Agonis
( ag - OH - niss )
At-A-Glance Information
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Agonis, also called Myrtle or Peppermint Tree, is an evergreen genus of one tree and various shrubs that require full sun to partial shade and little to regular water. Native to western Australia and related to Leptospermum and Melaleuca, these plants are not picky about soil or water, and are relatively easy to grow and maintain. Foliage color can vary from beautiful dark greens to lighter greens and purples. Although flowers are small, they bloom profusely on spikes and can really put on a great show in springtime. These trees are particularly handy in coastal areas where there are strong winds and are useful screening plants.
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Agonis Species and Varietals
The genus Agonis includes five species and is member of the plant family Myrtaceae. These shrubs and trees grow best in zones 15-17 and 20-24. See the species descriptions below for more information. To find your zone, click here: Zone Map.
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Agonis baxteri Named for the collector of the original specimen, William Baxter, this species forms an erect, sometimes bushy shrub that reaches up to 7 feet tall at maturity. Foliage is dark green and flowers are white, blooming from October through December in their native range. |
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Agonis flexuosa (Peppermint Tree, Australian Willow Myrtle, Swan River Peppermint, Wanil, Wonong) This species is a great small tree for many western gardens. Freezes to the ground at 25 degrees Fahrenheit, but can come back if the stump is protected and does not get more cold-damaged. This plant has a spreading growth and grows moderately quickly to 25-35 feet tall and 15-25 feet wide. Leaves are willow-like and smell like peppermint when crushed. Small white flowers bloom profusely in springtime. It can be a lawn tree, a patio specimen in a container, or an espalier on the side of a building. Popular varieties are outlined below: |
'Jervis Bay Afterdark'
Slow grower to 18 feet tall and 10-15 feet wide with gorgeous burgundy foliage. |
'Jedda's Dream'
Burgundy foliage, gets to 9 feet tall and 6 feet wide. |
'Nana'
Gets to 3-4 feet tall and twice as wide. New leaves are bright red. |
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Agonis thieformis (Summer Snowflakes) This shrub is native to western Australia and reaches between 2 and 7 feet tall at maturity. Flowers are white, and bloom December through October in the plants' native range. This is an ideal hedging, drought-tolerant plant choice and responds well to pruning. Foliage is a bit smaller and more rounded than that of other species in the genus. |
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Caring for and pruning agonis Trees
Plant your Agonis tree or shrub in full sun to partial shade; these plants should receive at least 6 hours of sun each day for optimal growth and health. It is critical to have well-draining soil for these plants; they also prefer soil to be acidic to neutral with a pH of between 6.0 and 8.0. Before planting, amend soil with plenty of organic material to improve tilth and drainage. Water regularly during the establishment period. At maturity, these trees and shrubs are considered to be drought-tolerant and will only need deep irrigations when the soil has completely dried out. Apply a layer of mulch around the base of the tree or shrub (taking care to ensure that the mulch does not come up too close to the trunk) to increase soil moisture retention, mediate soil temperature fluctuations, and to suppress weed growth.
Prune to shape and to remove dead, damaged, or diseased wood. Regular pruning can help these trees and shrubs maintain a compact, neat, attractive form. The best time to prune Agonis is in the late winter or early springtime, before new growth has had a chance to push out. Over winter months, if you live in a particularly cool area, these plants may need some protection from frost (especially when they are young or transitioning to a new environment). Fertilizing is not necessary; applications of organic matter can suffice. If an Agonis is having issues with particularly poor soil, it may be beneficial to apply a balanced, slow-release fertilizer around the base of the plant. Take care not to over-fertilize, as this can seriously damage Peppermint Willow trees and shrubs and lead to leggy growth.
Prune to shape and to remove dead, damaged, or diseased wood. Regular pruning can help these trees and shrubs maintain a compact, neat, attractive form. The best time to prune Agonis is in the late winter or early springtime, before new growth has had a chance to push out. Over winter months, if you live in a particularly cool area, these plants may need some protection from frost (especially when they are young or transitioning to a new environment). Fertilizing is not necessary; applications of organic matter can suffice. If an Agonis is having issues with particularly poor soil, it may be beneficial to apply a balanced, slow-release fertilizer around the base of the plant. Take care not to over-fertilize, as this can seriously damage Peppermint Willow trees and shrubs and lead to leggy growth.
Propagation
Agonis can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your tree or shrub, follow the instructions below:
Propagating Agonis by Cutting
Propagating Agonis by Seed
Propagating Agonis by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.
Propagating Agonis by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
- Harvest your seeds. The seed pods are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
- Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Agonis flowers fade to reveal round seed pods.
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Agonis seeds still on the branches of a tree.
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Problems and Pests
Although Agonis shrubs and trees are generally pest-free and disease-resistant, they can have issues with the following common garden pests from time to time:
- Spider Mites
- Aphids
- Scale Insects
Gallery
Dwarf varieties of Agonis are wonderful additions to mixed beds.
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The foliage of these trees and shrubs contrasts nicely with other foliage types.
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When grown as a tree, these plants have beautiful canopies and provide a good amount of shade.
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Agonis foliage is commonly used in cut flower arrangements.
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Agonis species with dark foliage are eye-catching additions to any landscape.
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Agonis trees make great screening plants, and look wonderful planted in groups.
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Videos
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Learn all about Agonis flexuosa trees and shrubs.
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All about Agonis 'After Dark'.
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Using Agonis greenery in flower arrangements.
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Learn about Peppermint Tree.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 140, Agonis
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