There are times when only a tall and stately perennial flower will do the trick in the perennial garden. When island beds are suspended in huge spaces, or when tall fences back perennial borders, something tall is need to balance the bed. Using tall, herbaceous perennials in these situations can help bring visual order to your garden.
Defining Tall Perennials
There are many perennials that reach heights of two to three feet, especially if older varieties are selected. But to truly make a vertical accent, a perennial needs to be taller than three feet. Many of the tall perennials are grown more for their vertical form and foliage than for their flowers, but some tall and stately perennials are also beautiful in bloom.
In many species of plants there are varieties that reach different heights. The trend today is to breed plants that are more compact. When searching for the true queens of the garden, you may need to look for older or heirloom varieties. If you want height, don't assume a certain plant will be tall. Check the label or description to be sure.
The height of plants can also be determined by growing conditions. Some tall plants need full sun to grow their tallest, while others will turn out shorter and more compact in full sun. Some need a warm, moist, long summer to reach their ultimate height. Soil fertility will also determine height. In general, the more fertile the soil, the larger a plant will grow.
Tall Perennials for Shady Spots
Some astilbes can grow quite tall in moist shade, and their early summer flowers are a bonus. The leaves are fern-like. Astilbe taquetti (upright plumes) and Astilbe thunbergii (arching sprays) are more likely to have tall cultivars. Aruncus, or Goats Beard, is similar to astilbe but with coarser leaves. It has white, plume-like flowers in early summer and prefers moist soil.
Cimicifugia, or Snakeroot, is a true tall and stately perennial. Most garden varieties have purple-black foliage and fragrant spikes of pink or white flowers in summer. They can grow four to five feet tall.
Thalictrum, or Meadow Rue, will grow in partial shade in the South but likes more sun in the North. It has small leaves and lends an airy, light look to the perennial bed. In early summer, sprays of pinkish-purple flowers that are lightly fragrant will appear.
Hardy hibiscuses can reach tall heights in partial shade or partial sun as long as the soil is kept moist. These are best for gardeners who love flashy flowers. The plants are slow to grow in the spring, but once it gets warm they zoom up to four or five feet. In late summer they are covered with dinner-plate-sized flowers in shades of pink, red, lavender and white. There are varieties with dark foliage and cultivars that have broad, impressive leaves good for hiding fences from view.
Ligularia will grow in partial shade or full sun if it's kept moist. It has large, toothed, heart-shaped leaves with a purple underside and spikes of small yellow flowers in summer (L. stenocephala, "The Rocket") or yellow daisy-like flowers (L.dentata).
Stately Perennials for Full Sun
One of the best ways to get height in full sun, if you've got plenty of room, is to plant ornamental grasses. There are numerous varieties of Miscanthus, Panicum, Pennisetum, Calamagrostis, Cortaderia and other grasses that reach truly impressive sizes. They may take a few years to make large clumps. Many of these grasses have attractive flowering plumes and can lend winter interest to the garden if you don't cut them back at the end of the season.
Remember that these grasses get tall and wide. Plan to spend some time cutting them back or dividing them at the end of each growing season to keep them under control. Check the zone requirements to see which varieties are hardy for your zone. If you live in an area prone to fires, ornamental grasses should not be planted close to the house.
For old-fashioned splendor, hollyhocks and delphiniums may provide the height you need. Hollyhocks come in double- or single-flower varieties and in many colors. They bloom for a long period in the summer.
Delphiniums bloom in early summer in a wide range of colors, including true blue. They prefer areas where summers are not hot and humid.
Verbascum, or mullein, has rosettes of soft, fuzzy gray-green leaves and tall spikes of flowers in late summer. The variety "Caribbean Crush" is a gorgeous blend of raspberry-, orange- and lemon-colored blooms.
Many lilies are quite tall and are stunning when in bloom. Lilies like to grow up through lower plants to keep their roots shaded. Some lilies will perform well in partial shade. Most lilies have large, trumpet-shaped blooms in mid to late summer. Many are fragrant enough to perfume the whole yard. Tall lilies include most Oriental varieties and Oriental hybrids, Lilium formosanum, Martagon lilies and Lilium lancifolium, which includes Tiger Lilies.
Other tall plants that may be hardy in warmer zones include cannas, dahlias and Alocasia, or Elephant Ears. In colder zones, you may need to dig these plants up and store them in a warm, sunny area during the winter.
Cannas have flowers but are usually grown for their huge leaves. Many variegated-foliage varieties are on the market. Elephant ears are also grown for their huge leaves.
Dahlias are grown for their flowers, which come in a wide variety of colors and forms. Some also have attractive foliage. Make sure to select tall varieties.
For dry areas, some tall plants to try are Agastache, Hesperaloe and varieties of yucca. A tall native plant that is good in butterfly or wildflower gardens is Eupatorium, or Joe Pye Weed, which has clusters of tiny pinkish flowers in late summer. It prefers moist sites but will adapt to average garden conditions once it's established.
For truly impressive size, the banana Musa basjoo is hardy to Zone 7. It can be dug and wintered inside in cooler zones. Another tropical stunner, this plant grows stalks up to 12 feet high topped with broad and impressive leaves. It will produce pale yellow blooms throughout the year as long as the inedible fruit isn't allowed to set.
Spring flowering bulbs exuberantly herald the end of winter with bright blasts of color like fireworks in slow motion. When we squirrel away these gems in the fall, we almost forget about them. Then they pleasantly surprise us as they emerge the following spring when everything else is still drab and barren.
Tall perennials play a number of roles in the landscape. A tall perennial makes a great accent plant, calling attention to itself as it towers over the garden. A mass of tall perennials makes the perfect backdrop for a well-designed bed. Tall perennials are also perfect for covering bare walls or fences. Tall perennials can also form natural screens or borders to create private outdoor spaces.
If you are interested to know how to prepare your garden bed for annuals, don't worry it is not a difficult task and you will find it very easy and interesting job. It requires a little art and creativity to have blooms in your garden bed with a variety of colors such as pink, red, orange, purple and yellow.
Flower shows are an invaluable resource for gardeners, from the novice to the most experienced.