Annual flowering plants pep up landscape areas and container gardens. Using them to design garden color spots is like opening a box of paints to render a landscape painting. Annual flowering plants lend brightness and vividness to garden landscapes. August, when it's easy to notice bare or blah spots, is the best time for Roanoke-area gardeners to begin designing next summer's hot spots. An August plan helps resist impulse buying in March and April.
Available in varieties of colors, shades of red, yellow, and white annual flowering plants attract notice and are dynamic in various combinations. Individual varieties also satisfy requirements for various design characteristics such as height, width, size, shape, and texture.
Annual Flowering Plant Suggestions for Full-sun Color Spots
- Groundcovers
Ipomoea batatas (sweet potato vine), part of the morning glory family, works best in full sun and at the edges or bottoms of plantings. These plants are marginally deer-resistant. They are not the first food choice of native Virginia white-tailed deer, therefore there is merit in planting them.
Ipomoea Illusion™ 'Emerald Lace' is valued for its lime green foliage and deeply toothed leaves, while Ipomoea Sweet Caroline™ 'Bewitched' exhibits frosty purple, slightly larger, toothed leaves with a semi-erect habit.
Ipomoea South of the Border™ series includes 'Guacamole' that has large light green leaves tinted with light purple veins. 'Refried Beans' has slightly smaller leaves colored in autumnal shades of yellow and bronze. Hort Couture™ publicity describes 'Chihuahua' that grows in miniature lime green clumps, as exceptional. Annual flowerbeds at the PGA TOUR FedExCup Greenbrier Classic featured this sweet potato vine as a groundcover.
- Groundcovers or Mid-bed Plantings
Vinca or Madagascar periwinkle (Catharantus roseus) and New Guinea impatiens (Impatiens hawkeri) provide beds of season-long flowers. Vinca loves dry climates and sandy soils; New Guinea impatiens does not like wet feet and tolerates more sun than its cousin known as busy lizzie or bedding impatiens (Impatiens walleriana).
The Cora™ series of vinca or Madagascar periwinkle needs warm temperatures, regular irrigation, good drainage, and full sun for best performance. Allan Armitage in his "Manual of Annuals, Biennials, and Half-Hardy Perennials" (2001, p.138) says that "if Vinca receives the same amount of water that the lawn receives (assuming the lawn is green), it will likely rot and die." The Cora™ series is supposed to thrive better than most other vincas in damp and moist conditions. Cora™ 'Punch,' with bright magenta-fuchsia flowers, and Cora™ 'White,' with pure white flowers, make a great looking combination.
Posh™ New Guinea impatiens (Impatiens hawkeri), available in a variety of hot colors, was a feature in plantings at the PGA TOUR FedExCup Greenbrier Classic. According to Jim Monroe, owner of Greenbrier Nurseries, these annuals are among Hort Couture's™ series of genetically improved Impatiens plants that are prolific growers which grow well in both landscapes and mixed containers. Although these impatiens plants can withstand more sun than the bedding types, some partial shade is necessary in locales like the Roanoke area. They are heavy drinkers but do not do well in wet soil.
- Backbone of Small Beds or Middle of Larger Plantings
Celosia (Celosia argentea) 'Fresh Look Yellow' along with 'Fresh Look Red' and 'Fresk Look Gold' are All-America Selections winners. They belong to the plumosa group of celosias and possess long, slender terminal and axillary spikes. Plants tolerate heat, humidity, and severe weather.
Plants belonging to the 'Fresh Look' series always look fresh and need little or no grooming. The central plume can be 9 inches tall and 6 inches wide and overall, it may reach a height of about 12 to 17 inches and spread about 12 to 15 inches. 'Fresh Look' series plants grow numerous side shoots that cover mature blooms and eliminate deadheading.
- Specimen Plants of Mid-bed Clumps
Fountain Grass (Pennisetum setaceum) usually grows three to four feet tall and possesses foxtail-like inflorescences in shades of red to burgundy. Varieties are 'Purpureum' – sometimes called 'Atropureum' – that has wide dark purple leaves, up to one inch wide, and 'Rubrum' – sometimes labeled 'Cupreum' – has leaves and inflorescences that are somewhat creamy, but the plant grows larger than 'Purpureum.' According to Armitage (p. 384), "The two are constantly confused: unless they were grown side-by-side, they are probably mislabeled."
Pennisetum 'Fireworks' is a new variety that grows to about 4 feet tall and produces leaf blades variegated with longitudinal stripes of white, green, and burgundy. They provide purple tassels in late summer that rise above the foliage. However, the variegation fades in bright light and as the season progresses.
No matter what the labels say, these grasses bloom throughout the summer with flowering stems dominating clumps of lush red to purple tinged foliage. They need to be planted in full sun and watered sparingly.
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