Trying a few new plants for mixed containers is something I look forward to every year. But when I’m at the nursery, I also consult my list of favourites — the ones that never let me down, look good all season and don’t use up my whole plant budget. These are my insurance plants in case the new ones don’t live up to their billing or just don’t work out.
Most on my list have been around for years, but I don’t think of them as boring — it all depends on what they’re paired with. As long as they meet these three criteria, they make it on my go-to list of easy, reliable container plants.
Sturdy, but not overbearing
Vigorous, fast-growing plants are welcome, but there are limits. Helichrysums, trailing petunias and sweet potato vines don’t make the cut, because if I turn my back on any of them, they often smother their neighbours and ruin the design by taking up too much space.
Looks great from the time it’s planted to first frost
I love flowering perennials, but I don’t use many in containers, because the majority bloom for three or four weeks at most. I rely on annuals, tender perennials and perennials grown mainly for their foliage, such as heucheras, ornamental grasses and hostas.
Must be easygoing
Plants that require minimal deadheading, tolerate heat and humidity, appreciate average soil moisture, and aren’t prone to mildew, rot or other fungal maladies make the list.
Containers with a mix of plants need an attention grabber — a focal point (a.k.a. “thriller”). This is usually a tall, bold specimen. Cannas and New Zealand flax (Phormium cvs.) are popular focal point plants, but if you’re looking for something less bulky, consider these.
Caladiums (Caladium bicolor cvs.)
Large, dramatic leaves, often mottled with pink, rose or white. Caladiums are stunning in a classy black pot with shade-tolerant flowering annuals in complementary colours. Most are about 24 inches (60 cm) tall, although there are dwarf varieties. Prefers dappled shade; full shade mutes the variegated leaf patterns. Tender tubers.
Gaura (Gaura lindheimeri)
Dainty pink or white blooms on arching stems that range in height from 18 to 36 inches (45 to 90 cm); a graceful, see-through plant. Zone 6 if drainage is excellent. Some of the newer cultivars may be less winter hardy. Sun.
Mystic Spires Blue salvia (Salvia ‘Balsalmip’)
This husky, intense blue salvia is similar to annual S. farinacea ‘Victoria’, which also works well in pots. Mystic Spires Blue, a tender perennial, is 18 to 24 inches (45 to 60 cm) tall; a butterfly and hummingbird magnet, too. Sun.
Mexican feather grass (Stipa tenuissima)
Arching clumps of narrow, soft, feathery leaves with a silvery sheen that are always in motion. The golden green flower plumes in midsummer earn it another common name: split-ends grass. Height ranges from 18 to 24 inches (45 to 60 cm). Sun; Zone 6.
Also consider using an upright conifer as a focal point in a large container. Look for a young plant of a standard-size conifer, not a dwarf plant—these are usually pricy. Upright yews, cedars, junipers and boxwoods are all good candidates. Once the shrub outgrows your container in a season or two, transplant it into your garden where it can grow to full size.
These are the team players (a.k.a. “fillers”) that bridge the space between a focal point plant and the trailers spilling over the edge of a pot. They’re also great on their own if you don’t want to make a mixed container. Mass several of one kind in a large container for a contemporary, dynamic look.
Many annuals fit this category — begonias, impatiens, petunias, zinnias, marigolds. I like these particular fillers because they offer a broad range of colours and form. They’re all mounding plants, ranging in height from 10 to 20 inches (25 to 50 cm). Those labelled “tender perennial” are usually grown as annuals in our climate, although they can be wintered over indoors as cuttings.
Angel-wing begonias (Begonia hybrids)
With glossy leaves and non-stop bloom, these are so floriferous and vigorous, they almost fit into the thriller category. Think of them as a fibrous begonia on steroids. Two of the most popular available today are Dragon Wing Red (B. ‘Bepared’) and Dragon Wing Pink (B. ‘Bepapink’). Sun to part shade; annual.
Swan River daisies (Brachyscome iberidifolia cvs.)
Dainty, ethereal, soft blue flowers with ferny foliage; sturdier than they look. Sun; annual.
Coleus (Solenostemon cvs.)
