How to Grow Biennial Flowers and 6 Garden Favorites

As a landscape designer and garden maker, I’m often asked by clients to replicate certain types of gardens. One common request is for a cottage-style garden filled with flowering plants that look wild and unkempt but are nonetheless carefully considered, placed and planted. One of the best ways to achieve this laissez-faire look is to use multiple layers of plants, including flowering shrubs and perennials, and then, to add depth and character, introduce the best of the best when it comes to unpredictability and seasonal surprise: biennial flowers.

Most gardeners eschew biennials because they aren’t permanent. Some think they were cheated when their foxgloves suddenly disappeared the year after they were planted, not realizing that they bought the plant in the second year of its two-year life span. 

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The first year of a biennial starts with a seed that grows through the season, making just roots and leaves. When winter comes, the shoots die back, but the roots survive. The plant re-emerges the following spring, just like a perennial, but during this second year it grows larger and ultimately forms flowers, fruits and finally seeds. The plant then dies, but if the seeds are allowed to scatter on the soil, they sprout anew come spring. 

If the cycle is broken at any point— the flower stalks removed from the plant before the seeds form, or the dispersed seeds raked or blown out of the beds—the biennial will disappear. 

Savvy gardeners understand this two-year cycle and find ways to include biennials, taking advantage of the random charm and variety they bring to any flower bed. Here are some of the best to try in your garden.

Related: Vegetable Crops That Do Not Need Pollinators

A European native, foxgloves (Digitalis purpurea; USDA Zones 4–8) have found a home in North American cottage gardens since the 1700s. It has often jumped the fence to spread into moist, organically rich woodland meadows. (Note: This species is listed as invasive in California and Oregon.) 

In its second growing season, showy two- to five-foot-tall spikes of pink, purple or white flowers peak in late spring above its one- to three-foot-wide clump of basal foliage. The tubular blossoms are especially attractive to hummingbirds yet unpalatable to deer, due to the flowers' toxicity. In garden settings, remove the first flower spikes after they finish to encourage a second bloom, which can be left standing to develop seed. The spikes of spent flowers look ugly as the seeds develop, though, so you may choose to leave just a few for self-seeding.

Foxgloves tolerate part sun, but they grow best in full sun situations with ample moisture. They will establish large colonies in optimum growing conditions, so plant them where generations of seedlings can self-sow. Avoid poorly drained soils where the first-year crowns will likely rot over the winter.

I grow my foxgloves along sunny woodland edges with spring bulbs like daffodils. Their emerging leaves hide the declining foliage of the bulbs. 

A tried-and-true staple of the late-summer cottage garden, hollyhocks (Alcea rosea; Zones 2–10) came to North America from Asia via European plant collectors. These somewhat wildly branching plants grow six to eight feet tall and two feet wide. Their dish-shaped flowers, ranging in color from white and yellow to pink, red and deep maroon, appear on rigid, unbranched spikes. 

Sow hollyhocks in late summer; they’ll sprout within two weeks, go dormant for the winter and return to provide a bounty of blooms the next year. Provide full sun and moist, well-drained soil for top performance and avoid locations with wet winter soil. Butterflies and hummingbirds frequent hollyhocks.

This is one of just a few plants that grow well near black walnut (Juglans nigra), being immune to the toxins released from the tree’s roots. Hollyhock foliage is susceptible to fungal infections and insect pests, but the flowers remain blemish-free and their stiff stems need no staking. I love hollyhock as a backdrop within a flowerbed or positioned in front of a tall wall. 

Sweet William (Dianthus barbatus; Zones 3–9) is the dianthus that doesn’t come back (as opposed to its cousin pinks). Another species from Asia, it has been a popular flower in European and North American gardens for many years. Highly fragrant flowers in solid or bicolor red, pink or white appear in dense, flat-topped clusters to five inches wide. 

