My Favorite Summer Flowering Perennials
Summer is in full force and man, can we feel it. This summer especially, as all the griping about rain the past couple years has finally caught up with us!
Summer is a conundrum for me because even though I have a high disdain for heat, it’s nevertheless my favorite season – it’s when most flowers bloom! Even on a miserable day, seeing them in the wild or garden makes me happy.
While there are wonderful shrubs (and annuals of course) that bloom in summer, the focus of this post is on perennials. I think perennials ought to be the workhorses in the garden. They deliver so much color, texture, and form, as well as food for pollinators, while taking up less room than most shrubs and trees. While there are many terrific summer flowering perennials, I decided to identify my favorites that I think you should incorporate into your outdoor spaces! Well, these are summ-er of them anyway!
Delphinium (Delphinium sp. and hybrids)
If I had to pick one plant in our entire garden center to label “aristocrat”, it would be the delphinium. This perennial comes in pinks, purples, whites, and true blues. In fact, I don’t think any other garden plant comes in such a variety of true blues as the delphinium. The flower stems tower above the plant in early summer, and larger varieties will certainly attract the neighborhood’s gaze.
Delphiniums appreciate a sunny but cooler place with well-drained soil. Avoid planting near any cement or landscape rock as they will reflect heat onto the plant. Also avoid smothering this plant with mulch in the winter to reduce the risk of rot. Plant delphiniums in groupings for an impactf; as with many vertical perennials, one standalone plant looks wimpy. Plants you see in garden magazines are almost always of groupings!
We bring in several series, including delphiniums from the New MilleniumTM and Magic Fountain series, which tend to be smaller but have better tolerance for heat and humidity. We also bring in plants from the Pacific Giant series, which are larger in stature. If you’re interested in learning more, I recommend gardenia.net, which is a great informative site on perennials, including delphiniums!
Garden Phlox (Phlox paniculata)
What’s an east coast garden without garden phlox? This native blooms beginning in mid-summer and offers a lengthy bloom time, often spanning July to September. The panicles of blooms come in pinks, corals, purples, and white. One of my favorites is David Phlox (Phlox paniculata ‘David’) which is a beautiful crisp white that stands a couple feet high or so.
Phlox is known for being prone to powdery mildew, which although unsightly, is usually not fatal. The best way to beat this, however, is to plant your phlox in full sun and water the root zone – avoid wetting the leaves when possible. As I say, all plants have their strengths and their weaknesses. The key isn’t to avoid plants with any weakness – it’s to learn how succor them! That said, some cultivars are more resistant than others and David Phlox is pretty good!
At my house, I have Jeanna phlox (Phlox paniculata ‘Jeanna’) throughout the front garden. The individual blooms are smaller than many other cultivated varieties, but my, do the butterflies love all those little blooms! I also enjoy the coral color of Glamour Girl (P. paniculata ‘Glamour Girl’).
Black Eyed Susan (Rudbeckia sp. and hybrids)
I could do a whole blog post on the Black-Eyed Susan. Maybe stay tuned!
Black Eyed Susan is another perennial that every Pennsylvania landscape should incorporate. Popular around the world, this plant is native to our own backyard. Perennial Black-Eyed Susan only comes in yellow, but if you could only come in one color, wouldn’t a cheery yellow be your choice?
There are several species native to our area that are available in commerce, and many hybrids and cultivars. ‘Goldstrum’ is among our top selling cultivars (Rudbeckia fulgida var. sullivantii ‘Goldstrum’), but I know right now, we probably have a dozen or so different ones in stock! My favorite is a cultivar of the Tall Coneflower (R. laciniata) called Herbstonne which gets around 4 to 5 feet tall. Tiny ones are also available, including Little Gold Star (R. fulgida ‘Little Gold Star’) which is around a foot tall. There are so many more!
Black Eyed Susan blooms from mid-summer till fall, with variance between the species and varieties, offering a long bloom time for both human and pollinator delight! Mine have been blooming for a couple months already and are showing no signs of fatigue!
Bee Balm and Wild Bergamot (Monarda didyma, M. fistulosa, sp. and hybrids.)
Bee balm and wild bergamot are two native species of Monarda although both – and their hybrids – are often referred to as just Bee Balm. True to the name, bees love this plant! I wish more gardens and landscapes used this plant as it’s an important food source for bees and many other pollinators – plus they are beautiful! I really like Proven Winners Pardon series, such as Pardon My Cerise and Pardon my Lavender.
Monarda didyma cultivars are tolerant of average to wetter soils while Monarda fistulosa cultivars are tolerant of average to drier soils. Most cultivars are hybrids but the Pardon series is of the former, meaning it can take wetter soil. They both appreciate full sun but will still bloom in part-sun.
