The groups behind the city’s largest parks are lending their much smaller city cousins a lot of green thumbs.

The parks department said eight conservancies, such as the Central Park Conservancy, Friends of the High Line and the Prospect Park Alliance, have met or exceeded their combined $15 million commitments to the city’s Community Parks Initiative, which launched in 2014 to provide funding and resources to improve smaller parks in the city.

Kate Spellman, a senior adviser for the parks department, said in addition to providing extra funding, the nonprofits have provided landscape experts and training that will benefit all the open-space locations in the five boroughs.

“They’re not just going in and completing an improvement and disappearing. They’re improving with our staff so they are teaching,” she said.

State Sen. Daniel Squadron, who proposed the initiative, predicted that this partnership will grow.

“Our system of parks is strengthened by its conservancies,” he said in a statement.

Some of the improvements made by the conservancies since 2015:

-The Central Park Conservancy completed 25 turf renovation projects at 15 different park sites, and trained 150 parks employees on turf maintenance.

-The Friends of the High Line supported a dozen community gardens in the South Bronx with infrastructure improvements and maintenance materials.

-The Prospect Park Alliance has completed a new design for the Stroud Playground in Prospect Heights and working on a new look for Epiphany Playground in Williamsburg.

-A board member of the Madison Square Park Conservancy member donated $100,000 to a nonprofit that will maintain and improve Herbert Von King Park in Bed-Stuy.