Yeva, Nature's Herald
Legendary Creature — Elf Shaman
Flash (You may cast this spell any time you could cast an instant.)
You may cast green creature spells as though they had flash.
"I can call an army to my side in the blink of an eye. Best not blink."
Eric Deschamps
Rulings
You still pay the costs for green creature spells you cast.
(wotc • 2012-07-01)
Yeva's ability applies to green creature cards in any zone, provided something is allowing you to cast them. For example, if the top card of your library is a green creature card and you control Garruk's Horde, you can cast that card as though it had flash.
(wotc • 2012-07-01)
Rulings
You still pay the costs for green creature spells you cast.
(wotc • 2012-07-01)
Yeva's ability applies to green creature cards in any zone, provided something is allowing you to cast them. For example, if the top card of your library is a green creature card and you control Garruk's Horde, you can cast that card as though it had flash.
(wotc • 2012-07-01)