Summer Flowering Perennials
As Spring color dissolves into the heat of summer, new and varied plants emerge. Hearty, and bold, summer flowering perennials are the main attraction, providing color and interest all season long. This selection of plants covers those that bloom from June to September, some of which carry into fall. We’ve provided images and descriptions of some of our most successful and dependable summertime garden staples.
Yarrow- Achillea
Zone: 3-8
Light Requirements: Full Sun
Soil Preference: Medium moisture well drained soils
Pests/disease: Botrytis, powdery mildew and rust
Attributes: Yarrows are summer flowering staples of the perennial border. There are many cultivars/varieties, but each has fern like, somewhat fragrant foliage and long lasting, vivid, umbel shaped blooms. Many can withstand drought, but they generally prefer moist soil. Deadheading results in repeat bloom.
Our Experience: Yarrow graces many full sun garden areas on Great Hill. It performs best, for us, in lean soils with good drainage. Tired plants require division every 3-4 years. Grows 10-36” depending on cultivar.
Ladys Mantle- Alchemilla
Zone: 2-7 depending on cultivar
Light Requirements: Sun to Part Shade
Soil Preference: Medium moisture well drained soils
Pests/disease: None Serious
Attributes: Clump forming perennial with scallop edged, toothed, hairy, light green leaves and tiny star shaped chartreuse colored flowers emerging early in the summer.
Our Experience: Any border, walkway, path or ponds edge is enhanced by the presence of alchemilla. The foliage is distinct and colorful and often collects dew drops enhancing the aesthetic of any view. While the flowers are small, their color against the blue/green foliage causes them to pop more than the average small flower might during the early summer.
Calamint- Calamintha
Zone: 5-9
Light Requirements: Full Sun
Soil Preference: Average medium to dry well drained soils
Pests/disease: None serious
Attributes: A mounding perennial with fragrant, white, cloud like flowers and fine textured, minty foliage. Great source of nectar for pollinators. Grows to 24.”
Our Experience: Calamint is long blooming and very low maintenance. It brings a lot of fragrance, during the summer months, to a number of our border gardens. Shear it for shape and sporadic re-bloom after first flower. Can be utilized along pathways as a low growing hedge.
Turtlehead- Chelone
Zone: 3-8
Light Requirements: Part Shade
Soil Preference: Moist to wet rich soils
Pests/disease: None serious
Attributes: A summer flowering woodland naturalizer that does well in wet soils and is known to attract pollinators. Blooms are hooded, snap dragon like, and white or pink depending on cultivar. Chelone is clump forming and grows 24-48.”
Our Experience: This woodland perennial graces our shade garden and is stunning when in bloom- unfortunately, many of our regular garden “guests” agree. We do have an issue with deer browsing this plant.
Tickseed- Coreopsis
Zone: 4-9
Light Requirements: Sun to Part Shade
Soil Preference: Dry to medium well drained soils
Pests/disease: Crown Rot or mildew in poorly drained soils. Rabbit browsing.
Attributes: A large group of plants with lots of variety, each having daisy like flowers and blooming yellow, red, pink or white, with long bloom times. All grow in clumps and benefit from shearing after bloom to keep compact and encourage re-bloom.
Our Experience: This yellow flowering standard graces many sunny garden beds on the hill. Its fast growing and long blooming with delicate airy foliage. We have had an issue with rabbits browsing on flower buds in our English garden.
Larkspur- Delphinium x elatum ‘Magic Fountains’
Zone: 3-7
Light Requirements: Full sun
Soil Preference: Average, moist, well drained soil
Pests and Disease: Leaf spot, powdery mildew and mites to name a few.
Attributes: The Magic Fountains series are a dwarf delphinium bred for stake free blooms and heat tolerance with foliage that remains green during the growing season. These delphiniums grow 2 to 3’, bloom in pink, white or blue and can re-bloom later in the season when properly cared for and deadheaded.
Our Experience: We’ve trialed this delphinium on several occasions in a number of garden areas with limited success. While this cultivar is a great improvement to older garden delphiniums, we still cant seem to keep deer and rabbit from eating them to death where planted. In areas we’re able to fence, such as our cutting garden, we grow them as annuals for cut flowers.
