Northumberlandia, created by landscape artist Charles Jencks and described as the world's biggest human landform, is being finished with a bespoke seed mix.
The landscape, in the shape of a reclining woman, needed a more technical method of seeding because of its curvaceous form on the Blagdon Estate near Cramlington (HW, 16 March).
"People unconsciously empathise with forms that relate to their physiognomy, particularly the face and torso," said Jencks. "The far-off Cheviot Hills are pulled into the foreground by the similar curves of the body."
DLF Trifolium Johnsons and seeding company CDTS teamed up to create and apply the bespoke mix, which will put the finishing touches to a project first mooted a decade ago and funded by the estate and Banks Group.
Northumberlandia will form the centrepiece of a 19ha public park and is 34m high and 400m long. Around 1.5 million tonnes of soil and clay from a nearby surface mine were moved to create the undulating landscape.
"Hydroseeding was the only method that would deliver results," said CDTS North West manager James Thomson. "The contours required a seed mix with low maintenance, quick coverage and nitrogen building that would green up quickly."
The team sprayed a mix of microclover and grass, mulch, fertilisers and binders. Northumberlandia is due to open later this year.
"Our brief was to prepare a mix that was low-maintenance, drought-resistant, robust and able to cope with a low-nutrient environment. Microclover was the key because it helps to fix nutrients from the atmosphere. In the sloped environment, the soil is likely to leech nutrients, so cultivars that maintain levels were crucial for it to stay green."
- Paul Hadley, amenity sales manager, DLF Trifolium Johnsons