Ten Best Annuals for Sun

by Paul Schorr

The selection of plants suitable as annuals that do well in sunny areas is rather extensive when compared to those that do well in shade. This listing of top ten ‘sunny’ annuals is a selection of those that do extremely well in the St. Louis area; some may be tried and true and some fairly new in your garden. Enjoy your sunny garden! Some are perennial in frost-free areas.


Ageratum houstonianum
floss flower
Annual

Ageratums feature clusters of soft, cushiony flowers in white and shades of blue, purple, lavender and pink. The flowers will often cover the entire plant, especially in cooler weather. In hotter months and climates, the plants and flowers will benefit from light afternoon shade. The ‘Hawaii’ series is touted as blooming earlier in the season and having larger flowers than some other cultivars. Ageratum houstonianum ‘Blue Horizon’ has been selected as a Plant of Merit®. Taller varieties do well in a cutting bed and shorter cultivars work well in beds, borders and containers.

Sun: Full sun to part shade
Water: Medium
Height: 0.5 - 2.5 feet

Angelonia angustifolia SERENA MIXTURE
angelonia
Herbaceous perennial

Angelonia is also known as summer snapdragon. The flowers are fragrant and resemble small snapdragons in colors of white, pink, violet and purple, often with a contrasting color inside the eye or throat of the flower. They are an excellent choice for sunny areas, because once established, angelonias will tolerate heat, drought and humidity. The Angel Mist™ series (Simply Beautiful®) and Angelface® (Proven Winners®) are produced from cuttings and must be purchased as plants from your local bedding plant source each spring. Angelonia augustifolia ‘Serena Mixture’ may be started from seeds and has been selected as a Plant of Merit®. Use in beds or as an accent plant in containers.

Sun: Full sun
Water: Medium
Height: 0.75 - 1.5 feet

Catharanthus roseus
vinca
Herbaceous perennial

Vinca or periwinkle (sometimes called Madagascar periwinkle) is often confused with impatiens because of the similar appearance of their flowers. However, unlike impatiens, vinca thrives in full sun, intense heat and once established is drought tolerant. Vinca is a good candidate for the best annual in sunny areas. It will not tolerate cool, wet conditions, so for best results, delay planting this annual until mid-May in the St. Louis area. Vincas are somewhat prone to fungal diseases, so avoid overhead watering. Flower colors include white and shades of pink, purple, lavender and red. Vinca is great in beds and mixed plantings. ‘Mediterranean’ is a low growing series that can be used as an edger, in hanging baskets and as a trailer in containers. For sun and heat, you’ll love vinca.

Sun: Full sun to part shade
Water: Medium
Height: 0.5 - 1.5 feet

Celosia argentea var. cristata (Plumosa Group)
feather celosia
Herbaceous perennial

Commonly know as feather or plume celosia, this sun lover thrives well in the hot, humid summers of the St. Louis area and is drought tolerant. These celosias feature gracefully feathered plumes in shades of red, orange, yellow and pink that stand well above the foliage. A number of selections are available from dwarf to tall. Most of the colors in the ‘Fresh Look’ series have been selected as All-American Selection Winners®. Other Celosia argentea do equally well and should be considered for sunny areas including the Cristata (Cockscomb) Group and C. spicata. Cultivars of C. spicata feature narrower, feathery plumes on plants that can grow to 5 feet tall and stand erect without staking. Depending on your selection, celosia does well in beds, borders, cutting gardens and containers. Excellent as a cut or dried flower.

Sun: Full sun
Water: Medium
Height: 0.5 - 3 feet

Lantana camara
lantana
Broadleaf evergreen

Although a perennial evergreen in its native habitat, lantana is grown as a sun loving annual in the St. Louis area. Its disc-shaped flower heads attract hummingbirds and butterflies. Most cultivars feature multiple colors within each flower head. Colors range from gold, yellow, orange, pink, red, purple to white. The foliage is rather rough and finely toothed along the edge and the stems become somewhat woody by the end of the season. Lantana grows rapidly in hot weather, so plant them around the middle of May in the St. Louis area. The plants may need some light pruning to increase flowering and maintain their shape. A number of varieties are available both upright and trailing. Use in beds, containers and hanging baskets. Drought tolerant once established.

