Orange, I honestly believe that people just do no prior research on the plants that they're trying to grow. For example, Fynbos is native to South Africa. It should seem obvious that I could easily grow it in my garden. I don't even try. Why? Fynbos is native to the Cape province. The Cape is a winter rainfall area with sandy, acidic soils. Snow is known to happen and it gets cold. Heck, they even have their own ski resort. The summers are hot and dry. I live in KZN, which is classed as a sub tropical climate. I have dry winters, where my definition of cold is 10C. Summer is our rainfall season and is stupidly hot. Any fynbos I try to grow here would drown or die of heatstroke. Proteas and Suikerbos are ok though as they're a little less sensitive to the environment.
I've seen it time and time again with roses. The biggest mistake people make is not paying enough attention to the soil. Roses HATE standing in water, so any form of water logged/marshy soil is going to kill the rose. Considering that roses are however native to areas with regular rainfall, they do need to be watered regularly and soil that is too sandy is not going to retain enough water either. The pH of the soil is also really important.
Admittedly, certain roses have now been cross bred to be more suited to different climates, so it's worth looking for those. Here is a great beginner article though.
http://www.popularmechanics.com/home/lawn-garden/how-to/g1162/how-to-start-a-rose-garden/?slide=1I currently have a flowerbed that I absolutely nothing to maintain except go through maybe once a month to pull out the weeds. I can do this because the plants were specifically chosen to suit the area. Most are indigenous and those that aren't come from similar climates. I have one small bed that I molly coddle and have to look after every week because the plants aren't actually suited to the area. I do love arums though, they're worth the hassle :)