Hi Glenio. what a sad quest for you to perform, what about taking a packet of wild flower seeds to sprinkle on the mountain side, I'm not sure about the pro's and con's of taking plants into another country, you will need to check that out.

Hi Glenio and welcome to GoY, whilst I can appreciate your wish to commemorate your friend please only consider planting a native species and then get advice as to whether it is appropriate... Sadly a lot of the Scottish mountains are littered with various shrines, memorials and the like to dead friends. A growing plant is obviously a better choice so long as it fits into the landscape. So if we know where the mountain is we can, hopefully, give you some help.