Deusovi has decoded the riddle, to which the answer is:
DANGER
First line
When down vith wrath the risk abounds
This is a cryptic clue: D for down and ANGER, wrath. To take a risk means to expose oneself to danger.
Second line
The sawbones endless saint surrounds.
And another cryptic clue: DR for doctor or "sawbones" surrounds ANGE[l], an endless saint: D(ANGE)R.
Third line
A curser who is somewhat meek,
Someone who says "Dang!" could be a danger.
Fourth line
A tunesmith who perhaps goes squeak,
This refers to Danger Mouse, a musician and a cartoon series.
Last line
A tangled garden this you seek.
Danger is an anagram of GARDEN, as Deusovi found out.
Title
The title is probably related to danger or the code somehow, but I haven't found out how.