the base to ensure excellent drainage.
The bulbs were arranged with precision: grouped alphabetically within their categories of double late, parrot, and coronet tulips. Each cultivar formed 10 neat rows of five bulbs, with two blocks of 50 arranged across the width of each bed. Spaced 60 cm apart, a total of 80 entries were planted across two trial beds.
Once the planting was complete, the beds were dressed with a layer of strulch to suppress weeds, and a low solar-powered electric fence was installed around the perimeter to keep inquisitive badgers at bay.
How plant health was managed
Challenges
The trial benefited from a relatively trouble-free year. Early on, Tulipa ‘Parrot Prince’ showed initial signs of Botrytis tulipae – commonly known as tulip fire – but was swiftly removed from the trial, preventing any further issues. Throughout the trial year, the RHS Trials team remained vigilant for this destructive fungal disease, which leaves telltale brown spots, twisted and withered foliage, and in severe cases, gives plants a scorched, fire-ravaged appearance. Thankfully, no further traces were found, allowing the rest of the tulips to flourish.
Weather
During the growing season, RHS Wisley faced an unexpected challenge with colder-than-usual overnight soil temperatures in February and March 2025. This chilly start slowed the tulip trial, with many plants emerging noticeably shorter than anticipated.
Early April 2025 brought a dramatic turn of events with two intense downpours that be-headed some tulip entries, including Tulipa ‘Sun Lover’. Yet, this moment of adversity truly highlighted the remarkable resilience of the remaining varieties, which stood strong despite the harsh conditions.
The trial concluded when a spell of hot, dry weather in late April 2025 caused later-flowering varieties to bloom and fade in rapid succession, cutting short their flowering display.
How to grow tulips
Explore all the information you need to know to grow and care for tulips in your garden
Discoveries
May 2025 | Growing habits
The trial forum noted some unusual growth patterns in the coronet cultivars, where the stems appeared to snake up and down. The RHS Plant Health investigated this and confirmed that no viral or bacterial factors were involved, attributing the phenomenon instead to environmental conditions.
April 2025 | Beheading
The two intense rainstorms in April tested the resilience of the tulip entries on trial – some, like Tulipa ‘Sun Lover’ (pictured), lost their heads to the downpour, but the remaining entries stood tall, proving just how weather-resistant tulips truly are.
November 2024 | Frosty weather
The first few days of planting out the tulips at RHS Wisley involved braving some frosty late-November weather.
November 2024 | Tulips in pots
A member of the RHS Wisley Garden team added an extra layer of colour and creativity to the trial beds by planting terracotta pots with tulip bulbs.
November 2024 | Does it matter which way up you plant tulip bulbs?
Gardeners have long been told to plant tulip bulbs with the pointed end facing upwards – but does it really matter? Barbara Beyrath from the RHS Trials Curatorial investigated and found that the answer is no; tulip bulbs will flower regardless of which way they’re planted. However, orientation does affect timing: bulbs planted ‘pointy side up’ tend to flower first, while those planted ‘pointy side down’ may bloom two to three weeks later.
Who was involved?
Judges of the trial
The 2025 Tulipa judges included: Teresa Clements (Chair, RHS Bulb Expert Group), John Amand (Director, Jacques Amand International), Camilla Bassett-Smith (Television Presenter and writer), Fergus Garrett (Great Dixter Head Gardener, Horticultural Educationalist), Adam Taylor (Director, Taylors Bulbs), Richard Wilford (Royal Botanic Gardens, Kew), Pollyanna Wilkinson (Garden Designer), Clare Brown (Owner, Plant Passion), Lucy Bellamy (Journalist and author) and Jenny Bowden (RHS Garden Advisor).
Photography: Plant and judges portraits provided by Nicola Stocken.
Suppliers to the trial
List of plants in the trial
Handy tools and information
- Full article - Filter for AGM plants and refine by colour, height and season of interest
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Get in touch
For more information on our RHS Plant Trials or to access older trial reports, please get in touch with our team via email at [email protected].
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