Geranium or Pelargonium

Tender perennials grown as tender annuals north of Zone 8, these are the much loved bright geraniums seen on windowsills, on terraces and in gardens everywhere. Most are varieties of Pelargonium x hortorum (zonal geranium), which forms a large, shrubby plant in frost free climates but grows about two feet tall in colder ones. The large flower clusters can be red, pink, salmon, orange or white. Martha Washington geraniums (P. domesticum) are shorter, with pink, red or white flowers. The flowers in each cluster are large, rather like those of azaleas, often with a blotch of a darker shade. Ivy geranium (P. peltatum) is a trailing plant often used in window boxes. There are also a number of species grown less for their flowers than for their leaves; these have various scents such as apple and lemon and are popular in herb garden. 

Well, if you want to grow Geranium then seeds can be sown indoors in later winter or early spring in soil kept warm for better germination. Growing from seed can be slow, and therefore several gardeners prefer to buy a few plants the first year, and then take cutting each year for next year crop or for a supply of bright houseplants in winter. On the other hand, growing from seed is apt to produce plants that are free from the diseases that cause leaves to yellow. These diseases may be carried over if geraniums are propagated from cuttings. Seeds of a number of hybrids are now available. 

Geraniums are warm weather plants and relatively drought tolerant, but intense heat can be fatal to them, and cool nights are best. Martha Washington geraniums need a period of cool weather to bloom and thus are not satisfactory for hot climates. All like full sun but can take a bit of shade, especially in hot areas. Plant in not overly fertile as well drained soil, 12 to 15 inches apart in the garden. Cut them back to half their height in later winter or early spring in climates where they are perennial. Give pot grown geraniums plenty of light so they will not be leggy. Often a large pot with several plants looks best. 

 Source: Charismatic Planet