Revving up your garden with seasonal color

Story and Photos by Troy B. Marden

Annuals often get a bad rap. “They’re too costly!” “I have to plant them every year!” “I don’t want all of that maintenance!” These and many others are among the litany of excuses I hear from people not planting more annuals in their gardens. The truth is, annuals, when not used strictly for bedding, but instead mixed in amongst perennials and other garden plants, can rev up the garden for an entire season with little effort on the part of the gardener. And, when you consider their cost spread out over the entire growing season, there are few perennials – or even shrubs – that give you as much bang for your buck!

A modern take on traditional bedding, the gardeners at Cheekwood, in Nashville, create stunning displays of annuals every summer. These are changed out with Viola and pansies (V. x wittrockiana) in winter to provide year-round color and interest.

Annuals carry us through the midsummer bloom gap we experience across much of the South, when the main season perennials have long finished, but autumn’s Aster, Anemone, and other fall bloomers have yet to start their show. During these dog days of summer, tropical and subtropical plants – which many of our most common annuals are – thrive in the heat and humidity of the season. Smart choices at the garden center in April and May will make for a spectacular show come July, August, and well into autumn.

An unusual tropical, rex begonia vine with its colorful and ornately patterned leaves is not a begonia at all. Cissus discolor is perfect for draping over the side of a pot or to climb a sturdier centerpiece plant.

The first habit that must be broken when choosing annuals is going directly to the flats of standard bedding plants at the garden center. Gone are the days of planting flat upon flat of Impatiens, Petunia, Vinca, and marigolds (Tagetes spp.) in beds – or at the very least, large swaths within a bed –dedicated solely to one species. Not only is this a very commercial-looking approach that says “office park” rather than, “a gardener lives here,” but it can be extremely problematic if a pest or disease takes hold. 

When a cedar tree had to be removed from this garden, the stump was left standing and a large basket was attached to the top. Now, each spring it is planted with a variety of annuals that put on a spectacular show – summer until frost.

Downy mildew in impatiens is a textbook example of a serious disease problem in mass plantings over the past five or so years, as homeowners across the country experienced the total midsummer devastation of impatiens by this nearly unstoppable foe. It’s quite disheartening to walk out one July morning and find that almost overnight, the 15 flats of impatiens you so diligently planted in May have collapsed into a mushy heap, the beds bare for the remainder of the summer. At the very least, in a mixed planting, plants not susceptible to downy mildew will survive and you’ll be left with something to carry on the show.

A striking combination of blue daze (Evolvulus glomeratus) and ornamental peppers adds color and texture to empty space in a perennial bed.

And so I advocate, whenever and wherever possible, the mixed planting approach: using annuals of all shapes and sizes to fill the gaps between other plants and doing away with mass plantings of one variety altogether. It is a more pleasing and vastly more interesting effect, and it keeps interest going in the garden from summer right on through frost. Among clumps of daylilies (Hemerocallis hybrids), phlox (P. paniculata), black-eyed Susan (Rudbeckia fulgida), and purple coneflower (Echinacea purpurea), I plant coleus (Solenostemon scutellarioides), Lantana, ornamental peppers, and annual grasses, such as purple fountain grass (Pennisetum setaceum ‘Rubrum’). In drier parts of the garden, I opt for Texas sage (Salvia greggii), zinnias (Z. elegans), moss rose (Portulaca grandiflora), and Cosmos to carry the show through the summer with limited irrigation.

Elephant ears, such as this dark-leafed beauty called ‘Diamond Head’, make perfect architectural centerpieces for large containers and can be underplanted with a variety of colorful accent plants.

Annual flowers and foliage plants are indispensable in containers, too. Mixed containers planted with a variety of annuals in beautiful combinations can be used to great effect for window boxes, containers on the porch, as well as containers used as accents around the garden. Elephant ears (Alocasia, Colocasia, Xanthosoma) and other tropical plants make striking container subjects. Those with upright forms allow creative underplantings. Fanflower (Scaevola spp.); sweetpotato vine (Ipomoea batatas cvs.); trailing Petunia, such as the Wave series; cascading vinca (Catharanthus roseus), such as the Cora Cascade series; Bonfire begonia (B. boliviensis ‘Nzcone’), and many others will provide summer-long color under more structural or architectural centerpiece plants.

Even broken pots can be beautiful! Whether on its side in the garden with annuals “spilling out” or used on a terrace, as seen here, a broken pot can be the perfect inspiration for a creative and unique focal point.

Vines, such as Fiona Sunrise jasmine (Jasminum officinale ‘Frojas’), mandevilla (Mandevilla spp. and hybrids), rex begonia vine (Cissus discolor), and black-eyed Susan vine (Thunbergia alata) can be used to climb gently around larger plants, but will also send their runners cascading over the side of a container, mixing and mingling with their neighbors as they go.

A hot color combination that is equally heat tolerant: Blanketflower (Gaillardia ‘Oranges and Lemons’) and creeping zinnia (Sanvitalia procumbens) thrive in summer’s heat while adding a bold splash of color to the garden.

Annuals do require a bit of maintenance. Regular deadheading will keep them flowering profusely. Many – especially those that flower from the beginning of the season to the end –will benefit greatly from regular applications of fertilizer throughout the summer. This is especially true for annuals growing in containers, where every watering or rainfall leaches nutrients from the soil. Occasional pruning or cutting back during the summer will encourage luxurious growth, branching, and, in the end, even more blooms or greater production of colorful foliage.

Fiona Sunrise jasmine (Jasmine officinale ‘Frojas’) provides a spectacular golden accent in the garden or in a pot. Paired with dark-leafed plants such as ‘Maple Sugar’ hibiscus (H. acetosella ‘Maple Sugar’), it truly shines!

While this may seem like a lot of work, the entire garden will benefit from these practices and the relatively small investment in those annuals at the beginning of the season will pay off many times over as they brighten the garden from spring until frost.

So, be bold! Rev your gardening engines and push your gardens into annual overdrive!

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