Queen of the Prairie- Filipendula rubra
Zone: 3-8
Light Requirements: Full sun to part shade
Soil Preference: Average, medium to wet well drained soils
Pests and Disease: No serious pest or disease problems
Attributes: Filipendula is a summer flowering perennial native to the Midwest where it grows in swamps and wet meadows. While there are shorter cultivars, the species can reach 6 to 8’ and features large, showy, light pink to red panicle flowers with a slight fragrance. Leaves are also fragrant, bright green, pinnate, large and deeply cut.
Our Experience: We feature a dwarf form of filipendula in our fragrance garden on great hill. While this species is large, it usually does not require staking unless placed in an overly shady spot (which ours is). We’ve experimented with deadheading for prolonged bloom, but found that this practice has little effect on the appearance of new blooms or bloom duration. Plant foliage will scorch if the soil isn’t kept adequately moist. Filipendula is lovely in beds and borders adding height and texture to the garden.
Blanket flower- Gaillardia aestivalis
Zone: 5-9
Light Requirements: Full Sun
Soil Preference: Dry to Medium
Pests and Disease: No serious insect or disease threat. Can be susceptible to powdery mildew and rot if soil is not well drained, fungal leaf spot and aster yellows.
Attributes: Prefers to be planted in soils that are regularly watered but drain well. Grows to approximately 18” tall, and blooms from late spring to fall. Flowers have bright yellow petals with red bases, surrounding a brownish purple center. Once the petals drop the central disk still remains attractive. Frequented by birds and butterflies. Leaves are lance-shaped dark green- gray green depending on the cultivar. If plant stops flowering, consider cutting back to 6” mid summer to allow for a strong fall rebloom, better form, and new growth from the base for better overwintering.
Our Experience: Do well in very hot dry conditions. Consistent performer with long lasting blooms. Suitable for cut or dry flowers.
Prairie Smoke- Geum triflorum
Zone: 3-8
Light Requirements: Full sun
Soil Preference: Average, well-drained soil
Pests and Disease: No serious pest or disease problems. Can rot if placed in poorly draining soil.
Attributes: A clump forming perennial growing 12-18” featuring reddish-pink (sometimes purple) bowl shaped flowers followed by seed heads bearing long, thin, silvery pink tails, resembling plumes of smoke. Foliage is blue-green, fern link and can be evergreen in warmer locations. A good naturalizer where happy.
Our Experience: This geum makes a beautiful ground cover in mixed beds and borders and we use it as such throughout the estate for multi seasonal interest. The contrast between foliage and flower color followed by long lived, flowing seed heads makes for an eye catching display.
Daylily- Hemerocalis
Zone: 3-9
Light Requirements: Full sun to part shade
Soil Preference: Dry to medium well drained soils
Pests/disease: None Serious
Attributes: Low maintenance, easy to grow and very adaptable summer blooming perennial coming in a range of sizes and bloom colors. Beautiful and long-lasting flowers make this perennial a border, edging or massing garden staple.
Our Experience: Daylilies, while beautiful, and tolerant of neglect, can be a maintenance nightmare if needing to be kept looking clean and tidy. As the name denotes, each bloom lasts about a day. This being the case, we plant re-bloomers (or ever bloomers) whenever possible on the hill. Along with deadheading, regular cleaning up of foliage (either pulling, raking or pruning to the ground) is normally done as well to keep up tidy appearances.
Hardy Hibiscus- Hibiscus
Zone: 5-9
Light Requirements: Full sun
Soil Preference: Medium to wet organically rich soil, will perform in average garden soils as well as long as they are not allowed to dry out.
Pests and Disease: Leaf spots, blight, canker, and rust can occur. Japanese beetles, whiteflies, sawflies, and aphids can occasionally be an issue if left unchecked.
Attributes: very showy in late summer with dinner plate sized flowers resembling a hollyhock. Colors range from white with magenta ring in the center to crimson. Plants have a woody base and grow from 3-4’ in height.
Our Experience: Very ornamental perennial. Ours grow much larger than 3-4’ easily reaching 6’ with profuse large, brightly colored blooms. We have had no issue with disease or insects. Our hibiscus are watered regularly, but are not planted in a particularly wet area yet still perform extremely well.