Sun: Full sun
Water: Medium
Height: 3 - 4 feet

Petunia (group)
petunia
Herbaceous perennial

The hybridization and introduction of new cultivars of petunias are an enhancement of an old favorite and merits their inclusion into the top ten of sun loving annuals. Petunias are available in a wide range of flower types from petite to large, single and ruffled to double and from trailing to upright. The flowers can be fragrant and come in a wide range of colors in solids, veined, edged and star patterns. Pinching back plantings in mid summer will keep them from becoming spindly and increase bloom production into the fall. The Fantasy series features profuse mini flowers on very compact weather resistant plants. The Waves, several of which have been designated All American Selections®, are trailing petunias that spread as much as 4 feet while maintaining a ground hugging growth habit. Visit your garden center and select a variety that suits your planting needs from beds to borders, containers and hanging baskets.

Sun: Full sun to part shade
Water: Medium
Height: 0.75 - 1 feet

Portulaca grandiflora
moss rose
Annual

This Portulaca is commonly known as moss rose because of its rose-like flowers and prostrate growth habit. This species features tiny, cylindrical leaves that are thick and succulent and flowers that are semi-double to double in a wide range of colors. Very few annuals can equal the performance of moss rose in sunny, hot droughty locations. Portulaca grandiflora is day length sensitive and flowers close up at night, but newer hybrid series such as Sundial, Tequila and Margarita are touted as staying open longer than the species. Use moss rose in beds, borders, rock gardens, containers and hanging baskets. Portulaca oleracea (purslane) is another Portulaca with similar features and uses.

Sun: Full sun
Water: Dry to medium
Height: 0.25 - 0.75 feet

Melampodium divaricatum
melampodium
Annual

Melampodium is also known as butter daisy because of its yellow/gold daisy-like flowers. The flowers are borne on mounded plants. This is another annual that grows and flowers well in hot and humid locations. Taller varieties can be used in cutting beds while shorter varieties are suited for beds, borders and containers. Melampodium divaricatum ‘Derby’ has been selected as a Plant of Merit®.

Sun: Full sun
Water: Medium
Height: 1 - 2 feet

Verbena x hybrida
garden verbena
Herbaceous perennial

Garden verbena is an herbaceous perennial that is grown as an annual in the St. Louis area and consists of varieties with both trailing and upright growth habits. Verbena does best in full sun and will tolerate some heat, humidity and drought but flowering may decline during periods of hot and dry conditions. Flowers appear to be flat or convex and can be up to 3” across with colors of white, pink, purple, blue, red and yellow. Select taller varieties for beds, containers and window boxes. Trailing varieties do well in hanging baskets, rock gardens and as an edging or ground cover. Verbena X hybrid ‘Imagination’ is an All American Selections® winner and a Plant of Merit®.

Sun: Full sun
Water: Medium
Height: 0.75 - 1.5 feet

Zinnia (group)
zinnia
Annual

This hybrid zinnia is a cross between Zinnia angustifolia and Zinnia elegans. The resulting cross combines the disease resistance and mounding growth habit of Z. augustifolia with the larger leaves and flowers of Z. elegans. The Profusion Series is a result of such a cross that does well in full sun, features good drought tolerance and needs less deadheading than many other zinnias. Flowers can be 2-3” across and come in a number of colors including white and shades of pink and orange. ‘Profusion Cherry', 'Profusion Orange' and 'Profusion White' have been chosen as All American Selections® Gold Medal winners, the highest honor given by AAS. An excellent bedding, border or combination plant.

Sun: Full sun
Water: Medium
Height: 0.5 - 4 feet