I want to bring Shamrock to the UK tomorrow can I?

I have 8 tufts of Shamrock with compost attached in little bags in my fridge. I hope to bring them to Wales with me tomorrow. I would put them in a zipper plastic bag in my suitcase if allowed but is this ok? Will I get pulled over by the customs officers? I know you can travel with it pinned to your collar as I've seen this before on St.Patricks day but I really want to bring it over to my Irish & Welsh friends in the morning. Can anyone advise me as to what to do? Do I need to wash the soil off and still carry it in my suitcase or can I leave it the way it is? Please help and Happy St. Patricks day to all!