in any forest
you could find oddish in the Ilex Forest at night.
you can only find it at night in the little forest { down south } in the johto region in soul silver.
They appear at Night time.
In Ilex Forest, morning and night only.
Route 5, Route 6, Route 24, Route 25, Ilex Forest, and Safari Zone (Marshland).
Oddish evolves into gloom at level 21. It will evolve into bellossom by use of the sun stone. Into vileplum by leaf stone. :)
Level it up to level 21, and it will evolve into Gloom.
In order of how he wants to see them (based on Heart Gold and Soul Silver): Gold/Heart Gold: Oddish - Leaf Stone Growlithe - Fire Stone Pichu - Thunderstone Jigglypuff - Everstone Marill - Water Stone Silver/Soul Silver: Lickitung - Everstone Oddish - Leaf Stone Staryu - Water Stone Vulpix - Fire Stone Pichu - Thunderstone
you can catch one on route 24 in the tall grass
In the house above Cerulean, near the 5 or 6 trainers you have to beat. He wants to see an Oddish btw.
you can not get regirock in soul silver but in platinum you can in a special event.
there isn't