"It's really exciting, it's such a traditional event with so much prestige. I think it's great that they are happy not to take themselves too seriously and have a bit of fun with it," she said.
"Gnomes and garden figurines have always been a lot of fun for kids and they have that folklore magic ... they are quite fun whimsical creatures and that's where the connection with us comes through, it's a very antipodean connection to such a big event."
A Horticulture Society spokesman said the New Zealand products had generated a lot of support for its Campaign for School Gardening appeal to create 15 horticultural apprenticeships in the next three years.
"Overall the campaign has been incredibly well received, already the gnomes are collectively fetching over £3000 ($5500)."
Ms Hayman, an Auckland-based mother of two, started Seedling in her laundry in 2007, and now exports its 350-product range throughout Europe, the US, Asia and Australia.
It is not the first time celebrities have been associated with the products, with Jessica Alba and Heidi Klum among fans.