8/2/2019 Petunias in the Garden

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Cooperative ExtensionEdith Wallace, Ph.D., Master Gardener, Passaic County

Elaine Fogerty Barbour, Passaic County Agricultural Assistant

Fact Sheet FS11

Petunias are, or should be, a mainstay o every garden. They come in many hues and can brighten up an area with their vibcolors. Gardens need annuals to provide blossoms and color throughout the summer and petunias ft this purpose admirab

Dependable and versatile petunias have been a avorite o gardeners since their introduction rom South America to Europegardeners around 1825. Most o the superior hybrid varieties have been developed in the United States. The new cultivars tare hybrids o several petunias species perorm so well that there has been a resurgence o interest in these plants.

Petunias may be used in hanging baskets, window boxes, containers, borders, or beds. They will bloom abundantly in ull to partial shade; a minimum o 6 hours per day o sun is required or good owering. Choose a site with good drainage, asthey do not like dry or wet soil. Incorporating compost, peat moss or composted manure can improve the soil structure.

Petunia cultivars are divided into general groups. Grandiora petunia owers are large, 4 to 5 across, ewer in number, an

susceptible to rain damage so they grow better in containers sheltered rom the rain. Some grandiora varieties have doublowers. They have trailing stems and tend to spread twelve to fteen inches. Multiora petunias have smaller owers, 2 toacross, in great quantities. They are more tolerant o wet weather and make good bedding plants. New cultivars are introdueach year so read the label careully to suit the type o petunia to the situation where it is to grow. Compact miniature petucall miniora produce 1 owers that are appropriate or hanging baskets and containers. Groundcover petunias are lowgrowers, only around 6, but they ower along the stem. These spreading petunias are used as colorul groundcovers and inhanging baskets and window boxes.

Petunia seeds may be started indoors 10 to 12 weeks beore the last rost date. They are extremely small and may bedistributed evenly i mixed with fne sand or purchased as pelleted seed. It is easier to purchase nursery-grown stock. Petunmay be planted outside ater May 15 in most areas o New Jersey to avoid injury rom rost.

Petunias are heat tolerant plants and do not require a lot o water. A deep watering to a depth o 6 to 8 once a week issufcient or most petunias. In containers petunias will need more requent watering. Hanging baskets may need to be wat

daily, depending on the type o container and potting mix.Fertilization o petunias growing in garden beds should be based on soil test results to reach ull owering potential. Fertilat planting. The ertilizer can be supplemented later in the summer i needed. Petunias preer a pH o 6.0 to 7.5.

Petunias will ower all summer until rost. They may be deadheaded (remove owers that have fnished blooming) to keepcontinuous bloom. It is easier to wait until they become leggy and then cut back by hal, or i low plants, cut back to 6. Newgrowth will branch rom the base.

Pests o petunias include tobacco budworm and tomato hornworm that may be hand removed or treated with an appropriainsecticide. Common disease problems include powdery mildew and botrytis. Properly spacing the plants so that air cancirculate and avoiding overhead watering can discourage these diseases. Fungicides can be used according to product labelsprevent the diseases rom spreading.

As petunias are perennials in their native South American habitat, consider potting up plants or winter bloom in the homeTo propagate avorite varieties, root 6 stem sections in sand.

Petunias In The Garden

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