Today’s annuals are vigorous growers that don’t require a lot of maintenance, other than watering periodically. The more you water, the more they grow and the bigger they get.
In our trials, we only fertilize each plant at the time of planting with a slow-release fertilizer that lasts through the season. The more you fertilize, the bigger they grow.
I like to grow annuals on the lean side — just enough water and fertilizer to keep them looking good but not overgrown or leggy.
In our annual field trials in Springfield at the Gateway Learning Gardens, we plant in late May, fertilize one time, don’t use any pesticides or mulch, and water only when it’s necessary to keep them growing. And, we don’t deadhead.
Therefore, the plants, in my opinion, are very low maintenance and can be used to brighten up the garden all season.
The Master Gardener volunteers of Clark County make this happen. I couldn’t do this research without their help and I am very grateful for their support. Sally Day, Marilyn Hinderer and Barb Brown are the co-chairwomen of this project.
The following are some of the top performing plants in our trials throughout the years. Please note that due to space limitations, I can’t put all of my favorites, so I had to downsize, highlighting only those at the top of the list. All of these that I selected are for full sun.
For more information about our trials, results from year to year and more photos, visit http://clark.osu.edu/topics/horticulture/field-trials-results.
Alyssum Snow Princess: What was once a cool-weather plant has become the hit of summer. Alyssum has a tendency to fizzle out during the heat of the summer, only to return in the fall when temperatures cool, but this beauty takes the heat of our summers. Growing in a rounded mound, it gets about 2 feet wide and about 6 inches tall. It's great for borders or containers.
Cleome Senorita Rosalita: Rosalita is different from all of the other cleomes because it doesn’t have thorns, keeps its legs covered all season (doesn’t drop the lower leaves) and has beautiful purple blooms that don’t re-seed everywhere in the garden. The plants grow to about 3 feet tall by about 2 inches wide and bloom all summer. It is very drought tolerant and can be used in the center of a large container or in a bed.
Cyperus King Tut and Baby Tut: These two grass-type plants are definitely attention-getters and are quite stunning in the garden or containers. King Tut can grow up to 6 feet tall and about 4 feet wide. Baby Tut grows to about 4 feet tall and 3 feet wide. Both are great centerpieces for large containers and provide great architectural structure and drama in the garden. They also tolerate wet areas and are a great water garden feature.
Euphorbia Diamond Frost: This great filler plant looks just like baby's breath and blooms all summer long with white flowers. The height is about 1 foot by about 1 foot wide. It has tolerated drought as well as wet summers. In a container, it's going to be more airy and weave its way through other plants, providing a nice accent.
Supertunia Vista Bubblegum, Silverberry, and Fuschia: This vigorous series of petunias doesn't stop blooming until a hard frost in the fall and gives masses of color throughout the season. They have a mounding and cascading habit and are good for a massed bed, container or hanging basket. They grow to about 2 feet wide by about 14 to 16 inches tall. These are only three of the many colors that are available in Supertunias; the City of Springfield used these three together for a stunning mix in their hanging baskets downtown in 2010.
Petunia Black Velvet, Pinstripe, Phantom, Pretty Much Picasso: These are petunias that I like to call “boutique” petunias. They are pretty fancy and quite beautiful but not as vigorous in the ground as the Supertunias, Waves and Surfinias. They are, however, beautiful in containers and hanging baskets. In the ground, they grow about 14 inches wide and about 6 to 8 inches tall. From a distance, you aren’t going to be impressed, but up close in a container, you will love the rich color. And with Picasso, how could you not like two colors, green and purple, in one flower?
Petunia Easy Wave Neon Rose, Pink Dawn: Easy wave petunias are great spreading petunias in a variety of colors to use in massed plantings for maximum impact. They grow around 3 to 4 feet wide and about 14 inches tall, mounding in the center. They are good for beds, containers and larger hanging baskets.
Petunia Shock Wave Coconut: The Shock waves also fill out nicely in a mounded habit and are loaded with flowers (a bit smaller than Easy Wave flowers). Coconut had an outstanding, slightly off-white color that really stood out in the night garden. Good for containers, hanging baskets and bedding.
Vinca Titan Icy Pink, Apricot: The Titan series has outstanding large flowers in a variety of colors that bloom all summer. The secret to growing any Vinca is to make sure you don’t plant it too early in cold soils; they get root rot and die. Vinca blooms look like impatiens; however, the plants tolerate full sun. They are rounded, mounded and grow to about 1 foot tall by 1 foot wide.
Zinnia Zahara: The Zahara series of zinnias have great heat and drought tolerance and bloom all summer, without any deadheading. The blooms cover the entire plant and available colors include pinks, oranges, yellows, and double-flowering. The plants grow to about 1 foot by 1 foot and attract bees and butterflies. These plants are great in massed plantings and containers as fillers.
About the Author