Bee balm also blooms in what is often the hottest part of summer, which is a welcome sight. And, as the plant has a sage-like fragrance, the deer leave them alone. Perhaps a modern day balm of Gilead would be a (bee) balm of Plum!
Coneflower (Echinacea sp. and hybrids)
Coneflowers are one of our top selling perennials. What’s a classy landscape without coneflowers in summer? The pollinators love them and we do too! There are 10 species and a multitude of cultivars. They come in short and tall sizes, single and double blooms, and even less common colors such as true reds, oranges, and greens. One of my favorites is White Swan (Echinacea purpurea ‘White Swan’) which is a white flowering form that averages between 2 and 3 feet tall.
The blooms fade in late summer for most cultivars but I resist the urge to chop them off. Here at the nursery, we let them go to seed. The American gold finches love them and the flower stems provide overwintering space for native bees and other beneficials.
Goatsbeard (Aruncus dioecious)
This list would be incomplete without adding a shade perennial! An astilbe look alike, this native perennial hosts hundreds of tiny white blooms on tall stems. This adaptable plant can take part-sun to part-shade and grows in average to damp soil. This is a larger perennial, averaging 3 to 4 feet tall, so this is a great substitute for a shade shrub.
Proven Winners’ has a cultivar called Chantilly Lace (Aruncus ‘Chantilly Lace’), which has a more floriferous habit. A dwarf form called ‘Misty Lace’ (Aruncus ‘Misty Lace’) is also available. I have Goatsbeard in pots at home, and they’ll go in as I can get my part-sun bed ready for them!
Joe Pye Weed (Eutrochium sp. and hybrids)
This flowering native perennial is underutilized in the landscape! Contrary to the name, this is no weed, but a native, hardy, deer resistant, and low maintenance perennial. It flowers for 2-3 months, which is a long time, and the pollinators love it.
There are several species and a handful of cultivars. A lot of Joe Pyes get tall, but there are dwarf forms such as Little Joe (Eutrochium dubium ‘Little Joe’) and Baby Joe’ (E. dubium ‘Baby Joe’). We also carry a variegated form called Pink Frost (E. fortunei ‘Pink Frost’) that’s so easy to care for that, shall we say, it’s a very “chill” plant!
This plant is also heat, salt, and wet tolerant so I planted ‘Baby Joe’ near my mailbox this year where it won’t mind these conditions. Many plants are prone to rotting if it gets to wet during the winter. Not so with Joe-Pye!
Others Honorable Mentions
Salvia (Salvia sp.)
Another easy, deer-resistant, and long-blooming perennial, Salvia come in purples, pinks, whites, and bicolors. I have several Snow Hill Salvia (Salvia ‘Snow Hill) at home; the pollinators love them and the deer don’t bother them! I also like Proven Winners’ cultivar ‘Azure Snow’ from their Color Spires series® which is bicolor of pansy-purple and white! Their cultivar ‘Violet Profusion’ is also great!
Meadow Rue (Thalictrum sp.)
A delicate looking but tough plant, this lesser-known perennial is a great addition to the landscape. The pollinators enjoy this plant and like delphiniums, groupings are quite striking. We often carry the NimbusTM series. Full sun is fine but a little light shade during the heat of the afternoon is appreciated.
Yarrow (Achillea sp.)
Another great addition to the landscape, this low, long blooming perennial is easy to care for and a boon for butterflies. The ferny foliage is beautiful and after the flowers are complete, you can leave the dried flowers in the plant for texture and interest through the fall. As yarrow is drought tolerant, this has been a good year for this plant to shine! Avoid over watering it though; too much is yarrow’s Achilleas-heal!
Customers often ask if summer is an okay time to plant. I say yes! Plants are always happier in the ground than in pots. We can maintain happy plants here all summer long so they’ll certainly appreciate going to a good home at this time. Planting in summer just means you have to keep an eye on the watering, more so than you would in spring or fall. I’m still planting in my garden right now! Additionally, summer blooming perennials are in bloom at the nursery so now is a good time to get an idea of what they look like. Plus summer’s selection is always the best!
Remember every year we bring in perennials from our growers through September. We try to carry a good selection throughout the year, rather than just a couple months like some nurseries. So, come on in and go liberal on planting summer flowering perennials!
But with all that said, leave some room and stay tuned for my upcoming blog post on fall flowering perennials! Happy plantings!
Photos provided by Plumline Nursery employee Aaron Grabiak with Aaron Grabiak Garden Photography & Landscape Design, Perennial Farm, and Proven Winners.