How to Grow 10 Perennials for Continuous Summer Blooms

These 10 plants keep looking their best, even in the face of hot, dry conditions

Fine Gardening - Issue 182
Korean bellflower (Campanula takesimana 'Elizabeth', Zones 5–8)

If there’s one thing the most exciting gardens have in common, it’s that they always have something beautiful happening. And that “something” usually means something in flower. Bringing that idea home may seem challenging for gardeners, but happily, plant breeders know we want more—more beautiful foliage, more interest across every season, and most importantly, more and better bloom—and they have answered our calls. This is excellent news because, let’s face it, most gardeners today have less time to spend in the weeds (or looking for strong bloomers) than in years past. And everyone stands to benefit from bigger, continuous summer blooms with less effort. The following group of superstars starts flowering at the onset of summer and keeps going all season long, many even going right into fall. Use them as supporting players for those that shine more briefly, or switch it up and make them the centerpiece.

‘Orange Vanilla Popsicle’ red-hot poker is a deer-proof treasure

Orange Vanilla Popsicle red-hot poker
Photo: Doreen Wynja

Name: Kniphofia ‘Orange Vanilla Popsicle’
Zones: 6–9
Size: 12 to 24 inches tall and 12 to 18 inches wide
Conditions: Full sun; medium to dry, well-drained soil

Clusters of dusky orange spears arise from this plant’s grassy leaves all summer into fall, fading to cream as they open. A cheerful deer-resistant treat, ‘Orange Vanilla Popsicle’ is more demure in stature than the species. Red-hot poker appreciates sun and takes drought with aplomb. Well-drained soil is key in high-humidity regions, especially in the northern reaches of its growing range, where winter wet can lead to rot.


‘Thunder and Lightning’ knautia has cool blooms and foliage

Thunder and Lightning knautia

Name: Knautia macedonica ‘Thunder and Lightning’
Zones: 5–8
Size: 12 to 18 inches tall and wide
Conditions: Full sun; well-drained soil

It’s pronounced “naughty-uh,” but don’t let the name deter you. ‘Thunder and Lightning’ makes up for its smaller-than-the-species stature with its unbridled blooming enthusiasm. An extended stretch (from early summer to early fall) of mini-pincushions in vivid claret is supported by dreamy, creamy variegated foliage that makes the perfect foil throughout the growing season. Knautia needs cool nights to keep ticking into autumn, so it’s best suited to more northerly climes. Deadhead to promote even more late-season bloom. This cultivar tends to reseed less than the straight species.


‘Elizabeth’ Korean bellflower keeps the show going from spring to fall

Elizabeth Korean bellflower
Photo: Richard Bloom

Name: Campanula takesimana ‘Elizabeth’
Zones: 5–8
Size: 1 to 2 feet tall and wide
Conditions: Full sun to partial shade; medium to moist, well-drained soil

Korean bellflower works best as a multifaceted ground cover, and ‘Elizabeth’ is an especially attractive option that shines in shade. With tiers of flowers in a gradient of pinks reaching up to 2 feet, its glossy foliage prebloom is a bonus. This beauty readily flowers from late spring straight through summer. Bellflowers can be rowdy, and rather than plant ‘Elizabeth’ where it could crowd others, use it around trees and shrubs where it will be kept in check. Deer-resistant Korean bellflower most appreciates shade in the warmest reaches of its growing range.


‘Blue Cloud’ calamint is a floriferous understory plant

Blue Cloud calamint
Photo: Mark Bolton/

Name: Calamintha nepeta subsp. nepeta ‘Blue Cloud’
Zones: 5–8
Size: 12 to 18 inches tall and 12 to 24 inches wide
Conditions: Full sun to partial shade; medium to dry, well-drained soil

This plucky little ground cover starts its show with galaxies of lavender-blue flowers in midsummer that continue through fall. Though it comes with minty foliage and may seed a bit if it’s happy, calamint doesn’t run like other mints. It is a deer- and drought-resistant ground hugger that underplants well with bigger, bolder perennials. ‘Blue Cloud’ calamint may benefit from shearing to clean it up a bit in late summer.


‘Monarch’s Velvet’ potentilla is better behaved than its shrubby cousins

Monarch’s Velvet potentilla

Name: Potentilla thurberi ‘Monarch’s Velvet’
Zones: 5–9
Size: 1 to 2 feet tall and wide
Conditions: Full sun to partial shade; well-drained soil

‘Monarch’s Velvet’ potentilla features flowers in spring through fall of the clearest cherry red, each with a black eye. Unlike its woody relatives, you’ll find this species of potentilla growing near waterways and in cool, upland forests of the Southwest. Like those distant relatives, however, it’s relatively drought-resistant once it’s settled in and is rarely on the menu for deer. Afternoon shade is best in hot zones and sites.


