It can be hit-and-miss. With a bit of trial and error you start to see which prompts work well to generate pleasing images. Some people have done excellent work exploring ways to change the look, like https://imgur.com/a/SnSIQRu

As for hardware, a lot of my experimenting is done on Google colab. For this plant generation stuff I rented a GPU via vast.ai for ~$0.20 an hour and set it running overnight.