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Different types of plants have different lifespans – some live fast and die young, while others take years to reach their prime:

Annual plants grow, produce seeds and die in one year. However carefully you look after an annual plant, like this cosmos, it will never live longer than that.

Biennial plants live for two growing seasons, usually overwintering as leafy rosettes before flowering and producing seeds in their second year. Foxgloves (Digitalis) are a common example.

Herbaceous and woody perennial plants are potentially much longer lived – from a few years to many decades or more. They store resources, like starch, to survive adverse conditions and can replace damaged parts thanks to zones of cell division (meristems) in their roots and shoots. Perennial phlox is a popular choice for borders.

Knowing the life expectancy of our plants helps us to use and grow them successfully:

• The short lifespan of annual plants
  Annuals are plants that complete their life cycle in one growing season. They are generally easy to grow from seed or can be bought as young plants from garden centres. Annuals are ideal for growing in summer containers and filling gaps in borders. Some examples of annuals include sunflowers, cosmos, sweet peas and zinnia. makes them ideal for filling gaps in borders - providing colour and interest while you wait for your permanent plants to fill out
• Annuals
  Annuals are plants that complete their life cycle in one growing season. They are generally easy to grow from seed or can be bought as young plants from garden centres. Annuals are ideal for growing in summer containers and filling gaps in borders. Some examples of annuals include sunflowers, cosmos, sweet peas and zinnia. tend to produce lots of easily grown seeds – so it’s often worth collecting and storing their seed s rather than buying new each year
• Biennials
  Biennials are plants that complete their life cycle over the course of two years. In the first year, biennials typically produce leaves and roots but no flowers. In the second year, they flower and produce seeds before dying. Some common biennials include foxgloves (Digitalis), honesty (Lunaria annua) and viper's bugloss (Echium vulgare). can be easily mistaken for weeds in their first year, so use plant labels to identify them
• Sowing biennials every year for a few years (successionally), and allowing them to self-seed, can produce a reliable, yearly display
• Perennials are good for long-term plantings, but need space to grow into
• As perennials
  Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs. will grow in the same place for many years, they need extra care – this might include soil improvement, feeding, pruning and winter protection. See our guide to growing perennial plants

Plants have a juvenile and an adult stage. The time it takes to reach maturity differs between species.

• Juvenility is usually characterised by vigorous, soft and leafy, non-flowering growth
• Maturity is when growth is capable of flowering

Physical differences between juvenility and maturity is clearly seen in some plants. In ivy, for example, young, non-flowering stems cling and climb, while mature plants develop a shrubby, branching habit and bear nectar-rich flowers.

Grafting gets around juvenility by enabling a plant to flower sooner. It's useful in slow-to-flower plants such as magnolias. If a piece of mature magnolia stem is grafted onto a younger plant (rootstock), the grafted plant blooms years earlier than if the rootstock flowered itself.

Sometimes we don’t want plants to reach maturity and flower. Leafy salads, such as lettuce and coriander, can lose flavour once they start flowering (known as bolting). Keep them productive by regularly picking their leaves to extend their juvenility.

In many plants, flowering and leaf colour can decline with age. Choosing the right pruning regime can help avoid this, and revive plants that have become lacklustre:

• Pruning annually - to thin older stems or cut out flowered growth - encourages new replacement shoots and maintains a good balance of old and new wood. This helps to ensure plants produce plenty of flowers each year. Shrubs that benefit from annual pruning include shrub roses and mock orange ( Philadelphus ).
• Renovation pruning is a more severe option, for older, poorly performing shrubs, to improve their flowering or fruiting. Hard pruning triggers the production of hormones
  Chemical substances that regulate plant growth and development. There are several types of plant hormones, including auxins, cytokinins, gibberellins, abscisic acid and ethylene. These hormones play important roles in processes such as cell division, elongation and differentiation, as well as in responses to environmental stimuli such as light and gravity. that encourage dormant
  Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth. buds
  A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers. to sprout into growth. Always check if your shrub is known to respond well to this kind of treatment or whether replacing it would be a better option. See our guide to shrub renovation .
• Pollarding and coppicing plants such as eucalyptus , willow and shrubby dogwood (Cornus) encourages lots of new, colourful stems and foliage for a more vibrant display. See our guide to pollarding and coppicing .

Sometimes, when a plant is hard pruned, it responds by putting on lots of young leafy growth. This softwood doesn't have any stored resources (such as starch) so can take a long time to flower again. Apples respond to hard pruning by producing lots of vigorous upright stems known as watershoots. These require careful management so you don't encourage even more – for advice on this see our guide to renovating apple trees .