Plantain Lily- Hosta
Zone: 3-8
Light Requirements: Part Shade – Full shade
Soil Preference: organically rich, evenly moist, well drained soil
Pests and Disease: Slugs and snails can be an issue, deer will also consume hosta. If Viruses such as tobacco rattle virus, tomato ring spot, or Hosta Virus X (HVX) are detected, the plants should be removed from the garden and destroyed.
Attributes: Very low maintenance attractive perennial. Mostly grown for the rounded heart shaped leaves, racemes of white, sometimes fragrant flowers contribute to the appeal of hostas. Available in many different sizes and colors, they make an ideal addition to any shady area.
Our Experience:Very versatile plant, divide approximately every two years. We have had success dividing and transplanting at various times in the season, though spring or fall is best. We have some hosta in sunnier spots. They do fine, but their foliage depreciates earlier in the season than plants situated in more ideal locations. We’ve not run into issues with pests or disease.
Lavender- Lavandula
Zone: 5-8
Light Requirements: Full sun
Soil Preference: Dry to medium well drained soils
Pests/disease: Leaf spot and root rot in soils not well drained
Attributes: A large group of flowering herbs that favor lean soils and well drained conditions. Many cultivars have grey-green foliage, showy purple flowers and are often used as a low hedge or edging plant. Plants benefit from pruning in the spring for shape and to encourage robust growth.
Our Experience: Lavender is best utilized in poor soils and full sun conditions. We use lavender for summer color and fragrance in our Monet garden, only running into issue when its situated in a bed with other plants that require more water. Performs better when placed in a sheltered winter location. Grows 2-4’ depending on cultivar/variety.
Gayfeather- Liatris spicata
Zone: 3-8
Light Requirements: Full sun
Soil Preference: Medium well-drained soil
Pests and Disease: No serious pest or disease problems
Attributes: Liatris is a tall, upright, clump forming perennial growing 2 to 4’. In mid to late summer, liatris features spikes of purple blooming flower stalks up to 12” in height. Foliage is bright green, narrow and grass like. Used widely in perennial and cut flower gardens.
Our Experience: We grow liatris in a large perennial garden on the estate. While the flowers are highly ornamental, our plants don’t perform as well as other summer bloomers more tolerant of the dry conditions on great hill.
Plume Poppy- Macleaya microcarpa
Zone: 4-9
Light Requirements: Full sun to Part Shade
Soil Preference: Average, well-drained soil
Pests and Disease: No serious pest or disease problems
Attributes: Plume poppy is a vigorous, upright, spreading perennial growing 6 to 8 feet with rounded, lobed grey-green leaves and large panicles of pink flowers. Flowers are long lasting and often used for cuts.
Our Experience: We’ve utilized plume poppy in a large bed adjacent to a parking area on Great hill for its drive by appeal of height, long flowering period and ornamental leaf color. When used in the right setting, this perennial is a show stopper- but beware! Macleaya is an aggressive spreader and needs its own space. When interplanted in the garden it will quickly spread and take over by way of a thick and quickly spreading root system as well as through prolific seed production.
Shasta Daisy- Leucanthemum
Zone: 5-9
Light Requirements: Full Sun
Soil Preference: Dry to medium well drained soils
Pests/disease: Wilt, leaf spot and aphids, rarely
Attributes: An easy to care for summer perennial with a mounding or spreading habit and classic white or yellow daisy flowers. Requires good drainage and division every 2-3 years.
Our Experience: We’ve found that shastas will regularly rebloom if deadheaded, though not as vigorously. Basil foliage holds up well in the garden throughout the fall. Taller forms require staking, to avoid this, pinch plants back in late May. Great cut flower.
Leopard Plant– Ligularia
Zone: 4-8
Light Requirements: Part Shade
Soil Preference: Medium to wet well drained soils
Pests/disease: None Serious
Attributes: Summer blooming shade perennial that requires constant moisture. Ligularia has daisy like or spiked (depending on cultivar) yellow flowers atop tall stalks later in the summer but is usually planted for its big and bold leaf color and or texture which give a tropical feel to the garden.
Our Experience: Ligularia adds distinct color and texture to our shade garden. As Its location is sufficiently wet and shady most seasons, we’ve not had any major problems with foliage dry out and or die back. Grows to 20-36” depending on cultivar/variety.
