Perennials
Perennials in the garden is a must
What is a perennial?
Perennials are defined by herbaceous plants that continue to grow year after year. The top of the plant dies by the end of the season, but the root survives and produces a fresh top next year. Unlike annual plants, perennials will continue to thrive in the same place for many years. Unlike woody plants, like shrubs and trees, perennials are herbaceous.
Moving perennials
After 5-10 years some perennials will benefit from being parted and relocated. Some perennials need to be moved because they are too invasive. Some die out in the middle (for instance iris and Shasta Daisy). When they are parted they start a new life. Parting perennials is also a method of spreading the plant – for instance when groundcover is meant to cover a larger area.
Perennials that grow slowly will usually tolerate relocation, but are difficult to part (for instance globeflower). If perennials must be relocated it is always a good idea to improve the ground by digging and inserting compost in the plant hole. Other perennials (for instance peony, hellebore and bleeding heart) will not take kindly to relocation. Perennials with a deep root, or another root system which is difficult to divide, should be left in peace.
Peonies
Perennials with decorative leaves and flowers
The concept of perennials covers thousands of different garden plants. Some are cultivated primarily because of their spectacular flowers (for instance Fernleaf Yarrow), others have rather dull looking flowers, but very decorative leaves (for instance Hosta, European wild ginger, Orange candleflower, Bergenia).
Perennials are also picked because of their shape. Perennials can be tall and slender (for instance Hollyhock, Wolfsbane, Delphinium). They must be tied with string or supported a fence in order not to tilt. Perennials can be low and wide and as such suitable as groundcover (for instance Lady's Mantle, Spurges, Geranium). So-called solitary perennials are suitable to stand alone (for instance, Peony, Adam’s needle, Bear's breeches).
Bergenia
Perennials for sun or shadow
Perennials thrive in different growing conditions. Some like shadow or half-shadow (for instance European wild ginger, anemones, Columbine, Rodgerzia, Lungwort), while others must be planted in full sun (for instance Coneflower, Helenium flower). Perennials with big flowers in yellow or orange colours should often be placed in the sun. Perennials with large leaves, on the other hand, will usually benefit from a shady location.
Perennials for different soils
Some perennials are sturdy and easy to cultivate – they thrive in sun and shade and in many different kinds of soils (for instance Japanese anemones and Bergenia).
Some perennials thrive in calcareous soils or soils with high pH values, while others prefer highly acid soils with low pH values. There are also different preferences when it comes to sand and clay in the soil. A clay soil contains a lot of water, which some plants must have. A sandy or rocky soil is dry, but alpine or succulent plants are fine with that. Most perennials are not likely to thrive, however, in a sandy soil, if they do not get enough irrigation.
On the other hand it is important that the soil do not get too clayish or wet. There must be drainage, so the water can run away – otherwise the roots of the plant will be damaged. Some perennials, however, thrive in very moist soils, plants that are suitable at the edge of a pond or basin or some place deep in the garden where rainwater is collected (for instance Astilbes, Caltha, Meadowsweet, Trollius).
Japanese anemones
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