Perennials are plants that live year after year. Trees and shrubs are perennial. Most garden flowers are herbaceous perennials. This means the tops of the plants (the leaves, stems, and flowers) die back to the ground each fall with the first frost or freeze. The roots persist through the winter, and every spring new plant tops arise. Any plant that lives through the winter is said to be hardy. There are advantages to perennials, the most obvious being that they do not have to be set out every year like annuals. Some perennials, such as delphiniums, have to be replaced every few years. Another advantage is that with careful planning, a perennial flower bed will change colors as one type of plant finishes and another variety begins to bloom. Also, since perennials have a limited blooming period of about 2 to 3 weeks, deadheading, or removal of old blooms, is not as frequently necessary to keep them blooming. However, they do require pruning and maintenance to keep them attractive. Their relatively short bloom period is a disadvantage, but by combining early, mid-season, and late-blooming perennials, a continuous colorful show can be displayed Annual flowers live only for one growing season, during which they grow, flower, and produce seed, thereby completing their life cycle. Annuals must be set out or seeded every year since they don’t persist. Some varieties will self-sow, or naturally reseed themselves. This may be undesirable in many flowers because the parents of this seed are unknown and hybrid characteristics will be lost. Plants will scatter everywhere instead of growing in their designated spot. Examples are alyssum, petunias, and impatiens. Some perennials, which are plants that live from year to year, are classed with annuals because they are not winter-hardy and must be set out every year; begonias and snapdragons are examples.
Annuals have many positive features. They are versatile, sturdy, and relatively cheap. Plant breeders have produced many new and improved varieties. Annuals are easy to grow, produce instant color, and, most important, they bloom for most of the growing season. Many annuals are able to thrive without the need of grooming due to their “self-cleaning” ability.
“Bulbs” is a term loosely used to include corms, tubers, tuberous roots, and rhizomes as well as true bulbs. This publication will refer to all of the above as bulbs. Many vegetables are propagated from or produce edible organs of these types (e.g., tuber, Irish potato; tuberous root, sweet potato; rhizome, Jerusalem artichoke; bulb, onion).
Some Best Management Practices
Test the soil to learn pH and nutrients already present; then select plants that will grow in the conditions in the landscape
Determine soil drainage capacity before planting
Avoid planting invasive species; instead choose plants, especially native plants, that minimize maintenance and increase habitat
Group plants with similar needs (water, fertilizer, sun…) for easier maintenance
Use plants or mulch to conserve water, suppress weeds and prevent soil erosion
In times of low precipitation irrigate the plants deeply and infrequently at a rate of one inch per week Irrigate early in the morning, rather than late at night, to minimize evaporation losses and allow plants to dry off before evening
**For questions or problems contact the Help Desk, by phone: 703-792-7747; by email at: mastergardener@pwcgov.org .
References:
Perennials – Culture, Maintenance and Propagation VT Publication 426-203
Annuals – Culture and Maintenance VT Publication 426-200
Flowering Bulbs: Culture and Maintenance VT Publication 426-201