Hollyhocks, or Alcea rosea, are technically biennial, meaning that they take two years to complete their life cycle; however, they are also self-seeding plants that replace themselves very effectively, so once you plant a few, you should see them return every year in the same spot [sources: Texas Cooperative Extension; Roberson]. Hollyhocks can grow 6 to 8 feet tall, so they are often staked or planted next to a high fence or wall [source: Midwest Gardening].
Hollyhocks bloom from June through August, and their bright colors and deep flowers attract butterflies and hummingbirds. Unlike drought-tolerant perennials like yarrow and stonecrop, hollyhocks like lots of water and do best in well-drained soil. Hollyhocks are found in an assortment of colors including white, yellow, pink and red, and they work well in both fresh and dried bouquets. They are able to tolerate both high and low temperature extremes, with most varieties flourishing in zones two through eight and some growing best in zones three through nine.
The next perennial may just be the polar opposite of hollyhock in terms of its appearance, but it's a great addition to any Midwest garden.