Choosing plants to accompany geraniums (Pelargonium hortorum) in a pot combines home decorating skills with gardening. Because the plants share a container, they must have similar water and light needs. Choosing plants of different heights causes each plant stand out and keeps the container from looking crowded. Plants with different-shaped leaves and textures add visual interest, much in the same way as using textured cushions on a couch.
Plants chosen for their foliage serve as interesting backgrounds for the showy geranium blooms. Coleus (Solenostemon coleus) is a good choice because there are so many varieties. Leaves can be pale or dark green and plain or variegated. Coleus also comes in an array of colors from pale pink to red to bright purple. You can choose a coleus to match the colors of the geranium flowers or to contrast to make the flowers stand out. The pointed coleus leaves also provide contrast to the round leaves of the geranium. Other colorful foliage plants that grow well with geraniums are polka-dot plant (Hypoestes phyllostachya) and shamrock (Oxalis).
You can offset the large, round geranium leaves with ferns. Maidenhair fern (Adiantum raddianum) has long fronds lined with small leaves that drape and frame the geraniums. Silver brake fern (Pteris cretica) has long, narrow variegated leaves ending with frilled tips. Asparagus fern (Asparagus plumosis), also called florist’s fern, has long stems with light feathery leaves that grow around and through other plants so that the fluffy foliage pokes through randomly.
Geranium flowers aren't valued for their fragrance so adding some scent to the plant grouping provides another layer of sensory appeal. One way to do this is to choose geranium varieties with scented leaves. Possible geranium scents include rose, lime, ginger, lemon or even chocolate. Lemon verbena (Aloysia triphylla) has tiny lavender flowers but it stands out for its aromatic lemony leaves. Lemon verbena can be taller than geraniums so there should be some space between the two in the container. Fragrant herbs such as basil (Ocimum basilicum) or oregano (Origanum vulgare) also grow well with geraniums. If the pot is placed near a traffic area, fragrance is released every time someone brushes against the plants.
The space under the geraniums can be filled in as well. The tiny flowers and small leaves of bacopa (Sutera grandiflora) or herb-of-grace (Ruta graveolens) do not detract from geranium flowers. Bacopa spreads out along the bottom of the pot and spills over the edge, draping flowers downward. It is less tolerant of completely dry soil than geraniums and drops flowers when the soil is dry, however it begins producing flowers again when watered. Other low-growing plants to consider are carpet violet (Alsobia dianthiflora) or haircap moss (Polytrichum juniperinum).