Just kidding, it probably won't work. A French consultancy called the Ginger Group has proposed a scheme that would cover the Eiffel Tower in greenery, ostensibly motivated by increasing levels of air pollution in Paris. Not to play the Grinch here, but the inherent wind loads on the structure -- combined with the amount of soil needed to nurture such plants (EDIT: one commenter tell us this isn't an issue!) -- might make their plan a tough one to sustain.
The group says they want to convey the city's newfound commitment to sustainability (stuffy old monument to mechanical ingenuity cramping your new "sustainable" image? Cover it in trees!). The weight of the plants would total around 400 tons. They'd install an irrigation system, and even blanket the greenery in lights so that the Tower could still "sparkle." Unfortunately, the task of keeping these plants alive can be quite cost and time intensive, depending on the systems used. Indeed, the Ginger Group says the installation alone would cost about $100 million dollars. As many commenters are pointing out, high winds would probably contribute to soil erosion, leading to an Eiffel Tower covered in dead, brown ferns. Then again, green wall technology improves every year. Infographic, .
EDIT: A commenter writes in to say, "you clearly don't understand hydroponics or vertical gardens. Using a drip system originating at the top of the structure, it is possible to have a solution of nutrients delivered directly to the plants' root system in some sort of media such as rockwool or clay pellets, with the solution being collected at the base of the structure and taken back to the top, completing the cycle. This would eliminate the need for soil and dramatically cut down on the amount of space needed for the roots. The only difficulty would be planting and performing maintenance (pruning, replacing dead plants), but soil would not be a problem."
Above all things, we're definitely not experts on hydroponics or vertical gardens. Sounds like soil is not an issue in the scheme. Thanks for the comment!
The Eiffel Tower in 1888.