Birmingham Parks development officer Mike Hinton said: "Councils are losing their horticultural skills, identity and nurseries. We are fortunate we still have our nursery - it would make life difficult without it."
He added: "In the not-too-distant future, more councils will be buying from abroad, which will catch up with them in terms of bringing in pests and diseases and the expense of logistics."
Parish of St Helier parks department in Jersey won best in show for its Surfing Jersey display; Birmingham and Jersey also won golds at this year's RHS Chelsea Flower Show. Partington Parish Council also took gold.