FYI, boiling any aerial plant parts is a surefire way of extracting any bitter compounds in the plant, which is the reason that hops are boiled in beer. Hot steeping cuts down on bitterness because not as many bitter compounds are released. Cold steeping virtually eliminates bitterness, but extends the time needed to extract flavors a lot.
Squeezing boiled or hot steeped plant matter also extracts more bitter components
This applies to any leaves, stems, or flowers.
Because they tend to be woodier, roots almost always have to be boiled to extract anything from them.
An alternative is to make a tincture using a little neutral grain spirits such as a good quality tasteless vodka. Pour the vodka over the fresh bruised or dried plant material, cap, and leave in a cool dark place. Shake it every day. After a week, strain off the tincture and check the strength. If it is strong enough, cap it until ready to use. If not, pour it over more (unused) herb and return to storage, shaking every day. Repeat until the tincture is as strong as you like it.
A tincture should probably be added to secondary, and should be used very carefully, as the flavors can get very concentrated.
Edit:
Since alcohol is so good at getting flavors out of plant matter, you might try just putting the stuff in a hopping bag and dunking it in the secondary. The biggest problem I can see with this is that the risk of contamination is higher...