How to Grow: Petunia

petuniaPetunia hybrida


Other Name

garden petunia


Sun Requirements

full sun, part sun


Bloom Period and Seasonal Color

Summer to fall in colors including from white, black, yellow, pink, red, blue, purple, bi colors and striped


Mature Height x Spread

6 to 24 inches x 2 to 3 feet


Added Benefits

attracts beneficials, attracts hummingbirds
Petunias are one of the most recognizable annual flowers. They fill garden centers in spring and end up in garden beds, hanging baskets, containers, and window boxes in many yards. There are varieties is almost any color of the rainbow, including some very attractive black flowered petunias which I really think are cool. There are many different types of petunias. Grandiflora petunias feature the familiar, large flowers with single or ruffled doubled petals that grow in a mound, but also can cascade. Multiflora petunias have more, but smaller-sized flowers and are compact growing. Milliflora petunias are the smallest type in growth and flower size. Ground cover types, like the popular ‘Wave Series’,  have sprawling vines that can grow 2 to 3 feet wide.


Where, When and How to Plant

You can start petunia seeds indoors under grow lights 10 to 12 weeks before your last frost date, or purchase transplants from garden centers. Because of the wide variety of petunias available in garden centers and the time involved is starting petunias from seed, it’s often easier to buy the plants in spring. Set out transplants after all danger of frost has passed, in well-drained soil, spaced 6 to 12 inches apart in a full sun location. Petunias can grow in part sun, but won’t be as floriferous.


Growing Tips

Keep plants well watered and fertilize every 3 weeks with an organic plant food. Keep petunias well weeded until the sprawling types, such as the ground cover petunias, can fill in an area.


Regional Advice and Care

Petunias are a low maintenance annual that provide lots of color for your effort. Come mid-summer they may get leggy, especially if not grown in full sun. Simply pinch back the stems to just above a side branch, fertilize, and they will re-grow and bloom again. Many new petunia varieties are self-cleaning, meaning they don’t need deadheading to look great. Older varieties will need periodic deadheading though to keep them tidy. Petunias like cool weather and in warmer parts of New England, may stop flowering in midsummer. Be patient. When it cools, they will return to form.


Companion Planting and Design

Petunias can be grouped together mixing different colors in a garden bed or container. Petunias can also be paired in pots with taller growing annuals, such as geraniums, other cascading annuals, such as ageratum, and attractive foliage plants, such as coleus and dusty miller.


Try These

The ‘Candy Series’ is a multiflora-type that has mounded, 6-inch tall plants. The ‘Picobella Series’ is a milliflora-type with small 1-inch diameter flowers on 8-inch tall plants. The ‘Ultra Series’ is a grandiflora-type with striped or solid colored flowers. The ‘Wave Series’ is a ground cover type with colorful flowers that bounce back well after a rain. ‘Black Velvet’ is a silky textured flowers with almost midnight black coloring.

Excerpted from my book, New England Getting Started Garden Guide.