Why are my petunias leggy?

Legginess is the natural trajectory of petunias without intervention — stems extend from the growing tip while lower leaves die back, leaving long bare stems. The causes include: not pinching at transplanting, not deadheading regularly, insufficient sunlight, and not performing a mid-season cutback. The fix for already-leggy plants is a hard cutback to 4–6 inches followed by fertilizer and water. Per University of Minnesota Extension, most leggy petunias recover vigorously within 2–3 weeks after a hard cutback.

Why are my petunias not blooming?

The most common reasons: insufficient light (less than 6 hours of direct sun), nitrogen-heavy fertilizer that promotes foliage over flowers, or the plant has set seed and slowed down. Deadhead spent flowers at the seedpod, switch to a higher-phosphorus fertilizer, and ensure adequate sunlight.

Can I save petunia seeds?

From straight species petunias, yes. From modern hybrids (which is almost everything sold), the offspring will not breed true to the parent plant. Seeds from a Wave or Supertunia will produce variable seedlings that may not share the parent's characteristics. It's simpler and more reliable to purchase new transplants each spring.

How do I overwinter petunias?

Take 4-inch stem tip cuttings in September, root in moist perlite or water, and grow under bright indoor light through winter. Rooted cuttings can be pinched back in late winter to promote branching and moved outdoors after the last frost. This works well for unusually vigorous or distinctively colored plants worth preserving. Most gardeners find it simpler to buy fresh transplants annually.

Are Wave and Supertunia petunias the same?

No — Wave is a PanAmerican Seed brand, Supertunia is a Proven Winners brand, and there are other spreading petunia series from other breeders. They all share the general spreading/trailing growth habit and self-cleaning characteristics, but they are different cultivar lines with slightly different growth habits, branch angles, and disease tolerance profiles. All require the same general care.

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Species guide

Petunia Care: Deadheading, Watering, and Why Yours Got Leggy

Why Petunia × hybrida plants go leggy by July and how to cut them back for a second flush — plus watering, fertilizing, and choosing between grandifloras, multifloras, and spreading types.

By Thomas Joseph Published 2026-06-11 Updated 2026-06-13 Reviewed by Thomas Joseph 8 min read

Purple and white petunia flowers spilling from a hanging basket in summer sun — Photo: Unsplash

Which petunia type are you growing?

Modern petunia breeding has produced several distinct categories with meaningfully different care needs and performance characteristics.

Grandifloras

Large flowers (4–5 inches across) on upright plants. Showiest individual blooms, but the flowers are damaged by heavy rain and the plants are most prone to becoming leggy. Best suited to sheltered locations like covered porches or protected beds. Per University of Minnesota Extension, grandifloras are "best in areas protected from rain."

Multifloras

Smaller flowers (2 inches) in much greater abundance on more compact plants. More rain-tolerant and more vigorous than grandifloras. Most growers find multifloras outperform grandifloras in open garden beds exposed to weather. 'Celebrity' and 'Carpet' series are common multifloras.

Spreading and trailing types (Wave, Tidal Wave, Supertunia)

The most popular modern petunias. Spreading types like the Wave series grow 6–18 inches tall but spread 3–4 feet wide, producing a solid mat of color. They are self-cleaning (no deadheading needed for continuous bloom) and more heat-tolerant than older types. Per University of Minnesota Extension, "spreading petunias spread more than 3 feet" and are excellent for large containers, window boxes, and ground-cover use in beds.

Millifloras

Tiny flowers (1 inch or less) in extreme abundance on compact plants. 'Fantasy' and 'Picobella' series. Very heat-tolerant and low-maintenance. Best used as edging plants or in combination containers.

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