Some of the coolest trees on the planet can be found in Australia, and agonis flexuosa is no exception. Most commonly known as the peppermint tree, they are also sometimes referred to as the Western Australian Peppermint tree, the Swan river peppermint tree, or the Australian willow myrtle tree (because of its weeping habit). The aboriginal peoples of western Australia, the Noongar, refer to this tree as the Wanil, Wonnow, Wonong, or Wannang tree.
This tree is a very common specimen tree or street tree in Australia. Thanks to its attractive evergreen foliage (that smells like peppermint when crushed!) it makes for an excellent shade tree in one of the hottest places in the world. It is the most common of the agonis species.
The genus name, agonis, derives from the ancient green word, agon, which translates to “a cluster”, which is in reference to the growth habit of the fruit. The scientific term flexuosa is latin for “full of bends”, which is in reference to the odd growth pattern of the trees’ twigs.
Once you’re done learning about the peppermint tree and you realize “oh my goodness there are so much more trees than I ever could have imagined”, fear not! We have compiled a list of 101 Types of Trees and 50 Different Fruit Tree Flowers from all over the world, and written a detailed article for every single one!
What do Peppermint Trees Look Like?
It’s not secret that the Australian outback is a rugged place, and so it’s safe to guess that the native plants of these regions have developments in place to help weather that intense.. weather.
The peppermint tree will adapt its root system depending on the growing location of the tree. All trees will develop wide-spreading lateral roots. Though they grow outwards for quite a distance, they don’t grow too deep in the soil. These types of roots are common in flat, sandy areas, though an extra support system will develop if trees are growing on more rocky terrain.
This extra support comes in the form of buttress roots. Buttress roots are aerial extension of those surface level roots. These roots help stabilize trees that exist in shallow soils, and high wind regions. This is very common in tree species that exist in wet lowlands, which is common in Australia.
Peppermint trees are small trees, but they are robust! Though they usually only grow to be about 10 meters tall, there are some that can achieve heights of over 15 meters. Trunks are wide, usually about 1 meter in diameter.
The most identifiable aspect of the peppermint tree is its growth pattern. Their crown is a distinct vase shape, created by the trees’ pendulous branches and weeping habit. They are actually easily misidentified as weeping willow trees!
Some other noticeable aspects of this tree is the way that the twigs grow in a zig zag pattern, and the spiral or twist effect of the trunk that increases with age.
Peppermint trees have red/brown bark that is highly furrowed, and exfoliates in longitudinal strips.
Now, we learn about why this tree earned the common nickname, the peppermint tree, as this is not where the herb we use for teas and mojitos comes from.
Peppermint tree foliage is evergreen, meaning that it will persist and remain green all year long, regardless of the seasons. These leaves are very narrow, and about 150mm long. They are very similar to weeping willow tree leaves. A leaf is a dull dark green color, and when a leaf is crushed, it will emit a very distinguishable and strong odor of peppermint!
How do Peppermint Trees Reproduce?
Peppermint trees have perfect flowers, meaning that a single flower will possess both male sexual characteristics and female sexual characteristics.
Flowers are borne in tightly clustered (remember, agonis is green for clusters?) inflorescences of small white flowers. Flowers emerge between the months of August and December and are self-pollinating.
The fruit of the peppermint tree is borne as a hard capsule that is only 4mm across. Each capsule has 3 different valves that contain an enormous amount of seeds. Mammals and birds will eat and digest these capsules and disperses the seed through their scat.
Some peppermint trees will start to produce seed crops as early as 10 years old, though they will experience their most productive crop years between the ages of 20 and 30. Trees can live to be anywhere from 40 to 150 years old, though they will disperse millions of seeds in their lifetime.
Where does the Peppermint Tree Grow?
Peppermint trees are endemic to Australia, meaning that they have only ever been recorded existing there. They have a rather small growing zone, starting at the subcoastal strip of northern Perth, southward to the Swan river coastal plain.
They can exist in hardiness zones 9-11, and can be found growing right inland from the western Australian coastline in limestone heath, in sandy soils, and in stable sand dunes.
What are the Growing Conditions of the Peppermint Tree?
Peppermint trees prefer to exist in sandy soil, but they can tolerate both clay and loamy soil as well. Soil can be either wet or dry, either acidic or alkaline.
This type of soil is usually poor soil, meaning that it is low in nutrients, indicating that this tree is not in need of fertilizer if it lives in your garden.
These trees prefer to exist in full sun conditions, though they can tolerate partial shade.
The regions in which peppermint trees grow receive at least 32-40 inches of annual precipitation. They do not perform well in drought conditions.
Though these trees are able to tolerate extremely hot temperatures, they are completely intolerant of extremely cold temperatures.
How are Peppermint Trees Used?
The most common purpose of the peppermint tree is as an ornamental tree. They’re a popular garden tree, specimen tree, street tree, or shade tree. They’re valued because of their dense evergreen foliage with a lovely scent, weeping habit and wide covering crown.
The aboriginal population of Noongar peoples have traditionally used peppermint tree foliage as a natural antiseptic, and sapling trunks were used as spear shafts.