I think really a lot of it is a matter of taste, but beyond that, I agree with safewrite. The story needs to be capable of supporting the lushness, and the lushness should enhance the story. And really: if you're going to use lush language, make sure you understand grammar and word meanings and so on; otherwise you just look ridiculous.

I like rich language sometimes, and I like simple language other times. I guess... I want to be able to understand what's being said, and I want what's being said to be worth thinking about. Like this, which mojodragonfly quoted, from Wild Comfort, by Kathleen Dean Moore:

Suddenly, streaks of light splatter toward our boat. They leap from the sea and patter against the swell, thousands of them flying clear of the water. They hit the boat like pebbles, clunking and bouncing off the hull, sparking back into the sea. I duck reflexively and brace my paddle for balance, but the lights strike the paddle blade too. The sea is alive with them, plunging toward our boat. They dive and flash. In the midst of the melee, a large blur of blue light surges toward our bow. Sparks glint to the heavens. Starlight plummets onto the sea, the fallen stars, the Lucifers. Their spread wings blaze one last time, then slide under the dark waves.

It's describing bioluminescent algae and single-celled organisms, and how strange and beautiful they look at night on the sea. In the following paragraphs, the narrator reflects on seeing just as much beauty and feeling just as much wonder in common things. The language here seems appropriate to me--it's to make us feel the wonder and strangeness and beauty--and THEN, the author's going to take the extra step and make us see that in the commonplace.