From Hades

[Brownlie]

Generally, when I see myths I look for them being used in a new way. 

Six months, too short, have slipped away -- quickly after have may work better than too short.
And now she must leave me... --The meter sounds off here.
Now flowers in the world above
Bloom for Persephone.

The mortals in that upper realm -- "that" is padding to fit the meter.
Rejoice and sing their songs,-- "and" plus "their" seem to be expendable.
But little do they know that here
Is where my dear belongs.

Though "here" is somewhat cold and dark -- This may be your most compelling line, perhaps.
It's where she wants to be 
Just six more months until my bride
At last returns to me.

As a metrical exercise I don't think this is so bad. However, the content doesn't seem to say anything to innovative. I pad meter all the time. So, I wouldn't say I'm better than you. Thanks for posting.