When buildings are to be greened up, style questions arise sooner or later. Also: Which plants and growing systems are adequate? Or vice versa: "What does not work for me at all on my house or building"? The answers are very dependent on the date of origin of the buildings construction. Therefore the following pages treat the protection of historical monuments and different style epochs (eras) up to modern buildings. You can find suggestions and examples; at the same time we try to draw a history of building greening (source: Rudi Baumann, "Greened Architecture", Callway 1983). In the next chapter of "Ideas" it deals with different concepts of building greening.