No doubt advertising affects language. Where would we be without the free gift, new and improved, or supersize? (Perhaps writing more grammatically and eating more healthily...) In yet another attempt to reduce English to features and selling points, advertisers often use luxuriant to describe their products or services:

Luxuriant Cracked Heel Repair

Luxuriant Christmas Tree Wallpaper

Miralux Luxuriant Mattress

Problem is luxuriant means lush growth; thick and rich. As in a luxuriant growth of leaves in the spring. What those advertisers really want is luxurious, as in self-indulgent; comfort, elegance, or enjoyment in the extreme:

Mediterranea ... is a luxurious community situated adjacent to the sea, boasting stunning views of the Mediterranean.

This luxurious penthouse at the One Hyde Park development in the Knightsbridge of London just sold for a record-breaking £140 million or $220 million.

French President Nicolas Sarkozy orders brand new, luxurious presidential jet to rival Air Force One

As a society, we tolerate a lot of bent or outright broken language rules in advertising. We tune a lot of it out, anyway. But the careful writer should not emulate advertising-speak and should be wary of copying its word usage. Using luxuriant for luxurious is very much considered an error and is to be avoided.