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Landscaping Tips

Landscaping Tips

Annuals 101

What Is an Annual?

impatiens

The term annual is applied to garden flowers that complete their life cycle in the span of one growing season. This means they come up in the spring, grow, flower, set seed and then die after the frosts in the fall.

There are many plants used as annuals in northern climates that are in fact perennial if planted far enough south where they do not experience the damaging effects of frost. These are termed tender perennials used as annuals. These include such plants as geranium, impatiens, vinca, coleus, and lantana. If one wants to save these plants from year to year, they would need to be dug up, potted and brought indoors or cuttings taken from the plants, rooted, and the resulting plants overwintered indoors.

There are a number of annuals that may act like perennials because of the large amount of seed they drop in the fall. This seed remains viable over the winter and new plants emerge in and around the area where the annual was planted the previous season. Plants like cleome, snapdragon, amaranth, cosmos, and petunia are examples.

Annuals for Specific Locations

Most annuals will do well in Michigan if given the proper location and care. There are, however, certain annuals that may tend to do better in some locations than others. Proper plant selection can provide cool weather color, brighten a shady spot, dress up a hot dry location or accent an open sunny area.

Shady Location: Rare is the plant that will flower in heavy shade, but many do well with four hours or less of direct sunlight. Plants must often compete with trees and shrubs for moisture and nutrients. If the shade is due to structures, proper plant selection is important. Here are a few suggested plants for shade areas. For very heavy shade select impatiens, begonia, coleus, browallia, fuchsia and torenia. For light shade, lobelia, nicotiana, red salvia, pansy, alyssum, dusty miller, impatiens, begonia, ageratum, and dianthus are suggested.

strawflower

Sunny Location: Hot and dry areas are common along the edges of pavement or in front of light colored, south facing walls. Intense heat dries the ground quickly and tests the staying power of most annuals. Protect plants in these locations with a thick mulch and water thoroughly. Here are some plants that do well in hot dry areas: amaranthus, celosia, vinca, gazania, melampodium, ornamental pepper, blue salvia, zinnia, verbena, portulaca, dusty miller, petunia, and strawflower.

After Planting Care

Fertilization: Most annuals do not require high levels of fertilizer, and will do well with just the initial fertilization during soil preparation. However, any check in growth caused by insufficient nutrients can reduce the quality of the plant and its bloom, so its usually better to make an additional application during the growing season. About 6-8 weeks after planting, apply about one-quarter to one-half the recommended bed preparation rate of fertilizer to the planting bed. 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 suggested that they be applied to damp (not dry) soil.

nasurtium

Watering: Deep, infrequent watering is much preferred over frequent, light watering. The former encourages a deep root system. The amount and frequency will depend on natural rainfall and the type of annuals grown. The foliage should be kept dry to help prevent foliar diseases. When this is not possible, water early enough in the day so the foliage dries off before nightfall.

Mulching: After annuals are planted, it is suggested that a 2-3 inch layer of organic mulch be applied around the plants. Not only is it attractive, but it also helps conserve soil moisture, retard weed growth and keeps soils cool. Some good mulches to consider are compost, shredded leaves, dry grass clippings, bark chips, hulls, and pine needles. In the fall, the mulch can be incorporated into the soil adding organic matter and helping to improve soil structure.

Weeding: This is not the most fun activity, but it is essential to keep the weeds out and preventing competition for space and nutrients in the garden. Weeds should be removed as soon as you see them with shallow cultivation. When mulch is used and the canopy of the flowerbed grows closed, weeds should not be a major problem.

zinnia

Grooming: Many annuals require little additional care to keep them attractive and blooming all summer. Some flowers fall off cleanly and do not need to be manually removed. Others require “deadheading.” An annual lives in order to produce seed. All of its energies are directed toward this task. If you “deadhead” – pick the spent flowers before they start to set seed – the plant will produce more flowers in an effort to ultimately produce seeds. This practice keeps annuals in the flowering stage longer and usually results in a greater number of blooms. Annuals such as marigold, zinnias, salvia, geranium, cosmos and other spike or single stem flowers benefit from this practice.

In order to control the growth of some annuals, pinching or the removal of the growing tip is suggested. This will encourage more compact growth and a neater habit. The tops of some plants, such as petunia and impatiens, may be cut back 6-8 inches in mid to late summer after the first flush of flowers has subsided to promote a second flowering period in the fall. A good time to do this is right after the Fourth of July holiday. After cutting, fertilize and water well to encourage regrowth.