When in doubt, head to Hogsmeade
Hogwarts Legacy has a lot of crafting opportunities for those that dig those systems, including the chance to gather, buy, and create ingredients/reagents. Here’s where to find Fluxweed stems and seeds, and how to grow them.
You can buy Fluxweed stems and Fluxweed seeds at The Magic Neep in western Hogsmeade
If you want to just buy Fluxweed stems outright, you can find them at The Magic Neep, on the western side of town (it looks like a farm house on the outskirts of the main city streets).
Fluxweed stems are 150 gold each, while seeds will run you 300 gold. Yes, you can choose to grow Fluxweed with seeds instead of buying them!
You can buy large pots at the Tomes and Scrolls shop – What do they do?
Players are free to hunt for ingredients or buy them from shops, but there’s another option: planting.
More specifically, you can buy a scroll to unlock the ability to create a potting table with a large pot at the Tomes and Scrolls shop in Hogsmeade. Some plants require a larger pot, and the smaller base ones will not be sufficient.
For a hefty price of 1000 coins, you’ll be able to grow plants with the potting table in the Room of Requirement, including Fluxweed.
What does Fluxweed do? You can use it to craft Focus Potions
Fluxweed is the core ingredient for Focus Potions. Focus Potions can be really useful in some of the tougher battles in Hogwarts Legacy, as it reduces the cooldown on spells when it’s active.
If you have active challenge quests that ask players to “have multiple enemies floating off the ground at once,” or suffer the effect of multiple spells at once, this is a really easy way to cut those cooldowns and sling spells to meet those requirements.