So has anyone tried using Roselia on a serious team? I was looking for Spikers for a team that was testing out some random sets, and I wasn't all that impressed with Qwilfish. For a laugh, I decided to try out Roselia, and I have to say, I was really quite impressed. With a fully specially defensive EV spread, Roselia has very little trouble setting up on the two most common Pokemon in the tier, as well as basically any bulky water, Clefable, Weezing, Chansey, some Rotom, etc. In addition to Spikes, Energy Ball, and Rest, Roselia can use Leech Seed, Stun Spore, Toxic Spikes, or Sludge Bomb (it has the same 100 SpA stat as Venusaur can you believe). 50/45/80 defenses are poor but definitely salvageable (Qwilfish only has 65/75/55), and the 65 base Speed isn't bad for outspeeding a lot of the Pokemon that hang around the 50-65 base speed area. On average, Roselia takes 39% from defensive Milotic's Ice Beam (which after Leftovers might not even 3HKO), and as we know the best defensive Milotic set doesn't even run it. It takes 46% from Venusaur's Sludge Bomb, which is a lot but it's still low enough for Roselia to be of use against it, especially after coming in on a Leaf Storm (18% damage).
Overall it's quite a weak Pokemon and arguably outclassed by Qwilfish, but it's got that ever so handy 4x Grass resistance, better special bulk, and Natural Cure-Rest. It's pretty anti-metagame atm and very effective at it too, and overall really good fun to use!