i think the easiest way to remove unwanted holly bushes is with a chain and a four wheel drive vehicle. in the absence of these elements, you will need a soaking rain, a shovel, a hand trowel, a hatchet, and lots of muscle and sweat.
first you chop the top off. this is rather fun, and if you're lucky your child may help you.
then you must dig and chop out the root ball. this part is not fun and your child will likely not help you. however, the sense of accomplishment at the end is totally worth the effort.
the dinky holly in the front yard take about an hour each from start to finish. the holly from hell in the backyard took three hours. at one point i truly thought its roots must be in the hands of the devil.
first i had to use hedge clippers and a hatchet to get all the branches off. this one did not have the one central trunk like the others. that was my first warning. then i set to work digging and chopping out the roots. it was a full two hours before the trunk shifted at all. i was beginning to doubt my abilities.
i persevered and was finally successful. oh what a feeling!
here you can see my trophies. the root ball to the right is one from the front yard. big difference. huge. i think i might paint that big one in rainbow colors and mount it on my shed. i'm so proud.
on a side note, you should really put on your yard shoes for holly killing. otherwise, you will murder your flipflop collection. meh. these were all on their third season anyway and after what i've accomplished, i guess i deserve some new kicks.