Perennials bring us their annual share of flowers before drying out to face the winter. These plants grow everywhere, and adapt to any soil type. Thanks to annual regrowth, they enjoy a natural rejuvenation. Several species of perennial plants are now available in garden centres. Planted in the right location with suitable soil and adequate light, they are very easy to maintain and produce the best blooms.

Depending on the season, there exist many perennials that can be planted along borders, in gardens, on terraces or to embellish a rockery. In spring, it is forget-me-nots, lily of the valley, iris, shrubby or herbaceous peony and valeriana that will brighten up your garden; in summer, that task will be handled by bellflowers, sages, oxeye daisies and carnations. However, in winter the setting’s colours will be provided by sweet violets, adonis, primroses or hellebores and in autumn, by Japanese anemone, stonecrops and helianthus. With their colourful blooms and lush development, perennials are the gardeners’ delight. Here are some tips on cultural methods and maintenance techniques relative to these plants which come back every year.

Overview and characteristics

Compared to annuals and biennials, the term “perennial” refers to plants that can live for more than two years. This definition does not apply to “ligneous” plants such as trees and shrubs. Most perennials have the distinctive traits of losing all or a portion of their aerial parts and drying out during the bad season. Only the underground stump will survive, and will resume growth as soon as outside weather conditions become milder. Perennials include many species of varied plants. Besides the general characteristics that apply to most of them, consult a horticulture specialist to identify each variety’s specific needs in order to provide them with the most appropriate care.

Growing and maintaining perennials

Perennials are available in containers in garden centres. This is what makes their planting possible year-round, except during periods of exceptional frost or drought. Even so, two periods are recommended for planting. Planting in early fall is recommended for spring flowering plants. Young plants thus have enough time to settle before the winter. This planting period is also recommended for regions with hasty and dry springs. If the winter is not particularly harsh, planting in the fall or just at the end of winter allows the plants to adapt before the arrival of hot summer heat. Spring planting is also recommended for areas that have cold and humid winters. This is the only way to guarantee the plant’s immediate start. This time period is also suitable for heavy soils that do not drain well.

The perennials’ preferences in terms of soil types differ from one species to another. If you need to amend the ground, do not use fresh manure in the planting holes. The use of compost is ideal. Low-nitrogen fertilizer is the most suitable kind for perennials, which need phosphorus and potassium for better growth and flowering. A moderate but regular watering is essential especially during the summer. Mulching is also effective to keep the soil’s humidity level constant and to reduce the watering frequency. It also helps curb the proliferation of weeds. However, it does not eliminate the need for hoeing, which cleans plots of land and airs out the ground. Staking is sometimes necessary to sustain plants weakened by outdoors conditions (heavy rain, wind gusts …). Staking and training can also be systematically applied to perennials to give them a particular shape. Special supports are available in garden centres, and can provide gardens with an original touch.

Depending on species, perennials can be pruned in autumn and early spring. Most of the time, pruning consists of lopping stems that have flowered and which will dry up at the season’s end. Used at the right time, lopping may also be carried out to give the plant a second breath and induce a second flowering. Disbudding is more frequently used to give strength to the strain. It involves cutting the top of the shoots to slow their development. Disbudding causes further branching of the plant, but can also induce a lag in flowering. It is important to prepare perennials for winter. This can be done by mulching the plants’ base with a layer of dry leaves, which can itself be covered by a plastic sheet or turned-over pot. For the most fragile species, setting up a cold frame may be necessary.

Perennials’ diseases and pests

If each species has its specific parasites, the perennial plants’ most common pests are snails and aphids. Snails and slugs mainly attack young shoots in the spring. Efficient baits against these pests are available in garden centres. The use of insecticides is not advisable because they prevent the arrival of pollinators such as bees and butterflies. On the other hand, companion planting is recommended with aphid-repellent plants such as French marigold. The most feared diseases are powdery mildew and rust. Applying fungicidal treatment is often necessary in the case of attacks. Preferably resort to a non-chemical treatment. To prevent the attack from spreading and affecting all species, it is recommended to get rid early of the plants’ diseased parts.

No related posts.

Published in Flower guide by Alexander on 06 Jul 2011