Is it considered "rude" to keep some of someones ashes and spread the rest?

My mommy just recently ped away and she was cremated. we wanted to get these necklace's that are shaped like hearts and you can put some of her ashes in it. is it okay to keep some of her ashes for the necklace and spread the rest? we are going to Hawaii to spread her ashes as she wished , and then we where going to plant a tree in our back yard and put some of her ashes there to. Is it like bad or rude to have her everywhere or just keep her in one spot? thanks!