You certainly can add spice to Mead.
Powder or ground spice is really not a good idea as it is almost impossible to remove without filtering, will continue to impart flavor and likely will over power the Mead.
I have added whole spice to Mead a number of ways, have settled on adding them to secondary. I found that in primary the flavor tends to get blown out the airlock. It does work but generally makes for a nice smelling brew area and just too hard to control.
My preferred method is to just drop them in the mead and rack off them after a week or two I have also soaked them in a very small amount of vodka for a day, place them in a sanitized bag and just drop them in. (Makes it really easy to retrieve and less likely to add any bacteria or foreign matter but in secondary not too much of a concern.)