There’s a coleus for every colour palette: solid or variegated leaves in dusky maroon, eye-popping lime green, perky pink or warm bronze. Leaf shapes — scalloped, wavy, serrated, pebbly — add interest, too. Recent breeding means several of the new cultivars take full sun and are usually slow to flower (or are non-flowering), which may be a plus if you don’t care for the plants’ lavender flower spikes. Sun or shade, depending on the cultivar; tender perennial.
Heliotropes (Heliotropium arborescens cvs.)
Deliciously fragrant (a blend of cherry and vanilla), deep blue/violet or lavender clusters of flowers on plants with dark green, crinkled leaves. White cultivars are more fragrant but lack the punch of colour. The individual flowers of Simply Scentsational have lavender edges, a creamy centre and golden throat. Sun; annual.
Nemesias (Nemesia cvs.)
Similar to diascia, but available in more colours (including bicolours) and with a sturdier constitution. The blooms are reminiscent of snapdragons. Sun; annual or tender perennial.
Oxalis (Oxalis spiralis ssp. vulcanicola)
Although usually referred to as shamrock plants because of their emerald-green, large clover-like leaves, newer introductions have bronze, burgundy, plum or chartreuse foliage. Plants also feature tiny gold or white blooms, but these aren’t the point. Prefers moist soil. Sun or shade, depending on cultivar; tender perennial.
‘Profusion Orange’ zinnia (Zinnia angustifolia ‘Profusion Orange’)
Many zinnias make good container plants, but I single out this one because its blooms are a soft dusty orange that works well with myriad colour schemes. Requires more deadheading than other plants in this list. Sun; annual.
The grace notes
Trailing and spreading plants (a.k.a. “spillers”) soften the edges of pots, window boxes and hanging baskets. Don’t underestimate this category, and make sure to use more than one trailing plant in a container — one looks so lonely and miserly. Including several will take a straight-laced design and make it voluptuous, generous and luscious.
Calibrachoas (Calibrachoa cvs.)
Even though this self-cleaning, mini-petunia didn’t appear in garden centres until the early ’90s, there are now hundreds of named varieties available. Every year I think I’ll pass them up (is there a more ubiquitous container plant?), and then a new colour is introduced that catches my imagination. One year, it was the debut of yellow-and-white Lemon Slice, and I still rely on the older rich purple and soft terracotta shades. Sun; tender perennial.
‘Silver Falls’ dichondra (Dichondra argentea ‘Silver Falls’)
Tiny, fan-shaped silver leaves on long, skinny stems. Soft and graceful, it looks best with equally dainty blooms. Sun to part shade; tender perennial.
Lantanas (Lantana camara cvs.)
More sprawling than trailing, lantana is tropical punch on a stem — corals, hot pinks, yellows, creams and oranges abound. The domed flowerheads on Bandana Pink sport pink, yellow and cream florets; Desert Sunrise glows with yellow, gold and peach. Remarkably heat- and drought-tolerant plants that attract butterflies and hummingbirds. Sun; tender perennial.
Creeping wire vine (Muehlenbeckia complexa syn. axillaris)
Shiny, tiny green leaves on long, wiry stems. Neat and tidy plants — what boxwood might look like if it were a trailing plant. Sun to part shade; tender perennial.
Variegated potato vine (Solanum laxum ‘Album Variegatum’)
Olive green and gold variegated leaves interspersed with a few white flowers. A pleasant change from the usual variegated vines. Sun; tender perennial.
Trailing verbenas (Verbena cvs.)
Clusters of star-shaped purple, pink, lilac, peach and white flowers on arching stems. ‘Homestead Purple’ is a reliable variety with golf ball-sized flowers. Sun to part shade; tender perennial.
Don’t forget the foliage
Mixed containers benefit from a generous serving of foliage plants to act as a foil to colourful blooms. Without the calming tones and textures of interesting foliage, the overall design can be chaotic.
I aim for at least one-third foliage to two-thirds flowers in large mixed pots. In addition to the plants listed here, consider herbs such as parsley, sage and rosemary for filler plants. Hardy perennials that offer plenty of foliage options include heucheras, small hostas, ferns, ornamental grasses and tiarellas.
Hardy perennials can overwinter in frost-resistant containers in protected locations or transplant into garden beds at the end of the season.