transitive + intransitive
: to fertilize (something, such as a crop) more than is necessary or appropriate
… can grow in various habitats, including soil that has been overfertilized.—Discover Don't try to force it to grow where it's not suited, don't overwater, don't overfertilize and don't get so obsessed with having a weedless yard.—Jim Auchmutey Some manures … can be tilled directly into the soil without worry of overfertilizing.—Brian Barth
… overfertilization can cause the plant to be in an undesirable state at time of harvest.
Though peonies are hearty feeders, avoid overfertilization, especially with nitrogen.