We gardeners love our perennials – they’re versatile and dependable, act as a superb backdrop for plantings of annuals and bring a feeling of permanence to flower borders. Whether you garden on half an acre or the smallest of yards, there’s room for a few of these plants in your garden.
No shrinking violets, these plants can provide an exuberant display of colour, attractive foliage or even tantalizing fragrance. In particular, these eight old-fashioned favourites have been with us for years – some are no-care, some are low-care and a few require pampering. Provide them with their needs and wants and they’ll reward you with a summertime of fabulous blooms!
Mountain Bluet (Centaurea montana)
A prolific bloomer, mountain bluet (a.k.a. perennial cornflower) bears blue, thistle-like flowers above dusty-grey foliage. A vigorous clump-forming perennial that spreads by rhizomes, Centaurea montana thrives in full sun or partial shade, in average to rich soil. Easy to grow, it has a preference for cool temperatures. Once established, it will tolerate some drought conditions.
An early bloomer, C. montana will continue to produce flowers well into midsummer on plants up to 40 to 45 centimetres in height. Deadhead regularly to prolong flowering and to keep the plant looking attractive. C. montana self-seeds readily; deadheading not only prolongs blooming, but will keep the plant in check. The plants get somewhat leggy – after blooming, cut the foliage back by a third to eliminate unsightly, gangly stems. This step also encourages a second round of flowers in the fall.
Clumps should be divided every two to three years in spring or fall to keep the plants contained and healthy. In some areas, spider mites may be a problem. Propagation is by division or seeding. Hardy in zones 3 to 8.
Tickseed (Coreopsis spp.)
The perennial species of Coreopsis, also known as tickseed, produce yellow, daisy-like flowers that do their best to brighten up any corner of your garden. These trouble-free and drought-resistant plants thrive and bloom most profusely in a sunny spot. They bloom from early summer to fall, and may seed prolifically, so deadhead to keep the plants contained.
C. verticillata, commonly known as threadleaf coreopsis, has golden-yellow flowers and narrow, finely divided leaves. C. grandiflora, or big-flowered coreopsis has a profusion of golden-yellow flowers, five to eight centimetres across, that make excellent cut flowers to add to your summer bouquet. For superb colour, try ‘Lime Rock Ruby’ coreopsis, a red-flowered variety that is being planted at VanDusen Botanical Garden this year.
Propagation of coreopsis is by division, cuttings or seed. Space plants 45 centimetres apart. Cut the plants back by a third after blooming. Clumps may be divided in early spring or early fall. Hardy in zones 3 to 8.
Canterbury Bells (Campanula medium)
Ring in the summer with campanula bells. There are many species of Campanula available, but my all-time favourite is C. medium, a biennial bellflower with large showy blooms in shades of pink, blue, lavender and white. This is the classic cottage-garden variety with large, bell-shaped flowers. Plants grow to a height of 60 to 90 centimetres and may require some staking. C. medium calycanthema is a “cup and saucer” variety that bears double flowers, in shades of white, pink and purple. Extremely hardy, these are wonderful massed in borders, and make excellent, long-lasting cut flowers.
In addition, I recommend the following: C. carpatica (tussock bellflower or Carpathian harebell) forms small, round 10- to 15-centimetre clumps of foliage with blue, lavender or white cupped flowers that die back to the ground.
C. glomerata (clustered bellflower) forms small mounds of dense foliage with blue flowers.
C. persicifolia (peach-leaved bellflower) is evergreen and has two- to three-centimetre white or blue flowers on stems up to 1.5 metres tall. Tidy these up in the fall, but don’t cut them back to the ground.
Plant bellflowers in full sun or light shade in well-drained soil that has some organic material worked in. Water well during dry periods. Propagate by division, cuttings or seed. Divide established clumps in early spring or fall. Plants are hardy in zones 2 to 8.
Daylilies (Hemerocallis cultivars)
Practically indestructible, daylilies are sensational in midsummer when other flowers languish from the heat. As their name suggests, each bloom lasts only one day; however, an abundance of buds are produced over a period of three to four weeks. The blooming season can be extended from early summer to fall by planting early-, mid- and late-blooming cultivars.
Daylilies grow in full sun or partial shade, and thrive in any reasonable garden soil. When planting, provide enough room for them to spread – at least 50 centimetres between clumps. Daylily foliage is attractive as well, with long, arching leaves arranged in fans.
Among the hundreds of daylily cultivars, you will find such colour variations as peach, pale yellow, apricot, orange, orange-red, deep magenta, pink and lavender, as well as contrasting colours, and single or double flowers. Heights vary from 30 centimetres to 1.5 metres. ‘Stella de Oro,’ a dwarf variety, is an exceptionally long-blooming cultivar that produces an abundance of yellow-gold flowers throughout the summer.
What’s new with daylilies? The American Hemerocallis Society has a number of 2002 award-winners that will knock your socks off! Watch for Primal Scream, Ruby Spider, Peach Magnolia and Curly Cinnamon Windmill to make the scene and spice up your garden.
Once established, daylilies require a minimum of care and are seldom troubled by diseases. Daylily roots are effective soil binders, and are ideal mass-planted on slopes or banks. Clumps will crowd each other out, so divide them every four or five years, in spring or early fall. Hardy in zones 3 to 9.
