I love a layered look in the garden. One that’s filled with different colours and textures. And that means you need different heights, from the tall perennials in the back, to the smaller, mounding plants or groundcover in the front. Picture a public school class photo where you have the smaller kids in the front on chairs, a middle row standing and the tall students in back, maybe up on a bench. The point is you get to see the faces of all the kids, so you want to make sure you see all the plants.
Why choose tall perennials for the garden?
Tall perennials not only add depth and shape to a garden, when included among plants of other heights, they can camouflage things you might want to hide, like a chainlink fence or an air conditioner. They can even add a bit of privacy.
When choosing all of the plants for your garden, no matter what the height, try to select a variety based on bloom time, so there is always something flowering from spring through fall.
Avoiding pitfalls from planting tall perennials
When choosing a tall perennial, consider the size of the garden, the surroundings, and the other plants involved. You want to make sure you achieve balance. Rather than one tall plant sticking out among the shorter-statured plants in the garden, plan your composition. Consider planting in odd-numbered drifts.
Read your plant tags carefully. They’ll indicate both the eventual height and the spread of your plant. Leave space accordingly, even though it may not look great at the time. The key is to be patient for that eventual lush and full look you are trying to achieve. But you’ll have to contend the gaps as you wait for your plants to grow in their designated space.
Be mindful of where the light is coming from, as well as scale. You don’t want to shade out shorter perennials by casting giant shadows with your tall perennials.
Have plant stakes at the ready. Some especially tall plants can flop. Make a plan to hold them up before everything fills in. It’s possible other plants could also fill this role.
My list of some favourite tall perennials
I refrained from including the most successful tall plant in one of my gardens this past summer: goldenrod. One area had a pretty stunning cascade of yellow blooms—covered in bees!
Height: Up to five feet (1.5 metres) tall
I enjoy the fiery burst of colour at the end of red hot poker (aka torch lily) stems. These low-maintenance perennials are hardy down to USDA zone 6. Apparently the deer and rabbits don’t like them either. Plant them in a sunny spot in well-drained soil—their crowns object to wet soils and can rot. As far as placement, select an area where those torches will really stand out!
Height: Three to five (.9 to 1.5 metres) tall
Russian sage is one of those plants where the flowers are so small, that all together they look like a lavender cloud floating in the garden. This is an unfussy plant. It’s heat and drought tolerant, doesn’t mind poorer soil, and the blooms last for weeks. It also smells good. Though it won’t spread, some varieties can grow up to two feet in width, so plan accordingly.
Height: Three to four feet (.9 to 1.2 metres) tall
Crocosmia is a summer-blooming bulb with these beautiful, arching, conical bursts of flowers at the end of their long stems (which the pollinators love). They enjoy full sun to partial shade. Planted in the spring, these summer-flowering plants are hardy down to zone 4. Have patience as it can take the plants, which are a member of the iris family, a couple of years to become established.
Bear’s breeches (Acanthus mollis)
Height: Up to three feet (.9 metres) tall
Bear’s breeches is a hefty plant. The flower spires themselves can reach up to three feet tall. Purple bracts shelter white blooms. They are hardy down to USDA zone 6 (or maybe 5 if they’re in a more sheltered location). Plant in full sun to part shade in an area with well-draining soil.
Height: One to four feet (.3 to 1.2 metres) tall
I first discovered lupins growing all along the side of roadways on Prince Edward Island in my early 20s. In that province, they’re actually considered a weed and invasive species. But now, to me, these are a quintessential English cottage garden flower. They were in several show gardens at the Chelsea Flower Show when I went a few years ago, usually planted among some equally stunning, wispy, showy foliage. Plants prefer full to part sun and don’t do well in heavy, wet soil.
Height: Three to five feet (.9 to 1.5 metres) tall
Rodgersia is one of those plants that has bold leaves and bold blooms. The foliage has a bit of a bronze tinge to it and the leaves are quite thick, almost leathery to the touch. The plant enjoys sunshine, but moister soil. You’ll often see them growing at the edge of a pond or stream. Depending on the variety, flowers can either be white or pinky red. It also spreads out quite wide, so read the plant tag and be mindful of this when you’re planting.
Height: Up to six feet (1.8 metres) tall
Goatsbeard is one of those frothy perennials I love. They just add so much texture to a landscape. The cream-coloured flower spikes look a bit fuzzy from afar. The deer don’t eat this low-maintenance beauty. Plant goatsbeard in a shady spot. It can tolerate a bit of moisture in the soil.
Spotted Joe Pye weed
Height: Four to five feet (1.2 to 1.5 metres) tall
When I think of tall plants, Joe Pye weed is usually among the first that comes to mind. It attracts a number of beneficial insects, like butterflies, moths, and bees. Many of the varieties are cultivated forms a native plant that can be found throughout much of North America. Hardy down to USDA zone 4, you want to make sure that because of its exceptional stature, you choose the right spot for it, among your other plants.
False Indigo (Baptisia spp)
Height: Three to four feet (.9 to 1.2 metres) tall
A lot of the plants I’ve chosen have lovely long spires of blooms and this one is no exception. Modern hybrids come in a variety of colours. False or wild indigo are tough plants and pretty impervious to pests and diseases. They’re also drought tolerant. The foliage is sturdy and altogether the stems almost resemble a shrub, the way they stay nice and upright and together. They are hardy down to USDA zone 5.
Shopping for other interesting perennials? Check out these articles
- Perennials for small gardens
- Plant a rainbow: Pink, yellow, and purple perennials
- Deer-resistant perennials
- 10 of the longest-flowering perennials