Petunias are commonly cultivated flowering plants that are shaped similarly to funnels. They are a genus that originates in South America, and are part of the Solanaceae family. Petunias come in many different colors, which include purple, yellow, white, red, pink and bicolored. The flowers are annuals and can reach between 12 to 18 inches in height.
Petunia seeds need to be cultivated outside on the surface of soil after the spring's last frost. They should be grown in parts of the garden that have full sun or partial shade. The flowers prefer moist soil. During sowing, it is beneficial to add organic matter to the soil. The pH level should be between 6 and 7.5. They can be cultivated in all of the U. S. Department of Agriculture's (USDA) zones in the country.
It is important to take care of petunias to keep them growing healthily. To keep the flowers healthy, their tips should be pinched back, which promotes branching and therefore makes the plant appear bushier. It is crucial to keep petunias well watered, as they thrive in moist ground. Once the petunias are doing well, it is important to fertilize them and do so once a month. Toward the end of summer, the entire plant needs to be cut back in half, which could lead to another bloom.
Petunias are generally free of diseases. In some cases, however, damping-off can be a big problem with petunias. It can result in the seeds becoming rotten during the germination process, or the seedlings dying post-emergence. This can be avoided with proper sanitation and keeping the appropriate temperature and moisture. Viral diseases are also possible and can result in destroyed foliage that is stunted. Discoloration of flowers is another possibility, as is flower deformity. Other potential diseases include crown rot, alternaria blight, botrytis, fusarium wilt and fasciation.
Pests are also rare for petunias. In some situations, however, cutworm and aphid infestations are possible with petunias. The best way to avoid these infestations is by keeping the petunias strong and healthy, making them less susceptible to insects.
There are two general categories of petunias: the Multiflora and Grandiflora classes. Multiflora petunias are known for growing compactly and having more numerous, yet tinier blossoms. They also can handle hard and aggressive wind and rain better than the other class. Grandiflora petunias have bigger but fewer flowers.