Fleuroselect sunflowers (Helianthus) trial 2024
Objectives and purpose of the trial
Plants and location
What was planted?
Where is it planted?
The sunflower seeds were sown directly into the open ground in Floral Fantasia area at RHS Hyde Hall, Essex, and six entries, submitted as young plants, were planted directly into trials beds. Here are some considerations for planting out sunflowers:
- Sow seeds indoors in early spring to give them a head start
- Slugs and snails like to feast on young annual sunflowers, so it is worth waiting until your seedlings are strong, resilient and hardened off well to give them the best chance
- Position in full sun and in a sheltered spot
- Sunflowers like plenty of water, so consider applying a layer of mulch such as strulch to help retain moisture levels in the soil
Judges and criteria
Judges of the trial
Once the judges have concluded their overall assessment of the sunflowers, the results will be reviewed by the RHS Herbaceous Committee and announced in winter 2025.
The 2024 Fleuroselect sunflower forum includes: Mike Smith (Chair, Owner, WD Smith & Son Nurseries), David Creese (RHS Tender Ornamental Plant Committee member), Phil Johnson (RHS Herbaceous Plant Committee member and Director, Lion Seeds), Boyd Douglas-Davies (Managing Consultant, The Boyd Foundation), Alan Bourne (Owner, Perrywood’s Garden Centre), Adele Dyer (Principal Researcher and Writer, Which), Andy Bunker (Sales Director, Alton’s Garden Centre), Chris Finlay (Sales Director, Volmary), Michael Perry (Presenter and Influencer, Mr Plant Geek) and Molli Christman (RHS Horticulturist).
Judging criteria
The following factors are all taken into consideration as part of the judging of the trial:
- Flower performance
- Habit
- Colour and appeal
- Pest and disease resistance
- Longevity
Cultivation
Planting process
An organic nitrogen feed was added to the soil in spring before sowing and planting at a rate of 50g per metre squared. Once ready, the Floral Fantasia trial beds were marked out in April 2024 into 86 rows of sunflowers, one for each entry with five plants per entry. Each of the entries were arranged in height order according to the heights detailed by their suppliers. The rows were spaced 64cm apart and the five plants within each row were spaced 40cm apart.
A thin layer of strulch (a straw based mulch) was applied to the ground after the seedlings had established. The horticulturists working on the trial were careful to leave a space between the seedlings and the strulch to avoid burning the young plants. The strulch was applied to help retain moisture levels in the soil over the summer.
Additionally, soil analysis concluded that the soil in each trial bed was high in nutrients. Therefore, strulch was also selected for its ability to improve soil structure without overloading the soil with excess nutrients.
The sunflowers are watered regularly during the to prevent them from drying out.
How we’re managing plant health
How to grow sunflowers
Explore all the information you need to know to grow and care for sunflowers in your garden
Discoveries
Suppliers to the trial
Fleuroselect Members:
- Burpee Europe B.V.
- Evanthia
- Suttons
- Benary
- Thompson & Morgan
- Dobies
- EconSeeds
- H.M. Clause
- Johnsons
- Mr. Fothergill’s
Extended trials area:
List of plants in the trial
Handy tools and information
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Gardening advice
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Hardiness ratings
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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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