Bee Balm- Monarda
Zone: 4-9
Light Requirements: Sun to part shade
Soil Preference: Dry to medium well drained soils
Pests/disease: Powdery mildew and rust
Attributes: A summer flowering perennial that’s both a showy ornamental as well as an essential nectar provider. Bee balms grow up to 4’ in height and flower in a range of colors from red, pink, and lilac to white. While powdery mildew has been a consistent problem for this perennial in the past, newer cultivars are bred for high resistance to fungal pathogens.
Our Experience: For a gardener, there’s nothing quite like witnessing the range of nectar seekers brought into your garden via blooming bee balm. It’s very tolerant of a range of soils as well as a wide range of animal browsing (deer, rabbit and groundhog on the hill). To keep compact prune in half in early May (if the critters don’t do this for you). If foliage starts to decline after blooming, you can cut it to basil growth, but it will not regenerate any taller than 6-8.”
Catmint- Nepeta
Zone: 3-9 depending on cultivar
Light Requirements: Sun to partial Shade
Soil Preference: Dry to medium well drained soils
Pests/disease: None Serious
Attributes: Nepeta comes in many varieties ranging in height, bloom time and foliage size/color. Every nepeta, though, is a long blooming, clump forming herb that’s very drought tolerant, with lavender-blue colored flower spikes.
Our Experience: Nepeta is a gardener’s classic summer herb. Prune back by two thirds after flowering to keep compact and encourage rebloom. Range of cultivars in height ensures you can place nepeta anywhere in the garden.
Ornamental Oregano- Origanum laevigatum ‘Rosenkuppel’
Zone: 5-8
Light Requirements: Full Sun
Soil Preference: Dry to medium moisture well drained soils
Pests/disease: Fungal diseases in wet soils, aphids and spider mites
Attributes: Rosenkuppel oregano is a hardy, clumping perennial that grows to 15”, has dark green leaves, and tiny whorled violet-red flowers from summer to early fall. Used as a massing plant, in herb gardens, rock gardens and containers.
Our Experience: Rosenkuppel is utilized as a repeating, spreading, massing plant along the border of our English garden. It has an incredible scent and long lasting flowers while being incredibly low maintenance and both deer and rabbit proof. To keep this oregano compact, and to promote rebloom, we prune it by half early to midsummer.
Beardtongue- Penstemon digitalis ‘Husker Red’
Zone: 3-8
Light Requirements: Full Sun
Soil Preference: Dry to medium moisture well drained soils
Pests/disease: Root rot and leaf spot when in wet soils
Attributes: Husker red penstemon is a clump forming perennial growing 2 to 3’ tall with panicles of white, two lipped tubular flowers that sit on erect stems over deep maroon turning dark green lance shaped leaves. Often used in sunny areas and border gardens.
Our Experience: We use this penstemon variety as an accent perennial planted in a bed that follows a sloping stairway. This cultivar of penstemon works wonderfully as an accent with its two toned leaves against its bright white flowers creating a highly ornamental affect where planted.
Rodgers Flower – Rodgersia
Zone: 4-9
Light Requirements: Part Shade to Shade
Soil Preference: Medium to wet well drained soils
Pests/disease: None Serious
Attributes: Bold, clump forming woodland perennial native to Japan with astilbe like creamy white flowers and large, coarsely toothed, palmate green to bronze leaves. This perennial covers some ground! The leaves are large and change color throughout the season often emerging red/bronze maturing to green and returning to copper/red in the fall.
Our Experience: We utilize rodgersia in our shade garden as a large and ornamental summer feature (as fewer perennials bloom in the shade during the hot summer months than in the gardens with full sun). Be sure to plant in consistently moist soil to get the most height/color variation out of the large foliage.
Salvia- Salvia azurea
Zone: 5-9
Light Requirements: Full sun
Soil Preference: Dry to medium
Pests and Disease: Occasionally white flies and scale can be an issue, also susceptible to rust and leaf spot. Generally no real disease or insect threat
Attributes: Clump forming plant with spikes of two-lipped bright blue flowers mid summer- fall. Whole plant is 3-5’ with that stems that carry linear lanceolate to obovate silvery green leaves approximately 3-4” in length.
Our Experience: Extremely low maintenance plant. Prefers to be very dry. If deadheaded after initial bloom, will re-bloom throughout the summer and into fall. Great cut flower. We have grown a number of different cultivars in a variety of sizes. Larger specimens must be staked. No issues with pests, rodents, or disease.
