The magick circle may be  fashioned with garlands of flowers sacred to the Goddess  and God. Alternately, flowers can  be scattered around the perimeter of the circle.

The  point stones may be ringed with fresh flowers and herbs suitable to the elements, such as:
North:  corn, cypress, fern, honeysuckle, wheat, vervain
East:  acacia,bergamot,clover, dandelion,lavender,lemongrass, mint, mistletoe, parsley, pine
South: basil, carnation, cedar,chrysanthemum, dill, ginger, heliotrope, holly, juniper, marigold, peppermint
West:  apple blossoms,lemon balm,camellia, catnip,daffodil, elder, gardenia, grape, heather, hibiscus, jasmine, orchid

Fresh flowers  may be present on  the altar or,  if none are available, greens such as ferns may be used.

When casting the circle around a tree, you can use the fruit, leaves, nuts or flowers of that tree to mark out the circle, if desired.
All of these can be used in addition to the cord and stones.
 
Creating a Living Indoor 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)
 
~from Maat's Book of Shadows