- Petunia hybrid
- Zones A1-A3, 1-45, H1, H2
- Full, Partial Moderate
Low-growing, bushy to spreading plants with thick, broad leaves that are slightly sticky to the touch. Flowers vary from funnel-shaped single blooms to densely double, heavily ruffled ones (like carnations). The many colors available include pure white, cream, yellow, and the whole range of reds and blues: from soft pink to deepest red, light blue to deepest purple. Bicolors and picotees are also available, as are types that have contrasting veins on the petals and kinds with fluted or fringed edges. In most climate zones, plants bloom throughout summer until frost. In Zones 12 and 13, summer heat kills them; in these areas, grow them for winter and spring color.
Plants thrive in good garden soil. Single-flowered kinds are not particular about soil quality and will tolerate alkalinity, but they must have good drainage. Space 8–18 in. apart, depending on plant size. After plants are established, pinch back halfway to encourage compact growth. Feed most kinds monthly with a complete liquid fertilizer; hungry trailing petunias– referred to by growers as the teenage boys of the plant world– do best when given controlled-release fertilizer at planting time in addition to weekly applications of liquid fertilizer. Near the end of the main bloom period, cut back rangy plants by half to force new growth. In humid weather, botrytis disease can damage blossoms and foliage of most petunias; Multifloras are somewhat resistant to this disease. Smog damage (spotting on seedling leaves) and geranium (tobacco) budworm (flowers look tattered or fail to open) may cause problems in some areas.
The following petunia categories are still relevant, but as new hybrids and forms are being developed, some growers are starting to reclassify petunias–especially cutting-grown varieties–by flower size alone, designating them as having large, medium-, or minisize flowers (instead of Hybrid Grandiflora,Hybrid Multiflora, and Hybrid Milliflora). For the petunia relative called million bells, see Calibrachoa.
Hybrid Grandiflora. These hybrid plants bear the largest flowers of all petunia classes but bloom the least profusely. Sturdy plants grow 15–27 in. high and 2– 3 ft. across. Flowers are usually single, to 4 1/2 in. across, with ruffled or fringed edges; colors include pink, rose, salmon, red, scarlet, blue, white, pale yellow, and striped combinations.
Fluffy Ruffles strain has the largest blossoms, growing to 6 in. across. Cascade, Countdown, and Supercascade series plants have a trailing habit that makes them good selections for hanging baskets. Magic and Supermagic are compact, heavy-blooming plants bearing large (4–5-in.) single flowers in white, pink, red, or blue. Other popular strains are weather-tolerant Storm, compact and ruffled Ultra, cascading Cloud, and Hula Hoop and Frost (both with white-rimmed blossoms). –Prism Sunshine– is a much-improved yellow. Double Hybrid Grandifloras have heavily ruffled flowers that come in all petunia colors except yellow.
Hybrid Multiflora. This hybrid group is sometimes called Floribunda. Plants are about the same size as Grandifloras, but flowers are single or double, generally smooth edged, and smaller (to 2 in. across).Neat, compact growth makes them ideal for bedding and massing. Many named varieties in pink, rose, salmon, yellow, white, or blue. Joy and Plum strains have single, satiny-textured flowers in white, cream, pink, coral, red, or blue.–Summer Sun– has bright yellow single blooms. Prime Time and the rain-tolerant Celebrity strains have single flowers somewhat larger than those of the typical Hybrid Multiflora, and flowers in the Whispers series come in more than a dozen colors.
Hybrid Milliflora. These dwarf petunias form mounds 6–8 in. high and wide; they need no pinching or pruning. Plants cover themselves with small (1–1 1/2-in.) flowers that come in all petunia colors except yellow. Effective planted in groups of a single color; very attractive in containers, hanging baskets, and window boxes. Fantasy is a singleflowered seed-grown strain, while Tiny Tunia is a cutting-grown series. Both come in a wide range of colors, and Tiny Tunia even has double forms.
Trailing and mounding petunias. These low, spreading plants (one can cover a 2–5-ft. circle) are used as ground covers and in tubs, in window boxes, and in hanging baskets. There are seed-grown and cutting-grown types. Plants in the seed-grown Wave series grow 6 in. tall, to 5 ft .wide, and cover themselves with 2 1/2 –3-in. flowers of pink, lilac, rose, or purple. The Ramblin– series blooms earlier than Wave, is more upright, grows 3 ft.wide, and comes in the red, pink, burgundy, and lavender range. The Tidal Wave series mounds up to 2 ft. tall if planted 1 ft. apart or against a fence, but mounds just 1 ft. tall if planted 2 ft. apart and given room to spread.
The following cutting-grown types grow slightly lower than the Wave series and spread to 2–4 ft. wide. Surfinias have 1 1/2-in. flowers in pink, violet, purple, blue, yellow, or white. Cascadias are very similar, with heavy bloom and good tolerance of wind and rain. Jamborees are good choices for winter planting in mild parts of southwestern deserts. Supertunias have 2 1/2-in. flowers in shades of pink, violet, or purple; they tend to flower nonstop all summer long. Petitunias bear profuse 3/4-in. blossoms in colors including pink, purple, and white,with darker veins.
Cutting-grown double types such as the Marco Polo series (many colors) and Priscilla (soft lavender with dark purple veins) mound about 6 in. high and spread 2 ft. For a smaller double series, try Sweet Sunshine.close
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