How to Care for Grandiflora Petunias

Grandiflora petunias are annuals with showy blooms that grow up to 4 inches in diameter. Some have a trailing growth habit while others maintain an upright form. This makes the plants quite versatile, as they are attractive in beds and borders, planters and hanging baskets. They are available in a host of bold colors and delicate pastel shades. Grandiflora petunias form clumps up to 15 inches tall and add color to the landscape from spring until frost. They do best in full or part sun and require plentiful moisture, especially during the heat of summer.

Garden fork
Organic compost
Spade
Organic mulch
10-10-10 fertilizer
Liquid fertilizer
Pruning shears

Instructions

- 1
  Use a garden fork to loosen the soil 12 to 18 inches deep.
- 2
  Mix a 4-inch layer of organic compost with the soil. Incorporate 10-10-10 fertilizer as well, at a rate of 2 lbs. for every 100 square feet of planting space.
- 3
  Dig a hole equal to the depth and twice the diameter of the grandiflora petunia's root system. Situate the roots in the hole and cover them with the amended soil.
- 4
  Water until the top 6 to 8 inches of soil feel evenly moist. Place 3 inches of organic mulch under the petunias. Avoid resting the mulch against the plant's stems, as this may encourage disease.
- 5
  Water as needed to keep the soil lightly moist.
- 6
  Feed with liquid fertilizer every three weeks, beginning in July. Apply the amount instructed on the fertilizer package.
- 7
  Pinch back scraggly growth as needed to promote fuller foliage.
- 8
  Clip off faded flowers to keep the plants looking tidy and to encourage the development of new blooms.

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