The USDA Hardiness Zone 5 is the area around Illinois, Missouri, Iowa, and Pennsylvania. Temperatures for Zone 5 drop to a low of -20 degrees F (-26.2 degrees C). Container gardening for decks and patios for Zone 5 will need to be at least hardy to Zone 5a, preferably Zone 4 for best results.
Antirrhinum majus, the botanical name for snapdragon, is a fast growing flower that attracts hummingbirds. Snapdragons are from the Scrophulariaceae, or the figwort, family. A standard in cottage gardening, this makes a great container plant. Flowers are all colors but blue and the plant gets 4 inches to 3 feet tall, depending on the cultivar. Plant a snapdragon in well drained soil in full sun. Propagate via seed.
Solanum melongena, the botanical name of the eggplant, is from the nightshade family. This makes an interesting container plant that will pay you back in eggplants. It will get 2 to 4 feet tall with 9-inch leaves. Purple flowers will become eggplants in various shapes and sizes. Plant one in full sun, watering it every week. Propagate via seed.
Coreopsis grandiflora, the botanical name for coreopsis, is a no-fuss perennial. It is from the aster/daisy family of plants. A coreopsis gets 1.5 to 4 inches tall with 2 to 3 inch wide flowers. Flowers look like daisies in gold or yellow. Expect blooms in June through September. Plant the plant in medium to full sun in dry or ordinary soil. Propagate via seed or by clump division in the spring.
Mentha x piperita, the botanical name of the peppermint, is a fragrant easy-to-grow perennial from the mint family. Leaves are 1.5 to 3.5 inches long with flowers that are tubes of purple and pink. The leaves will smell like menthol mostly, but some cultivars will smell like limes or lemons. Mint leaves can be used as flavoring, potpourri scent, and a variety of other methods. Plant a peppermint plant in full sun or partial shade with good moisture. Propagate via rhizome pieces.
Ruta graveolens, the botanical name for rue, is an evergreen drought tolerant perennial. It is from the citrus family. It can get 2 to 3 feet tall with 3- to 5-inch leaves. The leaves are fragrant when crushed. Small yellow flowers bloom in clusters during summer. Plant a rue plant in hot dry weather, full sun, with regular watering although it is drought tolerant. Propagate via autumn tip cuttings or seed.