Most homeowners have a bed dedicated to annual flowers, or pots planted with seasonal annual flowers that are strategically placed to direct guests to the front door. These same plants are also effective in providing shots of color in the perennial border.
Annual plants germinate from seed, grow, bloom and set seed in one season. There are cool season annuals and warm season annuals, and both deliver stunning color throughout the season. Warm season annuals bloom from mid-spring until frost and are traditionally planted after the first week of April. Constant bloom is a lot to ask of a plant, especially with our summer heat and humidity, but there are ways that you can keep these plants looking their best.
The first step is to choose varieties that are hardy and suited to the sun conditions in your garden. These old standbys are tried and true:
Geraniums (Pelargonium x hortorum). 12-36” t x 12-36” w. Who can resist the cheerful and colorful blooms of zonal Geraniums? Planted en masse, they provide a lavish display of color in garden spots with full sun and afternoon shade. Plant in rich, well drained soil and water regularly, but allow the soil to dry out slightly between watering. Promptly deadhead faded flowers and pinch back regularly to keep plants bushy.
Impatiens (Impatiens walleriana) - 6-24” t x 6-24” w. The jewel-tone colors of Impatiens light up partial to full shade areas. When planting, take care not to bury the crown of the plant and pinch back the stems of young plants to encourage branching. Fertilize only after the plants have begun to actively grow. If plants become leggy in mid-summer, shear them by 1/3, fertilize and they will be lush again in a few weeks.
Marigolds (Tagetes patula). 6-12” t x 6-9” w. Marigolds are easy, dependable annuals that require full sun and well drained soil. They come in yellow, orange, red and bi-colors, and feature single, semi-double and double flowers. They are susceptible to rot, so they are best planted after the spring rains have ceased and the soil has warmed. Deadhead spent flowers after they have dried; if the plants are not hybrids, throw the seed into the garden and new plants will emerge. Marigolds have a strong scent that is said to deter insects, so this is a good flower to plant around the vegetable garden too.
Petunias (Petunia spp.) - 9-12” t x 12-36” w. Petunias are easy care and bloom non-stop from spring to frost. Most petunias available for sale are hybrids and will be marked Grandiflora (large flowers 4” wide), Multiflora (2” wide flowers but more abundant blooms) and Cascading (pendulous stemmed varieties useful in hanging baskets or used as ground covers). Grow petunias in full sun with afternoon shade.
Wax Begonias (Semperflorens begonias) - 6-12” t x 6-12” w. Begonias come in a range of colors and they require little or no deadheading. Grow the green-leaved varieties in partial shade or indirect bright light; the bronze-leaved varieties will tolerate full sun.
Before placing plants in the ground, prepare the planting bed by adding 1-2” of compost to the bed. Sprinkle a little fertilizer over the surface and lightly dig it in. Place plants in the ground at the same depth they were in the original pot. To create a lush look, space plants close enough that they will barely touch at maturity. Spread a 1-2” layer of mulch to retain moisture and to give the bed a finished appearance.
To have the energy to provide continuous bloom, these plants are hungry for plant nutrients. There is a wide variety of balanced fertilizers available, but “slow release” products control the release of nutrients when soil temperatures and moisture are just right and most feed for 3-6 months. Supplementing with liquid feedings every 2-3 weeks will provide the nutrients annual plants need to thrive and bloom throughout the season.
Get plantings off to a good start by following a watering schedule for the first 30 days. My favorite watering schedule is to water every day for 3 days, every other day for 3 times, every third day for 3 times and then once a week for the remainder of the season.
Following these simple steps will keep plants healthy and beautiful and an enjoyment throughout the season.
Plant breeders are busy developing new and interesting plants for a demanding gardening public. One plant that garnered quite a bit of interest at the California Spring Trials is Celosia argentea ‘Kelos Fire' Series (shown in the photo). The long-lived flowers are bright, colorful, fluffy plumes that bloom from spring until frost. Flower colors include coral, chartreuse, magenta, violet, clear yellow and burgundy. They are set off by bright green leaves with reddish-purple veins. Growing 10-12” tall and 8-10” wide, they are happy planted outside in the garden or indoors as a houseplant. Celosia performs best in full sun with consistent moisture.