Is it ok for a cat to eat a frilly fern? I have no access to gr for the cat to get its usual greens.?

My indoor cat likes eating gr and rose leaves, so I usually kept a container of cat gr for him to snack on when the need arose. Now I have no access to those products but experimented with Garfield's favorite - a fern. Before he seldom up-chucked but he seems to upchuck everytime after a nibble on the fern - what other plants can I use that will seem tasty to the cat but not induce such a dramatic effect. I have tried all kinds of herbs including fennel and garlic flowers but they do not appeal to my pampered feline.