Had an interesting experience last week that I needed to bring to someone's attention. I was running a quest and told my group, "Hold on I'm getting some really nasty artifacting here." Turns out, it wasn't my computer/graphics. The Ranger in my party was casting the spell Spike Growth.
For the most part, DDO is visually stunning; character detail, armor/weapons, landscape, spells, all outstanding. Sure, the Shining Adamantine Plate looks like dingy longjohns and a brown sports bra, but even that I can deal with. Spike Growth is downright terrible. It's pixelated, has little discernable form, greyish, and it's low quality is unlike any other element of the game. See example (and yes, that's on High graphics).
Take as a counter example, the purple crystal growth all over the Gianthold (not the giant ones, but the ground cover). Small clearly defined clusters that look like clumps of grass. They look more natural and would be a great source material for Spike Growth to be updated in the future (colored green or brown as natural spikes of course).