Adorable! There is a mini gardening forum here. You can also search the database for plants indicated as suitable for mini gardens:
http://garden.org/plants/searc...[2]=&select[4]=&select[186]=&text[5]=&text[6]=&box_other[652]=&box_other[789]=&box_other[1651]=&box_other[790]=&box_other[41]=&box_other[42]=&box_other[43]=&box_other[728]=&text[291]=&text[290]=&box[9][1652]=on&box_other[1635]=&box_other[77]=&box_other[81]=&box_other[82]=&box_other[83]=&box_other[84]=&box_other[85]=&box_other[90]=&box_other[648]=&box_other[1591]=&box_other[111]=&box_other[996]=&box_other[108]=&box_other[1572]=&box_other[1669]=&box_other[1511]=&select[317]=&text[314]=&text[315]=&submit=Search!
Pasting a link to completed search doesn't seem to be working. Click plant database, then search by characteristics, click the box for "suitable for mini gardens," click search.