The Difference Between Annual, Biennial and Perennial Plants
Decode the lingo with our jargon buster
By Daniel Woodley at DIY Gardening
If you’re looking for a concise explanation of the difference between perennials, biennials and annuals then this is the page for you. Other words are also explained.
Annual plants live for one growing season where they germinate, grow, flower, set seed and die, all within a year.
The roots of annual plants do not survive into a second year.
Annual plants are often used in hanging baskets, containers and borders where they produce an abundance of flowers for protracted periods, usually much longer than other types of plants.
Popular annuals are; pansies, petunias, pelargoniums (tender geraniums), begonias and busy lizzies.
Biennials are similar to annuals except that they live for two years.
In the first year, they grow leaves but rarely flowers. In the second year, they flower and set seed before dying.
Perennials are plants that live for more than two years.
Some will last for decades and these are known as hardy perennials while others only live for a few years, these are known as short-lived perennials.
“Tender perennials” live for more than two years but can’t survive frosts and must be relocated to a protected area for the winter.
Because perennial plants divert some of their energy into root development, they may not flower for as long as annual plants which pack more of a punch, but only for one season.
Examples of perennials are lavender, dianthus and hardy geraniums.
“Herbaceous Perennial” Meaning
Herbaceous perennials are plants that live for more than two years, but each year, their top growth dies back to the roots, and new growth appears the following season.
This type of perennial typically has soft stems that can’t survive the winter, but it will grow again from the ground in the spring.
Examples of herbaceous perennials are rudbeckias, echinacea and sedums.
Hardy plants are those that can survive certain weather conditions and temperatures.
Most commonly used to describe plants that can survive winter, it also includes those that tolerate drought, heat and flooding etc.
Some plants are hardy in certain parts of the country, such as the south but aren’t as hardy in the colder north.
“Half Hardy” Meaning
Half hardy plants are hardy in mild weather conditions but will not survive more extreme weather such as frosts.
Gradually acclimatising a plant to outside weather conditions and temperatures. This usually involves moving a plant previously grown indoors to an outdoor location, first during the day and then leaving it outside permanently after a week or so.
A plant that retains its leaves throughout the year.
Plants that lose their leaves each year, often in autumn and winter.
Plants that lose their leaves for a very short period or plants that only lose some of their leaves.
Tubers are planted in the ground where they grow roots and sprout stems. The potato and dahlia are the most well-known plants grown from tubers.
Plants grown from tubers die back each year and, provided the tubers isn’t damaged by frost, will grow again the following year.
Tubers spread by multiplying and splitting and are asexual.
To grow new plants from cuttings taken from a donor plant.
Trimming back plant stems for aesthetic purposes or to encourage new growth.
Some plants will stop producing flowers when seeds are set (created) and seeds are always set in the flower head.
To prevent a plant from setting seed, one can cut off the old flower heads, a process known as deadheading.
Deadheading is a very good way to encourage more numerous and larger blooms in some plants.