For those who garden because they love flowers, they want their gardens to spill over with blossoms from early spring until the snow flies. In order to achieve this, many gardeners will resort to planting only annual flowers or interspersing annuals with perennials.
But now there are some perennials available on the market – many of which will grow in Zones 2-4 – and guarantee continuous blooms for at least a month. Some will bloom for more than four weeks. By perennial definition, an ever-bloomer is a plant that blooms for a minimum of eight weeks. From a flower production aspect, two months is a long time and covers most of the summer in our zone.
The production of flowers uses a tremendous amount of energy from the plant because the flower houses the seed. Because a perennial continues to bloom from year to year, energy must also be reserved for the growth and survival of the plant. This is why perennials typically have such short bloom times.
With ever-blooming perennials some species require the removal of the spent flowers, to encourage continued blooms. This is called deadheading. When a plant starts to produce seeds, a hormone is released within the plant that tells the plant to stop flowering. Removing flowers as soon as they begin to decline prevents the release of this hormone, encouraging the pant to continue to bloom.
The following is a list of basic, widely available ever-blooming perennials suitable for Zone 3. This is just a short list and there are new varieties are being developed and released each year so read the tags when you are at the nursery.
Bell Flower – many varieties and heights available; bluish purple, pink or white blooms; make great border plants (front or back borders depending on height).
Centaurea – also known as cornflower or bachelor buttons; many interesting varieties with different leaves and/or flowers; some varieties can be hard to find.
Corydalis – available in blue, purple or yellow; starts blooming in spring; looks similar to Columbine.
Perennial geranium – very versatile in soil preference; can be planted in full sun to partial shade; available in colours ranging from blue, purple to white.
Salvia – hardy perennials that are available in a large selection of varieties and colours; very versatile to soil and light conditions; highly recommended.
Scabiosa (Pincushion flower) – many varieties available; likes full sun; once you have one variety you’ll want more. Use multiple sources to find different varieties.
Spiderwort – likes moist soils; mine are planted in the bog garden; available in blue, pink and purple.
Speedwell (Veronica) – attracts butterflies; many varieties available; blooms for two months; read the tags because different varieties start blooming at different times of the season.
Tickseed – yellow daisy like flowers; multiple heights available so check the tags.
Verbena – many varieties available, ranging in plant formation (mat-like to upright) and colours (pinks, purple and white); attracts butterflies; can have many varieties in same garden and will look like different plants.
Yarrow – many colours available; tall great for cut flowers; can be invasive in very fertile soil conditions.