Of The Home Circle:

Magickal plants growing outside the home in containers can be placed around the 
circle or on the altar during ritual. If you primarily work indoors, choose an 
odd-numbered selection of sacred plants and grow these in your ritual area. If 
they need more sunlight, simply move them outdoors and bring inside during 
ritual. Give them energy and love, and they'll aid you in your worship and 
magick.

Though any but poisonous plants can be used, such plants as these are 
recommended:

 African Violets    Red Geraniums
 Cacti (all types   Rose
 Ferns (all types)  Rose Geranium
 Holly              Rosemary
 Hyssop             Ti (Cordyline terminalis)
 Palms (all types)  Wax Plant (Hoya carnosa)