Some plant hormones

Chemical substances that regulate plant growth and development. There are several types of plant hormones, including auxins, cytokinins, gibberellins, abscisic acid and ethylene. These hormones play important roles in processes such as cell division, elongation and differentiation, as well as in responses to environmental stimuli such as light and gravity. (also known as growth regulators) promote ageing (senescence) and others counteract it:

• Hormones that maintain the function and structural integrity of cells, preventing tissues from dying, include auxins
  Auxin is a plant hormone that plays a role in regulating plant growth and development, particularly in cell elongation, root formation and apical dominance (where the main stem is dominant over other side stems). It is also involved in many other processes, including phototropism (the bending of plants towards light), gravitropism (the response of plants to gravity) and the development of fruit and flowers. , gibberellin
  Gibberellins are a group of plant hormones that play a role in regulating plant growth and development, particularly in stem elongation, seed germination and flowering. They are also involved in the production of chlorophyll and the regulation of fruit development. and cytokinin
  A group of plant hormones that play a role in regulating plant growth and development, particularly in cell division, shoot and root growth and the delay of senescence (ageing) in plants. They are also involved in many other processes, including the regulation of nutrient uptake and the response of plants to environmental stress.
• Hormones that promote ageing are ethylene
  Ethylene is a plant hormone that plays a role in regulating plant growth and development, particularly in response to environmental cues such as light, temperature and stress. It is involved in many processes, including fruit ripening, leaf senescence (ageing) and flower and seed development. Ethylene is also produced by plants in response to mechanical damage or pathogen attack and can act as a signal to nearby plants to prepare for potential threats. and abscisic acid
  Abscisic acid (ABA) is a plant hormone that plays a role in regulating plant growth and development, particularly in response to environmental stresses such as drought, cold and salt. It helps plants to conserve water by closing stomata (pores on the leaves) and reducing transpiration. ABA also plays a role in seed dormancy and germination, as well as in the regulation of flowering and fruit ripening.

Seasonal and environmental cues, such as daylength shortening, trigger biochemical shifts inside plants, tipping the balance in favour of the ageing hormones:

The lower temperatures and shorter days of autumn trigger leaf drop in deciduous trees and shrubs. Before falling, ageing leaves stop producing chlorophyll and their useful substances, like starch, are moved into stems for storage. Then, as auxin production is reduced and ethylene production increased, a layer of corky cells forms at the base of the leaf stem (petiole) and abscission (or separation) occurs.

Some tree species, such as beech, don't form an abscission zone when they're young. The dead leaves hang on, protecting new buds from cold. If you clip an established beech hedge in summer, the flush of new shoots it encourages will also keep its leaves, creating winter interest.

As fruits mature they produce more ethylene, which causes colour changes, an increase in sweetness and a softening of tissues. In apples, ethylene not only stimulates ripe fruits to fall, it also plays a role in shedding excess fruitlets in early summer (known as 'June drop').

Now you know more about how plants age, put this into practice to help your plants thrive:

• Consider the lifespan of the plants you're buying when you come to add more to your garden. Annuals
  Annuals are plants that complete their life cycle in one growing season. They are generally easy to grow from seed or can be bought as young plants from garden centres. Annuals are ideal for growing in summer containers and filling gaps in borders. Some examples of annuals include sunflowers, cosmos, sweet peas and zinnia. are a great shot of colour in a border, but need replacing every year. Perennials
  Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs. will be with you for longer, so are a more sustainable and economical option. See our guide to choosing perennials .
• Regularly pick the leaves of leafy salads to keep them productive and stop them bolting
• Check whether your shrubs would benefit from annual pruning to encourage fresh stems every year, for improved overall flowering. See our catalogue of pruning guides or consult a good plant pruning book such as
• Clip beech hedges in late summer so they hold their leaves over winter. This provides better screening, more shelter for garden wildlife and a colourful backdrop for your other plants. See our guide to growing beech
• Ripen green tomatoes at the end of the summer by putting them in a bowl with some already ripe tomatoes or a banana. The ethylene
  Ethylene is a plant hormone that plays a role in regulating plant growth and development, particularly in response to environmental cues such as light, temperature and stress. It is involved in many processes, including fruit ripening, leaf senescence (ageing) and flower and seed development. Ethylene is also produced by plants in response to mechanical damage or pathogen attack and can act as a signal to nearby plants to prepare for potential threats. given off by the mature fruit will encourage the green ones to sweeten and colour up. See our guide to growing tomatoes