Flowering plants include hundreds of species
A multitude of alliums, commonly known as onions or garlic (of which many are ornamental) can also be included in a garden. They can be planted in the fall as bulbs or throughout the growing season as potted perennials. With the right selection, these plants can flower from late spring to late fall. This author likes to leave them up long after flowering and have turned shades of brown. However, to control self-sowers (i.e. self-seeders), they should be removed sooner. Although many do seed quite willingly, other newer cultivars remain clumping. Pollinators visit these quite regularly, too.
The ‘Globemasters’ and ‘Purple Sensations’ of this genus are the reliably big bloomers in this family; however, Allium sphaerocephalon (round-headed leek) and A. caeruleum (azure-flowered garlic) can also be planted as they are smaller and add colour and interest to the summer landscape border.
Camassia leichtlinii (camass) is gaining popularity amongst landscapers and garden planners as a native perennial bulb (in Canada, it is native to the West Coast and south to California). Spring-flowering, colours range from white and cream to blue or purple, reaching a height of 800 mm (31.5 in.). Camassia quamash (quamash, small camass) is smaller with violet-blue flowers reaching a height of 350 mm (13.7 in.). Reliably hardy in southern Ontario, these bulbs naturalize over time. They make a great addition to the spring/early summer landscape border, as they are not seen regularly. The foliage lasts well-over time—even as it dies back—in comparison to tulip or daffodil foliage.
Perennial possibilities are endless
This author has a hard time choosing a favourite perennial, but instead has a consistent top 20. For instance, if space is available in the garden, she recommends a hellebore be planted. These are not native plants, but they are reliably hardy and evergreen, and provide early flowering in mid- to late-winter, depending on conditions.
Helleborus foetidus (stinking hellebore) stand up well through spring and summer, and when deadheaded by fall, they keep going strong. Helleborus x hybridus ‘Blue Lady’ (hellebore, Lenten rose) is another strong performer and will self-sow after many years in the garden. These plants also make for a great groundcover over invasive Hedera helix (English ivy) or Vinca minor (periwinkle). There are many for landscapers to choose from with newer introductions having flowers facing upward.
In this author’s experience, it is important for landscapers to focus on a key set of native plants, or those indigenous to the northeastern U.S., as they have proven to do well in northerly gardens. Gillenia trifoliata (Bowman’s root) now known as Porteranthus trifoliata is a native perennial that becomes nearly woody, or more shrub-like as it matures. Blooms are five-petalled starry white with distinctive red stems from May to July. They offer great fall colour and stand up well through winter; however, wind and hard rain has been known to knock down its outer stems. This perennial takes a few years to establish, full-sun to part-shade, but is well worth the wait.
Amsonia tabernaemontana (blue star) and A. hubrichtii (blue star) are native to central and northeastern U.S. These species of herbaceous perennials are four-season workhorses. The blue star flowers for which they are known are attractive to pollinators. The foliage turns orange to yellow in the fall and grows well in full-sun to part-shade. Baptisia australis ‘Purple Smoke’ (false indigo) is a great companion plant to the Amsonia. Baptisia is a deeply rooted perennial that has excellent drought tolerance once it is established. Its attractive foliage remains intact until late winter when it essentially lifts from the crown and becomes like tumbleweed. Both are excellent choices for today’s changing climate.
Landscapers should also include a representative of the Asclepias species in every garden. This author has Asclepias tuberosa (butterfly weed) in a container on a deck with Asclepias incarnata ‘Ice ballet’ (swamp milkweed) where bees and butterflies visit all summer. In the fall, ladybird beetle larvae feed on the aphids, which are common to these perennials. Milkweeds are an important food source to many insects, including as larval host to Monarch and Grey Hairstreak butterflies. Asclepias tuberosa is one of possibly two orange-flowering perennials in Ontario, ranging from Ontario to Newfoundland. The benefits of including these native plants in a landscape are countless, as they are not only attractive, but also provide food and habitat to many beneficial insect populations.
Liatris spicata (dense blazing star) is found throughout the eastern U.S., but limited in Canada to southwestern Ontario, growing only in a few remaining tallgrass prairie habitats. In fact, this perennial is considered a threatened species in Ontario. Liatris sp. make excellent additions to the home and urban garden; they can even be used for container gardens. Members of the aster family, the flower spike is densely packed with purple flowers, which open along the stem from the top down. This perennial is drought and humidity tolerant, but not keen on water in the winter; therefore, when positioning, it is important to ensure good drainage.
Liatris pycnostachya (prairie blazing star) is probably the tallest species in cultivation, while L. cylindracea (cylindric, slender blazing star) is native throughout Ontario. All of these perennials are attractive to insect pollinators and birds, specifically hummingbirds.
