Bring a pot of salted water to a boil (roughly 1 tablespoon per quart of water)
Add the silphium shoots and cook for 1-2 minutes.
Remove the shoots and cool naturally, do not shock them in ice waer as it may cause them to discolor-they need the residual heat of cooling to retain their brilliant green.
Taste a shoot. If you find it a bit strong for you, soak the blanched shoots in water in a bowl in the fridge (leaving them on the counter will shorten their shelf life) for 2-3 hours, then drain, pat dry, and refrigerate until you're ready to use them, preferably in a day or two.
Add the shoots, whole, without chopping them, to dishes where a small vegetable like bok choi would be welcome. They're particularly good with rice bowls, and in small amounts as a garnish. They can also be served, dressed with olive oil, salt and a dash of fresh lemon juice if you like the flavor of them straight up, or served as a vegetable side with some sort of aggressive condiment.
Notes
It's very important that the greens are not shocked in ice water after blanching, which can cause them to discolor.