To create a very simple yet powerful landscape display using petunias, you can pair plants with contrasting heights and colors, like the example below of 'Supertunia Vista Silverberry' and Pennisetum 'Vertigo' grass. The light and dark together are very striking, plus the plants have very different textures and growth habits. When planted in a big group, there is a more intense affect than if the plants had been spaced out alternately in the plot.
For something unique you can try 'Sophistica Lime Bicolor' where no two flowers are exactly alike.
Care and maintenance
In western Kansas the soils are often alkaline (high pH), which can cause some petunias to suffer from iron chlorosis. This yellowing of the leaves is a result of the plants not taking in enough iron due to the soil pH. Since there are also annual flower trials at the K-State Agriculture Research Center in Hays, we are able to observe which varieties are most resistant to iron chlorosis. We recommend cultivars like the Tidal Wave series, Shock Wave series, and Supertunias that are on the Prairie Star list. If you suspect your soils have a high pH, get a soil test and consider adding soil sulfur as recommended.
With petunias, maintaining your fertilizer program throughout the summer is very important to keep the plants blooming. As is discussed in the FAQ section, here is our recommendations on fertilizing annual flowers:
Simply put, annuals bloom on new growth. The stem of the plant has to grow a little longer to make room for the next flower. If there's no new growth, there will be no flowers. So you need to give the plants frequent light applications of Nitrogen (N). But be sure to avoid excess - that will lead to all green growth and no flowers. Like everything in life, a little is good but too much can quickly turn harmful. It is also important to know that Phosphorus (P) does not influence flowering. Fertilizers with levels of Phosphorus higher than the amount of Nitrogen should be avoided. An ideal fertilizer for flowers should have a nutrient ratio of 2-1-1 or 3-1-1 (N-P-K) such as 12-4-4
Find a full list of recommended petunias and other annual flowers on the Prairie Star list, including ones that are best in containers.