What is a Perennial?
The term perennial is used to describe any plant, which lives for longer than two years quite often many years , which are not trees, shrubs (technically a shrub can be termed a perennial as it just means it will live for many years) or bulbs. So a perennial can have foliage which may be evergreen or die back in winter, within the term perennial you may also hear a plant described as anherbaceous perennial -Herbaceous perennials differ in that all the stems die back in late autumn and early winter. The roots then survive below ground during winter, laying dormant until shoots appear again in spring.
You may also hear a plant described asa short-lived perennial these may only live for a few years before needing to be replaced.
Many perennials can be raised from cuttings; softwood and semi-ripe. Others can be raised from seed. Perennials can usually be divided.
Growing Perennials from seed
Some Perennials can be raised from seed such as:
- Allium tuberosum (Garlic Chives)
- Allium nutans (Siberian chives, Blue flowering garlic chives)
To sow seed you can refer to the individual page for each of our plants for full instructions. As a as a rule of thumb:
Sow seeds at any time covering them lightly with compost or grit, keeping in a cool, well-lit spot. Artificial heat is not generally needed, grow on individual seedlings in small pots until of sufficient size to be potted on or planted out into the open ground.
Many species will only germinate in the spring after chilling or freezing in the moist seed tray in the winter ( A process known as Stratification) Such as Allium nutans (Siberian chives, Blue flowering garlic chives). Plant up your seed trays as above in early autumn cover with glass to keep pests from eating or disturbing the seed and place outdoors overwinter, germination should then take place in the spring.
Staking: many tall perennials will need staking to hold the flowers upright and prevent flopping.
Pruning :Perennials need little pruning. Always cut off dead diseased or damaged pieces of plant. However, there are two other instances where it is can be done or is needed
Cutting back - In the case of herbaceous plants which die back in autumn the dead stems should be cut off at ground level either in autumn or late winter.
Chelsea chop - Plants which can grow very leggy can be reduced in height completely to produce a stockier plant - or a third or more can be cut to allow for a prolonged flowering period if this is the desired result.