Annuals provide gardeners with an inexpensive way to add diversity and an array of long lasting colorful flowers to the landscape. Although they will flower all season long, annuals sprout from seed, produce flowers, set their seed and die within one growing season. Annuals need to be replanted each year, at least here in New England. What can be considered an annual in Massachusetts may actually be a perennial in Florida so the term annual is to some extent relative.
Annuals cannot tolerate freezing temperatures so they need to be planted in the spring after the there is longer a threat of frost; here in eastern MA it’s generally safe to plant in May. You should know your local environment before you plant as well as the requirements of the flowers. Few annuals will flourish in shady conditions and most prefer between 6 and 8 hours of sun per day, there are a few annuals, however, such as impatiens and begonias, which will tolerate some light shade. When choosing your site, avoid areas which remain water logged after summer showers.
With their impressive exhibit of colorful flowers, annuals can stand on their own as bedding plants. Annuals can also provide color to the herb garden or fill in thin spots and gaps in the perennial bed where they can compliment other flowers.
Appropriate site preparation is crucial. You'll want to supplement the existing soil with compost and other organic matter in order to enhance water retention in sandy soils. For clay soils, which often retain too much water, add compost and sand to improve drainage. To prepare the garden for planting till the soil to the depth of about 1' and add the appropriate amendments. Basically, you'll want to prepare the planting area the same way you would a perennial bed. When planting, add to the soil a slow release fertilizer so the plants are fed throughout the entire growing season. To promote deep root growth water thoroughly. Let the soil dry out before watering again, soil which is too wet will often result in root rot. Soaker hoses are great for annual beds since they slowly soak the soil while keeping the flowers and leaves dry. Nutrient rich soil will help annuals establish themselves quickly. This is especially important in regions which experience short growing seasons.
Once the annuals start to bloom deadheading the flowers becomes essential. This the process in which the spent flowers are pruned or pinched off of the plant. Deadheading prevents annuals from putting all of its energy into producing seed heads; rather, their energy will go into producing more flowers.
A light mulch, such as cocoa shells or buckwheat hulls, will help limit the sprouting of weeds in the garden. They'll also help the soil retain moisture. Be sure to remove any weeds that do appear since annuals do not like competition for water and nutrients. It is also possible for annuals to compete with other flowers like perennials or an adjacent lawn area. If the flowers are to be grown in a bed surrounded by lawn space, make sure that you edge the garden bed regularly with a garden spade. This will help keep the grass roots from growing beneath the garden and robbing the annuals of nutrients and water. Annual beds which are cut into the lawn should be at least 3 ft. wide; this will give the plants enough room to flourish. Cultivating the garden soil throughout the season will loosen compacted soil and allow moisture and nutrients to reach the plant’s deepest roots.
In the cooler climates of the north it is possible but not advisable to start annuals from seed outdoors in the garden. The season is just too short. You can, however, start them from seed indoors. Begin planting the seeds about three weeks before transplanting them into the gardens. This will give the annual time to get itself started.
When spring arrives, head out to the greenhouse, pick out some annuals and plant them as soon as the weather permits. Annuals tend to be a bit more labor intensive than perennials but the payoff, non stop colorful flowers from spring through autumn, makes it worth it.