Lambs Ears – Stachys
Zone: 4-8
Light Requirements: Sun to Part Shade
Soil Preference: Dry to medium well drained soils
Pests/disease: Tends to rot and or develop leaf diseases in high heat/humidity.
Attributes: Low growing, mat forming, edging perennial (in most forms). As the name denotes, this plant is often utilized for its thick, velvety blue/silver/green foliage resembling a lambs ear. Some cultivars flower pink on long stems, but many gardeners chose to deadhead these blooms as their maturity often results in foliar decline and take away from the ground cover effect.
Our Experience: While we do have stachys groundcover on the front border of the English garden, we find it, for a ground cover, pretty labor intensive. Our soil, while relatively well draining, doesn’t appear to be as dry as this plant prefers. We dig up and transplant clumps to fill in where large areas rot and die back regularly during the growing season. One stachys that we truly treasure in the English garden though, is stachys monieri ‘hummelo.’ This is a large mounding cultivar that resembles agastache or salvia. It flowers purple for a long period of time mid-summer, does not have rotting issues and requires little to no maintenance.
Stokes Aster – Stokesia
Zone: 5-9
Light Requirements: Full Sun to Part Shade
Soil Preference: Average medium moisture well drained soils
Pests/disease: None serious
Attributes: Stokesia is a summer blooming perennial growing 1-2’ with daisy like violet/blue or white flowers with notched rays and a pincushion center.
Our Experience: Stokesia’s fluffy, fringed, often lavender blue flower makes it stand out beyond other perennials of similar height during the summer. Its an easy plant, requiring little maintenance other than deadheading in order to prolong bloom.
Meadow- rue – Thalictrum
Zone: 5-9
Light Requirements: Full Sun to Part Shade
Soil Preference: Average, medium moisture well drained soils
Pests/disease: None serious
Attributes: A tall meadow flower growing to 6′ depending on cultivar, with fine textured, blueish green foliage and purple/pink, white or yellow fluffy flowers in dense panicles atop wiry stems.
Our Experience: Thalictrum has seeded itself into many areas of Great Hill and has been welcome in the majority of cases. While the flower is an impressive component, the foliage, once identified, is easily recognizable and impactful, while remaining light and airy. If the foliage declines following flowering, cut to basil growth for some regeneration.
False Lupine- Thermopsis
Zone: 3-9
Light Requirements: Sun
Soil Preference: Dry to medium well drained soils
Pests/disease: None Serious
Attributes: A summer flowering perennial with pea like foliage and tall flower stalks resembling lupine that bloom a canary yellow color. Grows 36-60.”
Our Experience: Thermopsis is a great summer flowering addition to any perennial border garden. Its seed heads have long shaggy hairs adding interesting texture to the garden. Plants sometimes decline by midsummer. Cut them to the ground if this occurs and foliage often regenerates.
Speedwell- Veronica austriaca
Zone: 4-8
Light Requirements: Full sun to part shade
Soil Preference: Average, well-drained, medium soil.
Pests and Disease: No serious pest or disease problems
Attributes: Blue flowers grow in upright axillary racemes over foliage with a sprawling mounding habit. Leaves are medium green, oblong, with toothed edges. Flowers bloom in early summer and can be trimmed back after flowering to encourage a less full, late summer second bloom.
Our Experience: We take full advantage of the sprawling/mounding habit in our design. Makes wonderful mono planting providing lavender-blue blooms in early summer. It can get unruly looking if not trimmed back to the secondary bud. Haven’t had any issues with pests, rodents, or disease.
Culvers Root- Veronicastrum virginicum
Zone: 3-8
Light Requirements: Full Sun
Soil Preference: Medium to wet well drained soils
Pests/disease: None serious
Attributes: Veronicastrum is a large, erect perennial growing 3 to 7’ tall with lance shaped whorled leaves and 9” long spiked flower racemes. Racemes are made up of tiny tubular flowers coming in white, pink and pale blue and bloom from late spring through late summer. Each raceme contains several smaller branching spikes giving the flowers a candelabra effect. Veronicastrum is used in meadows, cottage gardens, borders and native wild gardens.
Our Experience: We use veronicastrum in our English border garden for tall mid summer color. As the soil in this garden is on the dry side, plants tend to fade quickly post flowering and are usually cut to the ground by summers end.