Maritta Perry Grau
Frederick County Master Gardener
(4/1) For a burst of color in the garden, lasting from spring through late fall, annuals offer flowers and foliage that perform magnificently with a bit of care. Planted in drifts, in containers, or as a focal plant, annuals provide a wide array of choices for any garden spot.
An important component in any garden, from small balconies to large flower beds, annuals provide lots of blooms, color, and interesting foliage for that long stretch from spring through the first frost. If chosen wisely, they can thrive in a number of light and soil conditions, resist rabbit and deer, and provide nutrients for butterflies, bees, and other pollinators.
Have a sunny spot? If you have six hours or more of summer sun per day, take advantage of the magnificent new colors that add spark to old favorites, including geraniums (Pelargonium species), lantana (Lantana camara), and marigolds (Tagetes erecta). Consider adding height to a prominent garden spot with thunbergia (Thunbergia atlata), a sun-loving vine with profuse yellow, trumpet-shaped flowers.
Need color in a shady area? Often challenging, areas with low or partial light can be successfully planted with the right annual. The Beacon series of impatiens (Impatiens walleriana) is resistant to downy mildew, a condition that has bedeviled impatiens in the past. Other plants that thrive in partial shade, with at least four hours of sun per day, include torenia (Torenia fournieri), begonias (Begoniaceae sp.), calibrachoa (Calibrachoa parviflora), and lobelias (Lobelia erinus).
Interested in long-lasting blooms and magnificent color? Some annuals are especially noteworthy for their long blooming period from spring through fall. Consider penta (Pentas lanceolata), verbena (Verbena officinalis), portulaca (Portulaca oleracea), and salvia (Salvia officinalis) for a profusion of color throughout the seasons.
Want to add interesting foliage and textures? Foliage plants add a perfect note to flowering annuals. They are dramatic by themselves or interplanted with other annuals, offsetting the flowers as the perfect foil. Try the bushy, colorful foliage of Alternanthera (Alternanthera sp.), the big, heart-shaped leaves of caladium (Caladium sp.), or the brilliant contrasting colors of coleus (Coleus sp.).
Deer and rabbits nibbling your plants? Fortunately, some hungry wildlife species do ignore annuals such as ageratum (Ageratum houstonianum), alyssum (Lobularia spp.), begonias, and geraniums, to name a few. Check the University of Maryland Extension Service’s web site for a list of other wildlife-resistant plants, trees, and shrubs.
Worried about drought? While all annuals require water, some are more tolerant of dry spells. Try scaevola (Scaevola sp.), the Fairy Fan flower. Long-blooming, with a delightful draping habit, it’s attractive in containers with companion plants or on its own. Other drought-tolerant plants are Bidens (Bidens pilosa), lantana, and portulaca.
Want to attract pollinators? Annuals that are great pollen- and nectar-rich sources of nutrients include alyssum, angelonia, bacopa (Bacopa spp.), begonias, celosia (Celosia spp.), gazania (Gazania spp.), marigolds, and verbena. Plant them and your garden will become alive with the bustle of the pollinators.
Interested in container gardening? Think in terms of three levels: spikes, fillers, and drapes. For example, in a sunny area, you might fill a container with a mix of spikey dracaena, colorful snapdragon-like angelonia, and draping portulaca with profuse, rose-like flowers. For shade, you could consider tall coleus, impatiens for your filler, and scaevola or sweet potato vine for the draping effect.
Looking for new varieties of old favorites? Newcomers that will add dazzle to the garden include the unusual Tattoo series of vinca (don’t confuse this annual, Catharanthus roseus, with the periwinkle vinca vine), the magnificent Flame celosia, the Colorblast Mango Mojito portulaca, and the Pinkerbelle double wave petunia.
Photographs and additional information on each of these plants can be found on the Master Gardeners of Frederick Facebook page (see below). As always, Master Gardeners are pleased to help you identify good choices for your particular garden needs.
Once you’ve gotten those plants home, how/when do you get them in the ground?
Mother’s Day is the traditional cut-off date for expected frosts in Frederick County, at least until October. If it will be a few days before you can tuck your new plants into the ground, you might want to overnight them in the garage or shed, bringing them out each day to help "harden" them to the outdoor weather. However, if you do plant spring or summer annuals a couple of weeks earlier than this year’s expected last frost date, watch for any predicted cold weather and cover plants accordingly. Even if temperatures are predicted to be slightly above freezing, close to the ground you may still having freezing temperatures. You might want to use row covers, even bed sheets or old quilts to protect your plants through the night time. Just be sure to take the covers off early in the morning; otherwise, the plants might bake under the covers in the heat of the day.
As to depth, make your hole about twice as wide and deep as the width/depth of the seedling pot. Ensure that the soil is loose, with no obstructing rocks or twigs in the hole. Pour in approximately one-fourth to one-half cup of diluted fertilizer (I like the powdery kind that is mixed with water) and let it absorb into the soil. Then place the plant in the hole and gently but firmly pack the soil around the plant to the point at which the stem was emerging from the seedling pot. You may want to pour on a little more fertilizer once the plant is solidly in the ground. You’ll want to check a gardening book or the Internet to see how frequently, if at all, the plant should be fertilized during the spring and summer: some plants produce more foliage than blooms if fertilized too frequently or too heavily. I usually fertilize annuals and perennials until late summer; those that bloom just in the spring usually don’t seem to need a boost.
Annuals are great choices to camouflage dying spring perennials or slowly growing/spreading summer/fall perennials. Since annuals are usually shallow-rooted, they can often be planted among spring- or fall-blooming perennials to fill in the gaps after perennials die down or, later in the season, until they bloom. When my daffodils have finished blooming but the foliage is still growing, I sometimes intersperse them with ageratum, petunias, marigolds, or alyssum. If I want taller-growing plants, I may choose giant zinnias or marigolds or other tall flowers. Sometimes I use various herbs, too.
Beware of invasive plants, even among annuals! We want to be vigilant about plants because, as the <Maryland.gov> website explains, "Invasive plants threaten native plant health and biodiversity in both agricultural and natural systems." The website lists many more shrubs, trees, and vines than it does flowers, but among those plants are yellow iris, fumewort (Corydalis incisa), fig buttercup (Ficaria verna), and shining cranesbill (Geranium lucidum). Purple morning glory (Ipomea purpurea) sometimes listed as invasive, and with reason: It grows quickly and its seed pods are prodigious. However, for me, it has three redeeming qualities: One, seeds sprout primarily near the mother plant and are very easy to pull out; two, it is beautiful when the sun shines through its deep, rich purple blossoms; and three, several vines growing up a trellis or string guides do create a lovely dappled shade. I can’t help myself; I still have to let a
couple of vines grow every summer. Besides, they remind me of the morning glory vines my grandmother grew every summer to shade her back porch.
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