Where is flower paradise and hall of origin in pokemon diamond?

Question:

Answers:
The flower paradise is a route extension, like the turnback cave added after beating the E4. but you need the event destributed item, OAK'S LETTER., or AZURE FLUTE for arceus, take it to the spear pillar and play it to start a staircase to the heavents, grab yourself that god pokemon. neithger event has happened yet though.