Choosing to write an article about the ten best perennials created a bout of angst and overthinking about how could so many wonderful plants be whittled down to just ten. It also meant acknowledging that not only does subjectivity influence this list (although I try not to let it dominate), but also accepting that “best” is open to various interpretations. Therefore, I am choosing to write about ten great perennials that can be found blooming (or looking stunning) in our garden centers in June. The first five require sunny conditions, while the last five are happy in shadier locations.
Peony is a herbaceous perennial synonymous with cottage gardens. Offering lush foliage and bold single or double blooms four to five inches across, they herald the arrival of summer. Long-lived plants that dislike disturbance, they are best positioned either in the middle or back of flower borders, so that once their blooms are over their foliage can provide a foil to later blooming perennials. Whether it be the brilliant red of Buckeye Belle, the scented blush white of Shirley Temple, the traditional double raspberry red of Karl Rosenfeld or the perfumed double pink of Sarah Bernhardt, herbaceous peonies have something for every taste. Extending the qualities of these perennials are the Itoh peonies, initially bred by Dr. Toichi Itoh. These crosses between herbaceous and tree peonies offer not only bold and sturdy stems (no staking required with these!), but extend the flower colors to peach and yellow. Look for varieties such as Singing in the Rain and Bartzella to provide additional color choice.
Catmint (nepeta) is a hardworking perennial for sunny spots, and is tolerant of poor, dry soil once established. With is aromatic, blue-gray foliage, complimented by purple-blue flower spikes it is a magnet for bees. It offers plants of varying sizes starting with the petite and compact Little Trudy, extending through increasingly larger sizes of varieties such as Purrsian Blue, Cat’s Pajamas and Walker’s Low, all the way up to the aptly named Six Hills Giant. Once the first flush of flowers are over, shear it back and it will reward you with a second round of color. While most nepeta have purple-blue flowers it does come in other colors with nepeta alba offering white flowers, and nepeta Whispurr Pink having soft pink flowers. And if you fancy something a little different, look for nepeta Neptune. This variety grows 12” tall, has upright stems bearing green leaves, which end in spikes of large purple flowers. Just bear in mind that this variety is not as drought tolerant as others.
False Indigo (baptisia australis)
False Indigo (baptisia australis) is another plant tolerant of dry conditions, as it develops a long taproot to cope with a lack of surface moisture. Native to the mid-west prairies, it is equally at home in New England gardens, where it can provide early summer color and handsome, dense foliage on sturdy stems. Growing between 3 and 5 feet tall, it is best placed towards the back of borders, so as not to block out other plants. A member of the legume family, its pea-like flowers are popular with bumble bees, and will lead to seed pods resembling clusters of pea pods. Predominantly having flowers in shades of blue, hybrids have been developed that incorporate yellow and pink. Pink Lemonade actually combines both these colors, as its flowers start butter yellow and fade to a deep, dusky pink with age. However, if you are looking for a bright pop of color the aptly named American Goldfinch will make a bold statement of bright yellow flowers. And finally, if space is at a premium, baptisia Decadence Sparkling Sapphires tops out at 36 inches tall, and produces deep violet blue flowers.
Providing eye-catching color, salvia is another aromatic, drought tolerant perennial. Its dense clusters of long flower spikes are a visual contrast to the generally relaxed flower form of nepeta and it comes in complimentary colors ranging from white (Snow Hill) and pink (Rose Marvel), through pale blue (Perfect Profusion), violet blue (Blue Hill) and deep purple (Caradonna). With
long-lasting flowers loved by bees, their bloom time can be extended by removing spent flowers to encourage another flush of color.
Under the title of iris, I’m going to mention several types of iris that all bring color to the early summer garden. They share similar sword-shaped leaves, which contrast nicely with the rounder, clump-like foliage of many other perennials, and all have similar shaped flowers consisting of both upright and horizontal or downward facing petals. The smallest flowered of these are the Siberian irises, and Caesar’s Brother is a popular choice with deep indigo flowers.
