Hardy sunflowers and hibiscus, garden phlox, peonies, Japanese anemones and helenium are good bets. Non-hardy flowers such as dahlias, gladiolas and canna lilies should be dug and stored for winter and replanted. But this is not difficult. Most of these plants need good garden soil and a lot of sun.
There are more kinds of very tall flowers than you might think. Every kind of popular garden flower is available in many colors and sizes. They can be small, medium or large—short, medium or tall. In many cases, a plant that was usually tall, such as iris or daylily, has been bred into short or dwarf forms for the sake of trim, low flowerbeds or for flowers that need no staking. But sometimes they are bred back into unusually tall types.
If someone were to ask how large a hosta plant should be, the answer depends on the variety. The smallest types are only an
inch or two tall and wide, but the largest can have foliage four or more feet tall and be much wider. The flowers rise above the leaves.
Wild plants, too, come in shorter and taller versions. A cold, windy natural situation helps produce a population of smaller
plants that survive by hunkering down in protected crevices, while a fertile prairie setting leads to a group of much taller plants, each trying to rise above the others to get its share of sun.
Well-arranged gardens are all about the right plant in the right place. Tall plants are a natural fit for the back of a traditional flower border, but they also might be just the thing to add drama to a narrow spot against a sunny wall.
Think about the whole plant and how it looks, not just the flowers. Canna lilies, for instance—even the tallest ones—usually have attractive foliage from the ground to the top. That’s not true for hollyhocks. Sometimes their lower leaves go brown just when the flowers reach their peak of beauty. This unattractive feature can be hidden by planting shorter, fuller plants in front of them. It’s nice to have varied textures. Also, with perennials, take the time and duration of bloom into consideration.
Staking is another issue. If a particular flower is top heavy, with too large a flower for the stalk, it is going to need staking. Double-flowered hollyhocks have heavier flowers than single-flowered ones, and they are more apt to fall over.
In 1996, I bought a super-tall daylily cultivar called Hemerocallis altissima and still have it. The yellow-orange flowers are relatively small and light, and the stems are five feet tall, making the blossoms rise like butterflies above everything else. They do not fall over.
There’s an even taller and brighter variety called Hemerocallis altissima “Flyover” and it’s on my wish list. Plus, something in my garden must have crossed with altissima, because I have a peach-colored daylily from seed, with small, wide flowers and very tall stems.
There are large, showy flowers that do not need staking—and hardy hibiscus is one of them. The white, red or rose-colored flowers can be as wide as a dinner plate.
Here is my list of perennials that can add that glamour and dazzle to the garden. It is not a complete one. Plants recommended as cut flowers are usually tall and strong. If your tall beauties need a few years to develop into larger, showier clumps, just add annual sunflowers or tall annual cosmos to temporarily fill in the gaps.
Selected Tall Perennial Flowers:
Asters, chrysanthemums, coneflowers, dahlias, daylilies, delphiniums, foxgloves, hollyhocks, hosta, phlox, sunflowers, verbascum.