Everywhere I look – in private gardens, at country clubs, on garden tours, in public gardens and at the garden center – flowering perennials are astounding this year. Most of them benefited from great bouts of heat and generous rainfall just when they needed it. They are tall, full of buds or flowers, and most have not been attacked or damaged (although trouble for some may be fomenting just around the corner). If you don’t necessarily know every kind of perennial intimately, let me tell you about some of the beauties you may be seeing during their peaks of performance.
Some flowering perennials have finished their first blooming period. It could be their last for the season, as some perennials don’t flower after spring no matter what you do. If you don’t cut perennials back after they flower and you let them form seeds, they basically get the hormonal signal: No more flowers this year; closed for the season. So inspect your early bloomers, and if the first big flush is waning, cut the plants to half their size. Then watch: Many will rebloom in just a few weeks.
Penstemon: The popular dark-leaved ones with tubular white flowers are probably ‘Husker Red’ or ‘Dark Towers,’ and I declare them essential in a perennial border. Plant them in groups of three, so the clumps of maroon foliage provide waves of contrast with greener neighbors, both before and after flowering. Cut them back for more flowers in August. Hummingbirds love all Penstemons. This year the stalks are really tall – up to 3 feet – and have looked great for weeks.
Aruncus dioicus (Goatsbeard) and Polygonatum (Solomon’s Seal): These are shade garden staples, and I mention them together as two solid citizens that never let you down. Variegated Solomon’s Seal was the Perennial Plant of the Year for 2013 – elegant among hostas and in woodlands. Goatsbeard can be a shrub substitute at 4-by-4 feet, with strong white plumes that last for a few weeks. Cut it back by about one-third when it looks shabby.
Dianthus, also called Pinks, Carnations or Sweet William (the biennial form): This genus includes 300 species with thousands of cultivars, so don’t expect to match the one you bought three years ago. Do plant them in great drifts along a bank or front of a border, always in sun, always with decent drainage. I have seen great sweeps of them recently in some drive-by gardens but also heard that some died when they heaved out of the soil last winter or got waterlogged.
Campanula glomerata (Clustered Bellflower): Although many kinds of Bellflowers are useful, C. Glomerata has several great cultivars with large purple clusters. They line my garden path and always receive compliments. Cutting back induces more flowers, and it’s OK to rip some out when they get too exuberant.
Irises: While lots of water could be tough on bearded irises in poorly drained soil, some irises are water gluttons. Plantswoman Kathy Guest Shadrack reports: “The Siberians, ensata and pseudata have been outstanding (the beardless varieties.) They are blooming heavy and happy as can be. I think they appreciate this very wet spring.”
Flowering through July
Every season has its own timing, and you cannot guarantee that roses or foxgloves or lilies will be flowering during any specific week. (Just ask someone preparing for a garden walk or tour coming to the garden and you’ll hear, “Oh, but you should have seen them last week!” But this July is Perennials Month if ever there is one.
Hemerocallis – Daylilies: These are not true lilies, but one single, powerful genus which has been hybridized to produce thousands of exquisite cultivars. Hemerocallis societies abound, worldwide, and there is an extensive culture of collecting and displaying them – including several tours in Western New York that feature impressive daylily show gardens. Carol and Anthony Haj, of Lasting Dreams Farm, have 300 daylily varieties flowering right now. According to Anthony, “They love lots of water and heat. It’s a great year so far and I’ll think they’ll peak the middle of the month ...” At home, if you see the hundreds of buds that I am seeing, keep spraying that deer deterrent: It will be a magical daylily month.”
Hostas: Yes, they flower and in many it’s a great feature, but hostas will always be about foliage, first and foremost. Hosts of gardeners will agree there are no perennials more essential to garden design – especially but not only in shade – than hostas. It’s always a grand year for them but, wow, have they stood up tall and firmly so far. Love that water. The leaves are so perfect that I’m thinking the slugs froze last winter – or possibly drowned?
Filipendula rubrum (Queen of the Prairie): This will always be included in my garden plans. Soon the 5-foot drifts of pink plumes will fluff out over their strong stems and jagged leaves, and it will be a car-stopper. Then when it’s not, it will accept being cut in half and grow quietly behind something else.
Thalictrum: The taller Meadow Rues will be peaking soon (the 120-plus species including 3- to 8-foot beauties). I appreciate my delicate, white or lilac-flowering species, but now I’m most excited to see the huge (7-foot-plus) T. flavum purchased just last year – soft, yellow puffs!
Monarda (Bee Balm): On a tour or during Garden Walk Buffalo you can see the most amazing red Bee Balm, 5 feet high, in a 16th Street garden, and it’s not the only place our bee-pleasing friend is outdoing itself.
There are so many I missed mentioning, such as primulas (fabulous this season), irresistibly bright, white Shasta daisies in many sizes, and fantastic Astilbe cultivars that will be going strong for weeks, loving the wet soil. And there are so many more still to bloom during our long perennial season – through October, if you plan it right. Just wait for the coneflowers and Japanese anemones!
Get out on a tour, a walk, a driving trip and see what everyone else is growing. Flowering perennials have never looked better.
Sally Cunningham is a garden writer.