Petunias thrive with little care other than watering and a bit of fertilizer now and then. They are annuals, so don't expect them to last more than one growing season. Cut them back if the plants get leggy or stop blooming, and it will encourage a new flush of growth and flowers. Grow petunias by themselves or combine with other flowers.
Petunias have a mounding growth habit and reach 18 inches high. The 3-inch-wide flowers spill over the sides of a hanging basket in wild profusion. Choose other flowers that have a vigorous growth habit as well or they'll be overwhelmed by the petunias. Calibrachoa has a low trailing habit and flowers abundantly. The flowers look like small petunias. Verbena trails as well. The small clustered flowers bloom in pinks, purples and white. Bacopa is another choice. It trails to 24 inches and has either white or blue flowers no more than 1/2 inch wide.
Choose flowers that thrive in full sun and warm weather. In hot weather, petunias stop blooming as profusely. Edge a bed of mixed blue colors of petunias with candytuft to set off against the blues. Candytuft grows to 12 inches and is covered with small white flowers. Red salvia with orange dwarf zinnias and yellow petunias are a fiery combination for the garden. Create a flag using rows of red, white and blue petunias edged in bright blue lobelia.
Petunias are well suited to container growing. Check the containers daily to see if the soil is dry. During windy, warm days, containers dry out more quickly than garden soil. Contrast the trailing habit of petunias with flowers that grow upright such as snapdragons and stock. Fill in with pansies for a late spring-themed container. If you prefer summer flowers, choose lantana, grown as a perennial in warm winter areas but as an annual elsewhere, and purple coneflower to stand above the petunias.
Raised beds solve the problem of poor drainage and soil since you fill the beds with potting soil or topsoil. Edge a raised bed with petunias to soften the sides of the bed and add color. Place miniature roses in the center of the raised beds so the flowers may be enjoyed closer to eye level. Mix the petunias with flowering vegetables such as tomatoes with yellow flowers and eggplant with purple flowers. The ripening vegetables add even more color to the raised bed.