Martin,
It all depends what sort of photograph you are looking to take.
If you want a textbook type of photo then I agree with you, the plant is in the way and you cant see all of the butterflies markings etc.
However, from a different point of view it is a really nice photograph showing the butterflies habits etc. Nice angle, composition etc.
At first I seemed to go for the typical shot, butterfly with wings fully spread, ignoring the surroundings, flowers etc. But if I cant get that shot then I try to look for something a bit more creative like your shot
Like this one :
Oh and by the way, your first photo is fantastic
![Wink ;-)](./images/smilies/icon_wink.gif)