‘Little Henry’ sweet coneflower is a compact version of a popular favorite

Little Henry sweet coneflower
Photo: Michelle Gervais

Name: Rudbeckia subtomentosa ‘Little Henry’
Zones: 4–9
Size: 3 to 4 feet tall and 2 to 3 feet wide
Conditions: Full sun to partial shade; moist, well-drained soil

Native to central North America, sweet coneflower is a plucky spin on the typical “Susan.” ‘Little Henry’ is a snug version of the tall cultivar ‘Henry Eilers’, but with its best attribute still: yellow daisies with tubular petals. Like other black-eyed Susans, it’s a must for gardeners in deer country in search of bright, late-season color. Unlike its cousins, though, it dislikes droughty soil.


‘Shoal Creek’ chaste tree takes drought in stride

Shoal Creek chaste tree

Name: Vitex agnus-castus ‘Shoal Creek’
Zones: 6–9
Size: 4 to 15 feet tall and 4 to 12 feet wide
Conditions: Full sun; medium to dry, well-drained soil

Lilac flowers and fragrant foliage belie chaste tree’s toughness, and ‘Shoal Creek’ is an especially tough customer. In warmer zones, it can be grown as a small tree, and it produces early and late flushes of lilac-blue blooms. North of Zone 7, cut it to the ground each winter, and watch it rebound to bloom during summer’s dog days. Drought- and deer-resistant chaste tree makes a great addition to the back of even the most sunbaked border.


‘Rosenkuppel’ oregano is more beautiful than the edible

Rosenkuppel oregano

Name: Origanum ‘Rosenkuppel’
Zones: 5–8
Size: 12 to 18 inches tall and wide
Conditions: Full sun; well-drained soil

An easy plant to weave through sunny gardens, this oregano outdoes its culinary cousins in beauty, but it comes with that signature fragrant foliage you’ll love and deer won’t. Starting in midsummer and going far into fall, ‘Rosenkuppel’ dots itself with bright pompons that begin with a magenta hue and open to pink. Like many Mediterranean ­natives, it’s a great choice for hot, dry sites. Sheer prebloom to keep it neat, or simply let it sprawl.


‘Autumn Minaret’ daylily sends up rockets of flowers

Autumn Minaret daylily
Photo: Michelle Gervais

Name: Hemerocallis ‘Autumn Minaret’
Zones: 3–10
Size: 4 to 6 feet tall and 2 to 3 feet wide
Conditions: Full sun to partial shade; fertile, well-drained soil

Daylilies always make reliable summer bloomers, and this cultivar sends up fragrant scapes of those voluptuous flowers from late summer well into fall. If that’s not enough, each one tops out up to a whopping 6 feet and sports yellow petals with an orange eye. This tall drink of water makes the perfect companion for meadow plants in full sun. Though daylilies will bloom in shade, more sun equals more flowers, and ‘Autumn Minaret’ is no exception.


Chinese indigo flies under the radar despite its amazing traits

Chinese indigo
Photo: Bill Johnson

Name: Indigofera amblyantha
Zones: 6–9
Size: 6 to 10 feet tall and wide
Conditions: Full sun to partial shade; well-drained soil

An underused gem from the legume family, Chinese indigo is a hearty shrub that promises upright candles of pink pea flowers by the thousands. This plant makes a great shrub for the cottage garden, with airy foliage and flowers that mesh well with neighboring friends. In cold climates, it may die to the ground in winter. Regardless, it’s best pruned back to the sturdiest stems before bud break in spring to remove dead wood and keep it in shape.

Keep the Season Going

Not every plant in your garden will be a strong summer bloomer. But here are some season-stretching tips to keep your garden looking good throughout the driest season.

Implement the Chelsea chop

Cut back bergamot (Monarda ‘Jacob Cline’) with shears in early June to encourage later flowering and a shorter, more compact habit. This is the so-called Chelsea chop.

In late spring, cut back early summer blooming plants by one-third to one-half. This encourages compactness and more blooms over a longer period.

Plant rebloomers

Look for early blooming plants that break for the heat and then bloom again later. Examples include dahlias (Dahlia spp. and cvs., Zones 8–11), ‘Walker’s Low’ catmint (Nepeta ‘Walker’s Low’, Zones 5–9), and ‘Rooguchi’ clematis (Clematis ‘Rooguchi’, Zones 4–9).

Feed the soil

Compost, compost, compost, and then mulch. More organic matter in soil gives plants better access to moisture and the nutrients they need to shine through the hot, dry summer.

Water smart

Install undermulch drip irrigation. This facilitates the kind of deep watering during the dog days that keeps plants fresh.

Andrew Keys is the author of Why Grow That When You Can Grow This? and Growing the Northeast Garden. He gardens outside of Boston.


View Comments


Log in or create an account to post a comment.

Related Articles

The Latest