I'm sorry to hear about your loss farmpony. Anyone who has any kind of pets know they are just like family. **hugs** I like the lilac bush myself (good suggestion) not only are they preety they smell good too!!
I think the lilacs would be a good choice. Maybe a rose bush...I did a quick google search on perennial flowers and I found dahlia flowers. There are a lot of different kinds it looks like...if you type it in google and go to images you will see all kinds of them. They are very pretty. I don't know anything about flowers though so I'm not sure how feasible these would be!? I don't know anything about them other than they are pretty :)
I'm going to go to home depot this weekend to get something... I'm leaning towards a pink rose bush (since she had breast cancer). My trainer has her daughter and I saw her last night... It made me happy and sad at the same time.... :(