There are ten 5th-level druid spells in AD&D, just as there were in OD&D. None of the spells are new; the only alteration from the OD&D spell list is that hold plant (which was dropped to 4th-level) has been replaced by insect plague. Otherwise, it's the rare case of a spell level that has survived relatively unchanged.
Animal Growth: Causes up to 8 animals within range to double in size, which also doubles their Hit Dice and damage. It should be noted that this doesn't necessarily mean that said animals will aid the caster, although spells like speak with animals and charm person or mammal are specifically called out as good ones to cast in conjunction with animal growth. Once again there are no guidelines as to what constitutes an "animal" in D&D, but it's been previously established that it means real-world animals, which also includes dinosaurs. So look out for those double-strength tyrannosauruses.
The spell can also be reversed, which halves animals in size, Hit Dice and damage. But it also lets those tyrannosauruses fit into smaller corridors...
The OD&D version of the spell only affected 1d6 creatures, and was also vague in its mechanical effects: it caused animals to "grow to giant-size with proportionate attack capabilities". Another one for the DM to figure out himself, I'm afraid. It didn't have a reversed version.
Animal Summoning II: Like animal summoning I, but it can summon six animals of up to 8 HD, or twelve animals of up to 4 HD. (Animal Summoning I could only summon eight 4 HD animals.)
In OD&D, this spell was a double-strength version of animal summoning I, which was quite different to the spell in AD&D: it allowed the summoning of one large animal, three of medium size, or six small animals. Whether the doubling of animal summoning II applied to Hit Dice or number of creatures (or both) is not made clear.
Anti-Plant Shell: Creates a barrier that keeps out all living plant creatures, such as shambling mounds or treants. Note that it specifies "living" plant matter; it won't stop clubs and arrow shafts or other wooden weapons. The OD&D version of the spell was much the same.
Commune With Nature: Grants the caster knowledge of the surrounding area, with a radius of half a mile per caster level. The caster can learn one fact per level, which generally means things like terrain, the presence of water, inhabitants, minerals, etc. It only works outdoors, so it can't be used to learn about a dungeon. (What if you cast it at the dungeon entrance, though? Would you then be able to learn things about a subterranean dungeon?)
The OD&D spell was effectively the same, but it specified that the Druid was communing with "higher powers". What those higher powers were was left unclear. Were they gods? Nature spirits? Who knows, but I'm happy to leave it unanswered; not every mystery needs to be solved.
Control Winds: This spell has a simple effect - it can increase or decrease wind force by 3mph per caster level - but the ramifications of that effect are anything but simple. The spell goes into how high wind speeds affect flying creatures, missile fire, structures, and sailing ships. The guidelines are bare bones, but evocative; I'd love to play a high-level druid that can uproot a city block with hurricane-force winds. The spell can be counteracted by the same spell cast by a higher-level druid. It can even be cast indoors or underground, but when this is done the "safe space" around the caster grows proportionately smaller, making the spell more dangerous for the druid's allies.
Insect Plague: Like the cleric spell of the same name, this spell summons a swarm of insects that obscure visibility, inflict 1 point of damage per round to all within range regardless of AC, and cause weaker creatures to flee if they fail a morale check.
The OD&D spell was similar, but didn't inflict any damage, and the creatures that it caused to check morale were a little weaker. It also lasted for a full day, as opposed to AD&D's more reasonable 1 turn per level.
Pass Plant: The caster of this spell can step inside a tree, and teleport into another tree of the same sort within range. Oddly, the range is dependent on the type of tree, and I can't really see the logic in it. Why does an oak tree grant a better range than an elm? Why do deciduous trees give a better range than coniferous? Only Gary knows, and I doubt anybody ever bothered to ask him. Anyway, the caster specifies which direction he wants to teleport, but he can only go that way if there's an appropriate tree there; if not, he is transported to the tree nearest to his desired location. If that tree happens to be in the opposite direction, well, that's bad luck. (This is another spell that's highly dependent on DM fiat; it's unlikely that the DM will have specified the type and location of every single tree in the forest, so it will all come down to the DM's decision, or a random die roll.)
The OD&D version of the spell is basically the same, only with some different range values for the various types of tree.
Sticks to Snakes: This spell is the same as the cleric spell, turning one stick per caster level into a snake (that may be poisonous). The druid version of the spell has a greater range, and requires mistletoe, but is otherwise unchanged.
Transmute Rock to Mud: Transforms a 2" cube per caster level of natural stone into mud. Creatures that can't free themselves from the mud (via flight, levitation or some other means) will sink down and suffocate, which is incredibly lethal if you play this by the book; it's an instant kill with no saving throw, and given its large area of effect could take out a small army in one go. The mud remains until a dispel magic or transmute mud to rock (the reverse of this spell) is cast on it, or until it dries up (a process requiring 1 to 6 days for every 1" cube).
The OD&D version of the spell had a fixed area of 30" square, and made no specific mention of creatures caught within being suffocated. It dried up in 3d6 days, regardless of area.
Wall of Fire: Creates a wall of amber fire that inflicts 4d4 damage (+1 per caster level) to anyone that passes through it, 2d4 to anything within 1", and 1d4 to anything within 2". Certain creatures susceptible to fire, as well as undead, always take double damage. The wall lasts for as long as the caster concentrates on it (or for 1 round per caster level without concentration). It can be shaped as a stationary wall, or a ring that moves with the caster, and only the side facing away from the caster inflicts damage.
In OD&D, the spell repelled all creatures of less than 4 Hit Dice, but it only dealt 1d6 damage to creatures passing through (although it still did double damage to undead). There was no mention of the ring version of the spell being able to move with the caster, and the spell only lasted as long as it was being concentrated upon. It's range was lower, and the area of effect was fixed rather than increasing with level as it does in AD&D.