by Marilyn Odneal, Horticulture Adviser
Petunias are a lovely warm-season summer annual that brightens gardens, containers, hanging baskets and window boxes. Petunias bloom from spring until frost and have a light and lovely scent. They are not fussy and very easy to grow and there are several different types to choose from.
The old fashioned Grandiflora petunias have the largest flowers that may be double or fancy and frilled. Grandiflora petunias benefit from deadheading – removing old dried up blooms. These are also pinched back when they become leggy. Multiflora petunias are more compact with smaller flowers that do not require deadheading or pinching. Floribundas are somewhere between the grandiflora and the multiflora types and produce medium-sized blooms.
Newer types of petunias have come on the scene – the Waves and the Supertunias. The Wave petunia was introduced in 1995 and the Supertunia in 2006. Now there are over 50 cultivars of Wave petunias and 30 Supertunia cultivars. Why so popular? These petunias are low maintenance and are quite large and spreading. Wave petunias do best as ground covers, and in borders, containers and hanging baskets. They are quite vigorous and may crowd out other flowers. Supertunias are best for hanging baskets since the stems can grow to 3 feet in length. Both types need to be watered and fertilized regularly since they are so vigorous. Although the Waves and Supertunias do not need to be dead headed like the Grandifloras, you might consider rejuvenating them in midsummer for a more compact plant and a new crop of flowers.
My Bubblegum Supertunia in a hanging basket has been very beautiful so far this year. Now the plants have become leggy and the basket a bit lop-sided. Around the 4th of July, this type of petunia in a container or hanging basket needs a little boost to rejuvenate it.
Rejuvenating Wave and Supertunia types of petunias in hanging baskets involves cutting back one-half of the stem so the flowers are removed and the stem with green leaves remains. This is not for the faint hearted, since it is difficult to cut the flowers off to leave just the stems. But be strong – soon new flowers will appear and the plant will be more compact and lovely. After you cut them back, remember to water and fertilize the plant to promote new growth.
So cut back your leggy hanging basket petunias and give them a new lease on life. Although it is hard to cut off all of the flowers – you will be rewarded with more blooms in the future. Remember, you can always put your cut flowers in a vase to brighten up the house and ease the pain.
Direct comments or questions concerning this column to Marilyn Odneal via email at MarilynOdneal@missouristate.edu; write to Missouri State Fruit Experiment Station, 9740 Red Spring Road, Mountain Grove, Mo. 65711; or call (417) 547-7500. Visit our website at http://mtngrv.missouristate.edu.