How to Select and Care for Petunias

Select the wave petunia for hanging baskets, window boxes, groundcover or in pots. They grow up to 6 inches tall and spread vastly. Single petunias have single flowers, and double petunia as the name suggests have double petals. The tidal wave petunia grows into a thick bunch of flowers up to 22 inches tall, and the rambler petunia which grows up to 10 inches high and spreads well.

Wait until all chance of frost has passed to plant the petunias outside. They can be planted in the ground about 10 to 15 inches apart in groups. You can also plant them around mailboxes, utility boxes and trees, along the curb and anywhere that needs color. Hanging baskets and pots look attractive with petunias planted closely together. Wave petunias need more room and do well as a ground cover planted about 1 ½ feet apart. They like full sun with minimal shade but can be in shade if they get at least six hours of sunlight.

Plant the petunias in sandy, fertile soil that drains well. Place organic mulch such as wood chips on top of the soil and add slow-release fertilizer.

Water petunias often, given their shallow roots. They can dry out quickly in high heat, so they may need watering twice a day. Continue with organic fertilizer diluted to half-strength once a month sprayed on them or poured into the soil.

Pinch back the main stems slightly when plants are small to force them to grow more side stems and bush out more fully. Pinch off the dead flowers to keep them looking good.

Cut each stem back about halfway if the petunias start to get long, leggy stems and look scraggly. This pruning stop blooms for three to four weeks, but the plants bounce back nicely.