Zone 5 is split into zone 5a (-20 to -15 degrees F)--the area around Des Moines, Illinois and Iowa--and zone 5b (-15 to -10 degrees F), which is around Columbia, Missouri and Mansfield, Pennsylvania. Plants in these zones must be able to withstand cold temperatures. Perennial seeds good for the Zone 5 area can include plants that are about to germinate in these types of conditions.
Swamp Mallow, or Hibiscus moscheutos, is from the Malvaceae (mallow) family. It is a perennial that gets to 7 feet tall, with 2- to 3-inch-wide, velvety leaves. Flowers are 6 inches wide in white or pink. Plant a swamp mallow in full sun with regular water. Propagate via seed or by division of roots. This will die down come winter but will come back in the spring season.
Scarlet Hibiscus, or Hibiscus coccineus, is from the Malvaceae (mallow), family. It is a perennial shrub that gets to 7 feet tall with 6- to 8-inch-wide flowers in red. This will die down come winter but will re-grow in the spring season. Plant a scarlet hibiscus in full sun and moist soil. Propagate via root division or seed (scrape seed or puncture before planting).
Coreopsis, or Coreopsis grandiflora, is from the Asteraceae/Compositae, or aster/daisy, family. It is an easy and fast growing perennial that will attract butterflies. This will get 1 to 4 feet in height with 2- to 3- inch-wide flowers that are yellow to gold. Flowers bloom June to September. Plant a coreopsis in medium to full sun in ordinary soil. Propagate via clump division in spring or by seed.
Foxglove, or Digitalis purpurea, is from the Scrophulariaceae, or figwort, family. It is a short-lived perennial. Leaves are 5 to 10 inches long with flowering stalks of 3 to 5 feet tall. Tubular flowers are 2 inches long in yellow, white, cream, pink, purple or lavender. Flowers bloom late spring to early summer. Plant a foxglove in moist acidic soil in partial shade with regular watering. Propagate via late summer or fall seed sowing.
Common Yarrow, or Achillea millefolium, is from the Asteraceae/Compositae, or aster/daisy, family. It is a perennial that attracts butterflies. Stems of yarrow get 1 to 3 feet tall with a plethora of very small flowers. Leaves are grayish-green, fragrant and feathery. Plant a yarrow plant in poor soils in full sun with regular watering. Propagate by spring or fall division, or by seed.