Scientific Name: Petunia × hybrida (Hook.) Vilm.
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Recommended Temperature Zone:|
sunset: All zones
USDA: All zones
Frost Tolerance: Semy hardy in Phoenix, but killed by summer heat
Heat Tolerance: Killed by the summer heat in Phoenix
Sun Exposure: Full sun
Origin: South America
Growth Habits: Tender perennials grown as half-hardy annuals, up to 12 to 24 inches high (30-60 cm), 12 to 24 inches in diameter (30-60 cm)
Watering Needs: Regular water, good, well drained garden soil
Petunias are generally classified in 3 categories:
Petunias are largely used in flower beds. They can be used by themselves, or as accents with other annuals and perennials. Petunias are also great container plants.
Grandifloras have very large flowers, up to 5 inches in diameter (12 cm). They are generally grown in containers because the flowers are rather fragile.
- Floribundas have 3 inch flowers (8 cm)
- Multifloras have large quantities of durable 2 inch flowers (5 cm)
Petunias make wonderful flower displays in Phoenix too, the main difference with the rest of the country is that in Phoenix, they should be planted in the fall. They grow slowly during the winter and bloom heavily starting at the end of February. In Phoenix, they start failing in May, and should then be removed to leave space for summer annuals.
Petunia seeds are small and difficult to handle. It is probably simpler to buy already grown plants. If you decide to go ahead and start seeds in a warm place at 70 to 85°F (21 to 29°C). Plant 8 week old seedlings 12 inches apart (30 cm). In colder winter areas, plant the petunias after the last frost date. Remove spent flowers to promote rebloom.