There isn't a single perfect adverb for "plant". The best choice depends on the context and what you want to express. Here are some possibilities:
Based on the action:
* Carefully: "She planted the seeds carefully."
* Quickly: "He planted the bulbs quickly before the rain."
* Deeply: "They planted the trees deeply to ensure their stability."
* Evenly: "The gardener planted the flowers evenly across the bed."
* Secretly: "He planted the evidence secretly in the garden."
Based on the result:
* Abundantly: "The farmer planted wheat abundantly this year."
* Generously: "She generously planted wildflowers along the road."
* Successfully: "They successfully planted the rare orchids in the greenhouse."
* Wildly: "The seeds were planted wildly, resulting in a beautiful array of flowers."
Other options:
* Vertically: "The farmer planted the corn vertically in rows."
* Horizontally: "The gardener planted the strawberries horizontally in rows."
Let me know the specific context, and I can help you choose the best adverb!