Barbara J. Bromley, Mercer County Horticulturist 94
| ANNUALS: herbaceous plants which complete their life cycles (grow, flower, set seed, and die) within one year or growing season. Annuals include plants classed asflowers, vegetables, herbs, ground covers, and vines. |
This group may also include:
- tender perennials which are best treated as annuals in our hardiness zone;
- plants which flower the same year they are planted from seeds.
USES FOR ANNUAL PLANTS
- Edging or border for temporary and permanent gardens.
- Container planting: window boxes, pots, hanging baskets.
- Color accents
- Companion plants to improve color, health, or growth of vegetables.
- Trap plants to attract insect pest away from crops.
- Cutting: flowers for arrangements.
- Drying: for arrangements, wreaths, pressing
- Culinary: cooking
- Fragrance: especially in gardens for the blind
- Temporary gardens: short term decorative use for an area that is going to be something else in the future.
- Attract beneficial insects: insects such as lady bugs, flower flies, predaceous wasps, and others that feed on pollen and nectar when they’re not parasitizing or being predaceous on pest insects.
- Filler in established shrub and perennial beds. The first and second year some shrubs and other plants are in the ground there should be space between them if they have been positioned properly. Annuals can help fill this gap for the first couple of years.
- Mass plantings to offset building, roadways, or walks; to display corporate logos.
BED DESIGN
Flowerbeds can be created by laying garden hose or twine on the ground until the appropriate form is obtained. Use this marker as the pattern to edge out the bed.
Bed lines can be straight or rounded, but curved lines are more interesting. Planning the design on paper with the correct spacing for that plant will help assure that you have the right number of plants for your design. Keep taller annuals to the back of the border, and dwarfs and low annuals to the front.
Color selection is a personal preference. There are so many vibrant primary and soft pastel colors available, that many combinations are possible.
CULTURE
- SITE SELECTION: Individual plants have different requirements for sun, shade, partial sun, soil quality, and drainage. The majority of annuals prefer full sun, rich garden soil, and good drainage.
Other factors in choosing a place to plant are visibility, (will you be able to see and enjoy them when they are planted?) and accessibility for maintenance (will you be able to get to them to remove dead flowers, to weed, and to fertilize?). The average flower border should be no wider than 5 to 6 feet, so the middle can be accessed from both sides without stepping in the garden.
- SOIL PREPARATION: Most annuals need a soil that is loose enough for the roots to grow easily. Adding sand and organic matter to heavy (clay) soil will help loosen it. Organic matter also can be added to sandy soil. For the average garden bed, spread 1 inch of compost, peat moss, or well-rotted manure over the surface of the garden and spade or rototill in.
Have a soil test run to determine the pH or relative acidity. If lime is needed to raise the pH of an acid soil, apply according to soil test recommendations or use 3 to 5 lbs. of lime for each 100 sq. ft.
Annuals grow quickly and need fertilizer to nourish that growth. Use a complete fertilizer, either chemical or organic, such as 10-10-10, 5-10-10, or 5-10-5 applied at the rate of 2 lbs. per 100 sq. ft. and rake or spade in before planting. Sidedress at mid-season as required by individual plants. Plants may be sprayed with liquid seaweed, fish emulsion or manure or compost tea several times during the season.
- PLANTING – SEED: Follow seed packet instructions for distance apart and correct depth of planting. Timing of planting is also important, because some seeds are not frost or cold tolerant and must be sown when the soil is warm. Cover the seeds with fine soil and water thoroughly.
- PLANTING – TRANSPLANTS: Select healthy, robust seedlings in individual pots or 6-8 packs from your garden center. Reject any plants that appear stressed or infested with diseases or insects.
If you raise your own plants from seed make sure they are “hardened off” for a week before transplanting. Tender plants usually sunburn or die if not hardened off by stopping fertilizer applications, lowering temperature, and increased ventilation. Gradually expose them to outdoor conditions before the transplant date.
Purchase as close to planting day as possible, but be sure that plants that can’t tolerate frost aren’t planted too soon. Our frost-free date (central New Jersey) is usually near May 10. Each year varies. Don’t be so eager to get an early start that your plants will be damaged or killed by late frosts. Be prepared to cover those that may be threatened.
On an overcast day, planting can be done anytime. On a sunny day, transplant the seedlings in early morning or late afternoon so midday sun doesn’t damage them. After removing the plants from their container, check the root system. If the roots are tightly massed and take the form or the pot, they must be cut slightly or loosened a little so they will be able to grow into the surrounding soil.
Set the plants in the ground at the same depth they were in the pot and settle soil around them gently, being sure not to leave any air pockets around the roots.
Water thoroughly. Some gardeners use a transplant solution of water-soluble fertilizer, compost tea, or liquid seaweed mixed according to the label to reduce transplant shock.
MAINTENANCE
WATERING All plants need water to grow. For most annuals, watering at the rate of one inch of water per week will be enough. Use a rain gauge to determine how much rain has fallen, and reduce irrigation by that much. Some plants, such as California poppy, are content with less water. When irrigating, water thoroughly, preferably in the morning. Frequent, shallow sprinkling encourages shallow root systems and disease development.
MULCHING: Using organic mulches, such as grass clippings or shredded hardwood, or inorganic mulches, such as black plastic or polyethylene weed barrier, helps to maintain even soil moisture and temperature and to deter weeds. Be sure to use a little extra fertilizer (complete analysis, such as 10-6-4 or 10-10-l 0) when using woodchip mulches to offset the nitrogen used up in the decomposition process. Sometimes, organic mulches harbor pests such as earwigs and slugs, but this disadvantage is usually offset by the advantages of mulching.
PINCHING AND SHEARING Some annuals, such as sweet alyssum and lobelia, benefit from pinching their tips to encourage branching or to maintain form.
DEADHEADING Removal of spent flowers to keep plants productive and to maintain an attractive appearance is called “deadheading”. Marigolds, zinnias, calendula, and others benefit from this form of pruning. Do not deadhead from early September on if seed dispersal is desired for self-sowing or if seed is going to be harvested.
SIDE-DRESSING Annuals grow rapidly in order to complete their life cycle in one growing season. In late June or early July, applying a second application of fertilizer near, but not on, the plants, gives them a boost. Follow label directions for rate.
STAKING: Taller annuals, such as snapdragons and African marigolds, benefit from added support, so that heavy rain and wind can’t knock them over. Tomato cages, bamboo and metal stakes, and other forms of support are used.
PEST CONTROL Pests take many forms: weeds; insects; fungal, viral, and bacterial diseases; mites; mollusks (slugs); and animals. Pests seldom bother many annuals. Take care to keep weeds out of the flowerbed to avoid competition for available nutrients and water, especially while plants are small.
When problems arise, consult a good reference book from the library or bookstore or with a specialist at the Rutgers Cooperative Extension in your county. Some garden centers can also help. Most problems can be solved or controlled with cultural, biological, or mechanical means. Chemical attack should be used as a last resort when other methods fail.