I am a plant known for my striking, often vibrant, flowers and I am a symbol of resilience, but I am also toxic. What am I?

1. I thrive in dry, sunny conditions and am often seen in rocky or mountainous areas.
2. My flowers can come in various colors, including pink, red, and white, and have a distinctive, five-petal shape.
3. All parts of me, including my sap, are poisonous and should not be ingested.
4. I am sometimes called the 'Desert Rose' due to my appearance and habitat.