Cantrips (at will): druidcraft, mending, poison spray, thorn whip

1st level (4 slots): absorb elements, cure wounds, entangle, faerie fire

2nd level (3 slots): animal messenger, beast sense, earthbind, hold person, wither and bloom

3rd level (3 slots): call lightning, freedom of the waves, meld into stone, wall of water

4th level (3 slots): blight, dominate beast, guardian of nature, ice storm, stoneskin, wall of fire

5th level (3 slots): contagion, geas, insect plague, mass cure wounds, maelstrom, tree stride, wrath of nature

6th level (1 slot): heal, investiture of ice, primordial ward, sunbeam

7th level (1 slot): fire storm, reverse gravity

8th level (1 slot): tsunami

9th level (1 slot): foresight, storm of vengeance

Staff of the Woodlands. The archdruid has a staff of the woodlands. The staff has 10 charges for the following spells, which take an action to cast: 

animal friendship (1 charge)

awaken (5 charges)

barkskin (2 charges)

locate animals or plants (2 charges)

speak with animals (1 charge)

speak with plants (3 charges)

wall of thorns (6 charges)

pass without trace (0 charges)

Tree Form. The archdruid can use an action to plant one end of the staff in fertile earth and expend 1 charge to transform the staff into a healthy tree. The tree is 60 feet tall and has a 5-foot-diameter trunk, and its branches at the top spread out in a 20-foot radius, complete with a fully-formed treehouse. 

Scimitar. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) slashing damage.

Staff. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 4) bludgeoning damage.

Change Shape. The archdruid magically polymorphs into a beast or elemental with a challenge rating of 6 or less, and can remain in this form for up to 10 hours. The archdruid can choose whether its equipment falls to the ground, melds with its new form, or is worn by the new form. The archdruid reverts to its true form if it dies or falls unconscious. The archdruid can revert to its true form using a bonus action on its turn.

While in a new form, the archdruid retains its game statistics and ability to speak, but its AC, movement modes, Strength, and Dexterity are replaced by those of the new form, and it gains any special senses, proficiencies, traits, actions, and reactions (except class features, legendary actions, and lair actions) that the new form has but that it lacks. It can cast its spells with verbal or somatic components in its new form.

The new form’s attacks count as magical for the purpose of overcoming resistances and immunity to nonmagical attacks.