Are Petunias Good Border Plants?

Types

• Petunia varieties are divided into four main categories: grandiflora, mutilflora, miliflora and groundcover. Grandiflora petunias have large, single or double blooms that span up to 5 inches across and typically grow to a height of 12 to 15 inches. Multiflora petunias are smaller but produce more blooms and are more tolerant of wet weather than grandiflora varieties. Miliflora petunias produce miniature, tightly compact flowers and are most commonly used as border plants. Groundcover petunias are low-growing and spread quickly, making them a poor choice as a border plant.

Planting

• Select a garden site that gets full sun for your petunias. Plant your petunias in early spring when soil temperatures have reached 60 degrees Fahrenheit. Prepare your garden bed by loosening the soil with a hoe or tiller and mixing in 2 cups of 5-10-5 fertilizer per 10-foot bed. Refer to your fertilizer instructions for exact application rates. Plant your flower bed from back to front, placing your petunias last so that you don't risk treading on them later. Dig holes spaced 12 inches apart to the same depth as the pots your transplants were growing in. Place your petunias in the holes, cover with dirt and water thoroughly to a depth of 6 to 8 inches.

Care

• Water your petunias when the soil is dry -- usually once a week -- to a depth of 6 to 8 inches. If your beds are drying out quicker than you like, lay down a 1- to 2-inch layer of mulch on top of your soil. This will keep water from evaporating and keep water from spraying onto your plants' foliage. Fertilize every two weeks by mixing 2 tablespoons of a liquid fertilizer formulated for flowering plants into a gallon of water and watering your beds with it.

Maintenance

• To keep your petunias looking their best throughout the year, remove any wilted or spent flowers. This will encourage your petunias to produce more flowers and extend their bloom production later into the year. Pinch off stems without any flower buds to the ground to encourage more flower growth and rid your beds of excessive greenery. If your petunias stretch and become to leggy, cut their height by half in mid summer. Always fertilize and water after pruning to encourage new growth.