Annuals for Specific Locations
Maintenance
Fertilization
Most annuals do not require high levels of fertilizer, and will do well with just the initial fertilization during soil preparation. However, annual flowers often compete with trees, shrubs, and other members of their own species for moisture, nutrients, and sunlight. Any check in growth caused by insufficient nutrients can reduce the quality of the plant and its bloom. Therefore, it is usually better to make an additional application during the growing season. About 6 to 8 weeks after planting, apply about one-quarter to one-half the recommended rate of fertilizer to the flowerbed.
Heavy-feeding annuals demanding a rich soil may require additional treatments. Whenever a dry fertilizer is used, follow its application with a good watering to remove fertilizer from the foliage. Liquid fertilizers can also be used. It is recommended that plants be watered prior to fertilizing to insure the plants are actively growing and taking up nutrients.
Watering
Water plants as needed to maintain uniform soil moisture around the roots. Using organic mulches will help conserve soil moisture and retard weed growth. Deep, thorough watering every 7 to 10 days is much preferred over frequent, light watering. The former encourages a deep, penetrating root system. The amount and frequency will depend on natural rainfall, the type of annuals grown, and the quality of the soil. When possible, water early enough in the day so the foliage dries-off before nightfall, which will help prevent foliar diseases.
Mulching
After annuals are planted, it is suggested that a 2 to 3 inch layer of organic mulch be applied around the plants. If the correct choice is made, not only is it attractive, but it also helps to conserve soil moisture, retard weed growth, and keep the soil cooler. In the fall, the mulch can be incorporated into the soil adding organic matter and helping to improve soil structure.
Weeding
Weeding is one of the essential maintenance practices. Removing weeds not only keeps the bed attractive and tidy, but it also reduces competition for space and nutrients in the garden. Weeds should be removed as soon as you see them with shallow cultivation, or by hand pulling if they get larger. When mulch is used and the canopy of the flowerbed grows closed, weeds should become less of a problem.
Grooming
Many annuals require little additional maintenance to keep them attractive and blooming all summer. Some flowers’ heads fall off cleanly and do not need to be manually removed. Others require deadheading. Annuals strive to produce seed, and much of its energy is directed toward this task. If you deadhead, pick the spent flowers before they start to set seed, and the plant will produce more flowers in an effort to reach its ultimate goal. This practice keeps annuals in the flowering stage longer and usually results in a greater number of blooms. Annuals such as cosmos, geranium, marigold, salvia, zinnias, and other single stem flowers particularly benefit from this practice.
In order to control the growth of some annuals, pinching, or removing the growing tip, is suggested. This encourages a more compact plant with a neater growth habit. The tops of some plants, such as impatiens and petunia, may be cut back 6 to 8 inches after the first flush of flowers has subsided. This promotes a second flowering period in the fall. After cutting, fertilize if needed, and water well to encourage re-growth.
Use GardenersWeb Annual Selection Guide and Annual Planting Guide to ensure a splendid array of annual flowers.