Hollyhock (Alcea rosea or Althaea rosea)
Towering spires of hollyhock are real traffic stoppers, and have been a popular perennial with gardeners for years. This old-fashioned flower has tall spikes of blooms, single or double powder-puffs, in a wide range of colours, including white, pale yellow, pink, apricot, red, maroon and near-black.
Treat this short-lived perennial like a biennial – sow the seed in summer for plants that flower the following year. Allow some plants to self-seed for another generation of flowers.
Plant in well-drained soil in a sunny location, and provide adequate water during the growing season. If possible, plant hollyhocks against a trellis or at the back of the border. Plants grow to a height of 1.5 to two metres, with blossoms opening from the bottom and working their way upwards along the stem. Because of their height, hollyhocks tend to flop – but that is part of their natural charm.
Plants grown on the coast invariably get rust that affects the undersides of the leaves. To avoid this, hollyhocks can be grown as annuals. Cultivars such as ‘Majorette’ and ‘Summer Carnival’ flower their first season if sown early in the year.
For diehard hollyhock fans that can live with a little rust, planting hollyhocks at the back of the garden makes bare stems less noticeable. Rust will yellow the leaves and cause them to fall prematurely, but won’t kill the plant. Avoid overhead watering so the leaves don’t get wet. Also remove infected leaves so the disease doesn’t spread. Fall cleanup is an important deterrent against rust, as the fungus overwinters in ground debris.
Another solution would be to try a rust- resistant cultivar, such as ‘Antwerp,’ which is available from Thompson & Morgan. Hardy in zones 3 to 9.
Garden Phlox (Phlox paniculata)
Fragrant garden phlox is another traditional favourite that will provide a stunning display throughout the summer. Available in a wide range of colours including pink, lavender, purple, crimson, orange and white – even some bi-colours with contrasting eyes. These plants look spectacular when mass-planted, and make excellent cut flowers.
Plant in full sun or light shade in soil enriched with organic material. Water during the growing season. Clumps spread rapidly and should be divided every few years in spring or fall to contain them and keep them vigorous. A site with good air circulation is very important as some plants are subject to powdery mildew. Thin out stems to increase air circulation and eliminate overhead watering. As with hollyhock, cleaning fall debris will help reduce overwintering fungal spores.
Some varieties resistant to powdery mildew include ‘Robert Poore,’ with deep pinkish-purple flowers; ‘Bright Eyes,’ with salmon-pink flowers; and ‘David,’ with pure-white giant flower heads. Heights range from one to 1.5 metres.
Remove spent heads after flowering, and cut the stems back in fall. Propagate by digging and dividing clumps in spring for fall. Hardy in zones 2 to 9.
Shasta Daisy (Leucanthemum x superbum)
With their fresh white flowers, Shasta daisies provide relief from the jumble of vibrant summer colour. Particularly beautiful when grown as drifts in a border, they also make excellent cut flowers, with blooms that last well over a week.
Flowers come in single, semi-double and double, as well as deeply lobed and fringed petals. Single-flowered varieties need full sun, but doubles grow in partial shade. Any ordinary, well-drained soil may be used.
Flowers grow from five to 12 centimetres wide, with stiff, erect stems that stand well above compact green foliage. Expect blooms from early to midsummer. Plants grow to an average of 60 to 90 centimetres in height. Taller cultivars may require staking. Deadhead to prolong blooming.
‘Little Princess’ is a semi-dwarf that grows to a height of 30 centimetres, and the All American Winner ‘Snow Lady’ grows to a height of 25 centimetres. Either of these beauties would be perfect for the front of your flower border.
Propagation is by division in early fall or spring. Hardy in zones 4 to 8.
Named after Achilles of Greek mythology, these vigorous, drought-resistant plants have flat 10- to 15-centimetre clusters of flowers on stiff stems. The blooms are long-lasting as cut flowers, and exceptional dried, as they hold their colour well.
A. millefolium, or common yarrow, has fern-like, aromatic foliage and white, sometimes pink, flowers, while A. millefolium ‘Paprika’ has striking dusty-red flowers with yellow centres.
In the past few years, some outstanding hybrids have been developed of A. millefolium. ‘Summer Pastels,’ for example, offers flowers in soft shades of cream, butter and lemon, plus varying shades of salmon, orange, red, mustard, ochre and bronze. These flowers are beautiful in borders or containers. ‘Walter Funcke’ has large clumps of orange-red flowers on silver-tinted foliage. ‘Terracotta,’ with its dusky-orange flowers that turn yellow on silver foliage, is “hot” this season.
Plant yarrow in a sunny, dry location. It tolerates poor soil, but does best in a well-drained soil. Height from 45 to 90 centimetres. Flowers intermittently from summer to early fall.
Once established, yarrows require very little care to thrive. Poor air circulation, however, can lead to powdery mildew. Deadhead for continuous blooms. Yarrows spread vigorously, so plants require division every three to five years, and should be divided in spring or early fall. Propagation by division, seed or cuttings. Hardy in zones 2 to 10.
Judy Heyer is a freelance writer and avid gardener living on the beautiful Sunshine Coast.