Mizuki nodded as Madison began to explain about her preferred method of fighting, patiently listening. Considering that druids were generally strong casters it wasn't surprising that Madison would prefer mobility and staying at a distance, although most druids prioritized supporitve magic over the more hostile style the rot druid clearly had been working on.
She didn't give a visible reaction regarding the mushrooms, aside from a single sweeping of her tail. She had some things to say about that, but she'd wait until after Madison had shared what information she was willing to share upfront. Given what she'd seen of the woman so far Mizuki doubted that she'd give everything immediately... Although she was certainly (and visibly) surprised when she learned about just how much effort Madison had put into researching the most dangerous and deadly of plants. Opening the received PM with a paw she scanned through the named plants and their uses, her eyes widening slightly before looking back at Madison.

Well, this certaily surpasses my expectations. I can't say I've got such detailed notes on anything I've figured out myself, but I'll try my best to give as much as I've received.
She then fell silent for a little bit, composing her thoughts and trying to think of information that would be useful to Madison.

Since you're a ranged caster I wouldn't expect you to need it often, but there's a group of wood called ironwood which you might find useful if you're in a pinch. Ironwood is often heavy enough to sink and combines toughness and hardness in a way which can make any woodworking tools go dull quite quickly.
She focused, and from the ground a piece of relatively dark wood began to grow, wrapping itself around the wolf's paw until it formed a single piece of armour, what on a human body would be called a bracer.

A good choice is what is called Lignum Vitae, or Pockholz. Before synthetic materials took over it was often used as material for ship parts which had to be very durable, sometimes even preferred over metal. It won't compete with the kind of enchanted armour that the heavy frontliners carry around but I doubt most other casters could pull up emergency armour of the same quality.
She dismissed the wood, putting it back in the ground as she looked up at Madison.

As you already know we can't control flesh and blood like we can control plants. However there's a way to still make use of your own body besides shapeshifting... You mentioned how those flesh eating mushrooms would take too long. If you cast it the normal way that is true, but there's another of casting nature magic, and it has to do with the reason why you can't use it without fertile soil or other plants nearby.
The following part was going to be rather tricky, so Mizuki changed back to her humanoid form. Still ignoring the fact that she was naked in the Emerald Garden she instead brought one sharp claw-like nail to the furred skin on her forearm.

You can either use your magic to create plants that only live as long as your magic feeds them, using present nutrients as a jumpstart, or create a more steady growth which allows the plants to remain but either requires so much energy that you can't create a lot of it or draw more of its growth from the nutrients present.
The third method is to force the plants to grow quickly without feeding them your magic as substitute, at which point they'll forcibly drain the source of the nutrients. More cost efficient for yourself but it'll leave fertile soil barren and plants withered depending on how big you grow it. That way you could have flesh-eating mushrooms devour their target quite quickly.
The other way to use this trick is to substitute yourself as food for what you're growing.
Using the sharp nail Mizuki created a small cut in her forearm, enough that some blood welled up. Focusing her magic the blood began to reshape itself, stretching out until a sanguine thorned vine was rising up from the wound, roots wrapping both around the caenis's arm and digging into her skin.

I strongly advise not using this in combat without a lot of practice, because if you don't control it well you'd pretty much be killing yourself.