Favored by hummingbirds and butterflies, the flowers will absolutely blanket each one- to two-foot plant if grown in full sun and organically rich, well-drained soil. In warmer regions, find a location with protection from the hot late-day sun. Deer avoid dianthus, but slugs do not, so check them for this pest if grown in some shade. 

Sweet William can sometimes behave as a short-lived perennial, and deadheading spent flowers may promote this tendency. However, it is really best treated as a biennial. I use this plant as a living mulch in newly planted ornamental beds. Plant them in the fall for blooms the following season, or purchase second-year plants in spring. I also include some of these in summer pots, matching them with annual flowers.  

Native to the rocky slopes of the French Alps, Canterbury bells (Campanula medium; Zones 3–9) grow one to three feet tall and wide in full to dappled sun and moist, well-drained, fertile soil. Upright clumps of stems produce long-lasting, sweetly scented, bell-shaped flowers of blue, pink and white from late spring into summer. They readily self-sow if just a few pods are left in place. Second-year plants can also be propagated by division in the early spring.

Appreciative of some extra attention, Canterbury bells prefer full to dappled sun and moist, well-drained, fertile soil. This species grows best in cooler climates; temperatures above 80 degrees (F) often make it wilt. The flowers require staking in windy spots. After the fall frost, mulch first-year plants with evergreen boughs or oak leaves in cold-winter climates, and monitor for slugs in spring. 

I grow my Canterbury bells close to paths and walkways where their striking blooms can be admired next to companions like delphinium and foxglove. Pollinators love them—and so do florists, who harvest them in bloom or after the seedpods have formed.  

Gloriosa daisy (Rudbeckia hirta; Zones 3–7) is a bigger, coarser cousin of familiar perennial Rudbeckia varieties like ‘Goldsturm’ and ‘American Gold Rush’. Growing three feet tall and two feet wide, this North America native bears three-inch-wide flowers with yellow to orange-yellow rays surrounding chocolate brown disks that inspire its other common name, black-eyed Susan. Flowering begins in summer and carries through to fall, making them excellent additions to any pollinator garden. Often found along roadsides in the wild, they thrive in full sun and tolerate deer, drought and difficult soils, except for poorly drained, wet ones.  

Sow gloriosa daisy seeds in any season. Some seedlings may flower in their first year if started early enough, but most won’t bloom until their second summer. Once they do, remove spent flowers to promote more buds. At the end of summer, let some flowers set seed and disperse. 

Gloriosa daisies have very few pest and disease problems, so I use them wherever I can in combination with native meadow plants, in masses along rustic stone walls paired with tall purple allium or scattered in a dry ditch that no one wants to mow. 

Named for its proclivity to grow along brick and stone walls, a certain southern Europe native is the epitome of a casually cultivated plant that lends both history and class to any garden. Wallflowers (Erysimum cheiri; Zones 7–9) are short—no more than two feet tall—and barely as wide. Bright clusters of fragrant yellow to orange-yellow and reddish-purple flowers sit atop vivid green leaves from middle to late spring. Better at attracting people than pollinators, these flowers are often picked and presented in small handheld bouquets, or nosegays. 

Wallflowers do best in dry, shallow, rocky soil, with full sun in cool climates and afternoon shade in warmer regions. If sown in early spring, they may provide flowers by fall, but it’s better to sow the seed in summer. The plants will get off to a good start before winter and then bloom in the spring and perpetuate by self-sowing. 

With no serious insect or disease problems, wallflowers should be more popular in the U.S. Though some have jumped the fence and naturalized in the Pacific Northwest, everywhere else they remain well-behaved. I plant them right where they belong: along sunny, south-facing walls in narrow strips of gritty soil, like you'd find between a home’s foundation and a driveway or sidewalk.  

Photos by Jack Coyier unless otherwise noted.

Daryl Beyers is a garden designer, writer, speaker and educator based in Shasta County, Calif. His latest book is The New Garden Designer’s Handbook (Timber Press, 2026).

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