In complete contrast, iris siberica Butter and Sugar has white and yellow flowers that are really eye-catching.
Iris ensata, Japanese iris, is best represented by iris ensata variegata – variegated iris, having green and white striped leaves. Therefore, once its purple flowers have finished, it is still a striking garden plant. This is an iris which prefers moist to wet conditions. If you cannot offer these conditions, choose iris pallida Variegata, which has green and yellow striped leaves and lavender colored flowers.
Finally, the iris that has the greatest color range is the bearded iris, iris germanica. Tolerant of dry conditions, it offers flowers ranging in color from white, through yellow, peach, red, and all shades of blue and purple, some of which are re-blooming.
Hosta are probably one of the plants most associated with shady conditions. While they have pretty white to lavender tubular flowers, which are attractive to hummingbirds, it is the mind-boggling array of leaf sizes and patterning that attracts the shade gardener. Variegation is a common feature, and fine examples of this are Patriot (white/green), June (gold/blue-green) and Stained Glass (gold/green). Blue/green foliage is also another common trait as exhibited by hosta sieboliana Elegans and hosta Halcyon. They also vary greatly in size from the diminutive Mouse Ears at 8 inches tall, to the dramatic giants that include Big Daddy, Sum and Substance and Empress Wu, which is an impressive 3-4 feet tall and 4-5 feet wide. And finally, if you are looking for something unusual, Praying Hands hosta with its folded, upright leaves is an eye-catching variety.
Coral Bells (heuchera)
Coral Bells (heuchera) are mostly cultivars developed from the native heuchera americana. Today’s hybrids offer brightly colored foliage, predominantly in shades of coral, orange, burgundy and purple with the occasional lime green. Flowers are not the main feature of these plants, with the exception of heuchera sanguinea which has conspicuous red flowers attractive to hummingbirds. Low growing, around 8-15 inches tall, they provide colorful ground cover in shady spots. Popular examples include Frosted Violet, Mega Caramel, a large caramel brown cultivar, Plum Pudding and Obsidian.
Tiarella (foam flower)
If flowers are what you are looking for, tiarella (foam flower) can offer the best of both worlds. This is another native plant, which requires shade and moist soil, making it ideal for the banks of streams. While it does not have the color range of heuchera foliage, cultivars generally have striking two-tone leaves, being green with red centers and veining. Similar in size and growth to heuchera, they also offer attractive bottlebrush flowers in white to pink. Look for the varieties Sugar and Spice or Elizabeth Oliver, or just the straight native, tiarella cordifolia. While this does not have two-tone leaf color, it makes good ground cover as it spreads by runners.
Astilbe is another plant that offers both attractive foliage and flowers. Even when not in bloom the fern-like leaves create visual interest, but they also have the bonus of colorful plumes of flowers ranging in color from white, through pink, peach and lavender to red and magenta.
The Visions range offers a variety of colors from white to pink to red and purple; height when blooming is around 30 inches. Bridal Veil is a beautiful white variety while Fanal, although a little shorter, packs a punch with deep red flowers. Purple Candles is an impressive variety, growing to 3.5 feet tall and sporting colorful flowers of violet-red. Peach blossom is the most unusual flower color among astilbe and as its name suggests, is a delicate peach color.
Ajuga or Bugleweed
Ajuga or bugleweed, is a wonderful ground cover for shady conditions, generally growing only a few inches tall. Primarily grown for its striking foliage, it does have attractive deep blue flowers in early summer. Small plants can quickly spread to form broad carpets of color, so give it plenty of room. An easy care plant, it requires little maintenance – dead-heading is a matter of personal preference, and the occasional trimming of stems if they are out of bounds is all that is required. Popular varieties include Burgundy Glow, with tri-colored leaves of white, pink and burgundy; Black Scallop which has deep burgundy, almost black leaves with pronounced scalloped edges, and Bronze Beauty whose green leaves are attractively tinted bronze.
These are just ten early summer perennials – to write about all the wonderful garden plants there are would warrant a book, not an article!