Half a million trees will be planted across England in the next three years to protect against extreme weather, the environment secretary, Angela Eagle, will pledge on Wednesday morning.

Mayors, local authorities, charities and grassroots groups will be given new funding and responsibilities for restoring natural landscapes such as wetlands, river edges and meadows, which can provide natural flood management and reduce the damage done by droughts.

The £79m package, to be set out in Eagle’s speech to the Labour party conference in Liverpool, will include £53m for tree-planting and £26m for “local nature recovery strategies”.