These Plants Sing Their Hearts Out from the Back Row of a Garden Choir

 Big and Bold Plants for the Back of the Border

There are some similarities between a garden and a chorus, lots of different plants or lots of different voices coming together to create something beautiful. If all the plants or voices were the same, the effect would be, to say the least, very dull. Every element, plant or voice has something to contribute. Just as you need sopranos or basses to make a song sound right, you need big and bold plants to make a garden border look right. The following plants are some of my favorites for adding that perfect bold note to a garden setting. With a few choice plants, a garden can go from being a warm-up act to being the star of the show.

1. Ricinus communis* ‘Zanzibarensis’

You won't get much bolder than castor bean, and the biggest and boldest of the bunch is 'Sanscipherensis'. Unlike the popular burgundy cultivars, this monstera plant has leaves in shades of blue-green. The palmate leaves are 2 to 3 feet wide, and the plant’s truly sturdy habit can reach 10 feet tall or more. Full sun will produce the best growth. It blooms in upright clusters that produce decorative, spiky, red seed pods. I should point out that castor bean is poisonous. Make sure children and pets don’t eat the seeds, and cut off the seed pods if there’s any cause for concern. Castor bean seeds readily in warm weather, so they’ll come back almost every year. It’s a true tropical, hardy only to frost or a frost, so saving seeds is a must if you want plants in colder zones every year.

2. Catalpa pycnoneoides ‘Aurea’

If you love trees but don’t have room for a whole tree, sometimes you have to get creative. For example, I love the big yellow leaves of the 'Aurea' Southern Catalpa, but I definitely don't have room for a 30-foot tree in my front yard. My solution was to plant one early each spring and prune it back to 3 or 4 feet. It responds by putting out a ton of bright acid-yellow new growth on branches that reach about 6 feet tall in a season. It's beautiful and doesn't take over the entire garden. Hardy in most parts of the country, 'Aurea' could be a bold choice for one of your beds.

3. Canna ‘Flaming Kabobs’

All cannas are wonderful, and I find them especially wonderful when they're large. 'Burning Kebabs' canna is a tall beauty that offers both magnificent foliage and spectacular flowers. Its 5- to 6-foot-tall stems have large, gray-green leaves that are edged in a bright yellow that stand out against the blue sky of summer. 'Flaming Kebabs' is a vigorous grower, so a small clump planted in mid-spring will grow into a large clump by fall. I'm not the only one who enjoys the brightly colored flowers; hummingbirds can be seen hovering around the plants all summer long. For the best display, give it full sun, rich soil, and ample moisture. Cannas are easy to overwinter in colder zones if you dig them up after a frost.

4. Napaea dioica

I came across Glade Mallow by chance at a large perennial nursery. I'm always looking for large, tropical-looking, hardy plants, and Glade Mallow's thick, maple-shaped leaves caught my eye. The leaves are 18 inches long and wide at the base of the plant, tapering in size as you move up the tall stems. The plant will be adorned with small white flowers for several weeks in early to mid-summer. It will tolerate full sun in very moist or wet soil, but I usually place it in a spot with bright shade or less direct sunlight to keep the soil from drying out too quickly, as it can look scraggly in dry conditions. Since Glade Mallow grows quite tall, some protection from the wind is helpful.

5. Musa 'Siam Ruby'

In my top three banana choices, I have to add 'Siam Ruby', which has red leaves on a yellow-green background. There are other bananas with burgundy on the leaves, but the color doesn't compare to the intensity and red factor that 'Siam Ruby' displays. This one is truly unique. It's a small banana that doesn't get much taller than 8 feet. Good, moisture-retaining soil with plenty of organic matter and full sun will produce the best growth and color. Like most bananas, it's truly tropical, so if you're planting in a location colder than zone 9, you'll need to dig it up in the fall. It's easier to get through the winter than the summer - just pot it up after the frost and then store it dormant until spring. On the other hand, 'Siam Ruby' isn't that expensive, so you can just leave it alone and buy a new one next year.

6. Silphium terepintheum

Prairie dogwood gives us the boldness of a tropical plant native to the prairie. The basal cluster of leaves reaches 3 feet wide and is made up of toothed leaves that are 18 inches long and 12 inches wide. These are punctuated by bare stems of yellow daisies that reach 10 feet tall in the summer sky. It is very pretty. Full sun is a requirement, and the better the soil, the larger the plant. However, a plant this tall can have some problems with strong winds. It helps to include it in a community with other tall perennials and woody plants that help it stand upright.

7. Vernonia altissima 'Jonesboro Giant'

In the Midwest, pastures and abandoned fields turn purple in late summer with ironweed flowers (Vernonia spp. and cvs., zones 4–9). While these plants often grow 6 to 8 feet tall, that's not enough for some of us. We need skyscraper-level plants like 'Jonesboro Giant' ironweed, which can reach 12 feet tall. While it's highly adaptable to a variety of growing conditions, it does require consistent moisture to reach those mesmerizing heights. Dark green leaves adorn tall, upright stems, making this plant attractive long before its jewel-toned purple flowers appear.