I would choose a nettle, as Admiral Butterflies do. There flowers aren't extravagant but the poison tipped spines are very good protection.
Which nettle you may ask (as there are many)
Ideally Urtica sykesii for its beautiful triangular leaves perfectly embellished with triangular edges which itself have beautiful spikes (one of my favorite plants).
For added protection the most dangerous nettle Urtica ferox a nettle so big it has become a woody tree with thick spikes as long as your nose, loaded with enough poison to kill a dog or leave a man limp for weeks (I would make sure no dogs are harmed). The beautiful red admirals favorite choice.
Brutal for everyone underneath, but the flowers of Dionaea muscipula are on long stalks keeping you safely above the gaping jaws below.
Just make sure not to have any fermented plum juice before you go, as you may be to tipsy to stick the landing:
Red Admiral butterflies getting drunk on plums