The eucalyptus plant (Eucalyptus cinerea) is an iconic evergreen, widely recognized as a favorite of the koala. Known for its fast growth and distinctive menthol fragrance, it’s a popular choice among gardeners worldwide. Originally from Australia, this resilient plant is now cultivated globally, including in home gardens. While it can grow up to 60 feet in its natural habitat, eucalyptus is often pruned to a manageable size for household landscapes, usually between 6 to 10 feet tall.
This guide explores the essential aspects of growing eucalyptus, from ideal conditions to maintenance tips.
Basic Characteristics of Eucalyptus
Eucalyptus has silvery-blue leaves, releasing a calming scent when bruised, and reddish-brown bark that peels beautifully from the smaller branches. As an evergreen, eucalyptus provides a year-round appeal. It’s crucial to note, however, that eucalyptus trees are toxic to both humans and pets, so they should be planted thoughtfully.
- Common Names: Eucalyptus, Silver Dollar Tree, Argyle Apple
- Botanical Name: Eucalyptus cinerea
- Family: Myrtaceae
- Mature Size: 6–53 feet tall, 2–15 feet wide
- Sun Exposure: Full sun
- Soil Type: Well-drained
- Soil pH: Acidic to neutral
- Bloom Time: Summer
- Flower Color: White, red
- USDA Hardiness Zones: 8–11
- Native Area: Australia
- Toxicity: Toxic to humans and pets
How to Plant Eucalyptus
Eucalyptus plants are best planted in the spring to give them time to establish before the cooler months. These trees are low-maintenance once settled, requiring minimal staking due to their natural resilience. Their rapid growth rate means they can gain several feet annually, making them an ideal choice for gardeners looking for quick results.
Light Requirements
Eucalyptus plants are sun-loving evergreens that thrive with full sun exposure. To ensure healthy growth and vibrant foliage, choose a location that receives at least six hours of direct sunlight each day. This level of light is crucial, as eucalyptus needs intense sunlight to support its rapid growth and to maintain its beautiful blue-green leaves and distinct fragrance. Without sufficient sunlight, the plant may become leggy, lose its color vibrancy, and have slower growth.
For indoor eucalyptus plants, place them near a large, sunny window to mimic the bright conditions they’d experience outdoors. A south-facing window is ideal, as it captures maximum sunlight throughout the day. Make sure to rotate the pot occasionally to promote even growth on all sides of the plant.
If natural light is limited, consider supplementing with grow lights to provide the intensity needed, especially during winter months when daylight is shorter. Remember, insufficient light may weaken the plant, making it more susceptible to pests and diseases. Proper light management is a key element for a healthy, flourishing eucalyptus.
Soil Preferences
Eucalyptus plants are adaptable but thrive best in well-drained soil. Proper drainage is essential to prevent root rot, as eucalyptus roots are particularly sensitive to overly moist or waterlogged conditions. For garden planting, choose soil that’s sandy or loamy, as these types naturally provide good drainage while retaining enough moisture for healthy growth. Amending heavy clay soil with sand or organic matter can help improve drainage and aeration, creating a more suitable environment for eucalyptus roots.
For container-grown eucalyptus, it’s vital to select a high-quality potting mix specifically formulated for fast drainage, like a cactus or succulent blend. You may add perlite or coarse sand to enhance drainage further. Additionally, ensure the pot has sufficient drainage holes to allow excess water to escape.
Eucalyptus plants perform best in soil with a slightly acidic to neutral pH, ideally around 5.5 to 7.0. A pH testing kit is an easy tool to check your soil’s acidity level; adjustments can be made by adding lime to raise pH or sulfur to lower it, if necessary. This pH range supports nutrient absorption, helping the eucalyptus thrive and resist common plant diseases.
Watering Needs
Eucalyptus plants are naturally drought-tolerant once established, making them a great choice for low-maintenance gardens. However, while they can endure dry spells, they do not thrive in prolonged dryness. A regular weekly watering schedule works well, especially in periods with little or no rain. Monitoring soil moisture is key to providing the right amount of water. A simple way to check is by sticking your finger about an inch into the soil. If it feels dry at your fingertip, it’s time to water.
For container-grown eucalyptus, be mindful that potted plants dry out faster than those in the ground, as containers hold less soil and are more exposed to air. As a result, container eucalyptus may require more frequent watering—sometimes even twice a week in hot, dry conditions. However, always ensure that the soil is moist but not waterlogged, as eucalyptus roots are prone to root rot if kept too wet.
During hot summer months, you may need to adjust the watering frequency to keep the soil from drying out completely.
Temperature and Humidity
Eucalyptus plants thrive in warm temperatures ranging from 65 to 75°F (18–24°C), which closely mimic their native Australian climate. These warm conditions support their fast growth and vibrant foliage. Eucalyptus plants also prefer moderate humidity levels, making them well-suited for outdoor gardens in warm, mild climates or indoors near a humidifier if the air is particularly dry.
One important consideration is that eucalyptus cannot tolerate prolonged exposure to temperatures below 50°F (10°C). Cold weather can lead to leaf drop and weakened plant health, especially if temperatures drop to freezing. For regions with cold winters, gardeners growing eucalyptus in containers should bring them indoors once temperatures approach this threshold. Place the plant near a bright, south-facing window indoors where it can still receive ample sunlight. While indoors, avoid placing eucalyptus near heating vents or drafty areas, as extreme fluctuations in temperature can stress the plant.
If bringing a potted eucalyptus indoors isn’t an option, consider covering outdoor plants with frost protection cloths during brief cold spells.
Fertilizer Requirements
Eucalyptus plants grown directly in the ground are generally low-maintenance when it comes to fertilizing. In most cases, they do not require any additional nutrients, as they can obtain what they need from the soil. However, container-grown eucalyptus has different needs. Due to the limited soil volume and faster nutrient depletion in containers, these plants benefit from a light feeding during the growing season to support healthy growth and foliage.
When fertilizing potted eucalyptus, choose a low-nitrogen fertilizer to prevent overly rapid growth that can stress the plant. A balanced, water-soluble fertilizer diluted to half strength is ideal, as too much nitrogen can cause weak, leggy growth rather than the desired strong, compact structure. Apply the fertilizer every 4–6 weeks during the spring and summer months, following the instructions on the product label.
Always avoid over-fertilizing eucalyptus, as this can lead to nutrient imbalances and potential root burn. During the fall and winter, reduce or halt feeding altogether, as eucalyptus naturally slows its growth in cooler weather.
Types of Eucalyptus
Eucalyptus offers a diverse range of species, each with unique characteristics that make them favorites among gardeners. Here are three popular varieties:
Eucalyptus globulus (Blue Gum)
Known as Blue Gum, this species is highly adaptable to various environments. It features smooth, aromatic bark that peels away in ribbons, adding visual interest. Its blue-green leaves release a refreshing fragrance when crushed, making it popular in gardens and landscapes. Eucalyptus globulus is also commonly used in essential oil production due to its high eucalyptus oil content.
Eucalyptus gunnii (Cider Gum)
Cider Gum is prized for its cold tolerance, making it suitable for regions with milder winters. Its rounded juvenile leaves mature to a stunning silvery-blue, creating a striking display. This eucalyptus variety grows into a bushy tree and is relatively compact, making it easier to manage in small spaces. It’s a top choice for gardeners in temperate climates looking for a hardy, visually appealing eucalyptus species.
Eucalyptus platypus (Moort)
Known for its hardiness, Moort can withstand colder climates and drought conditions, making it resilient in challenging environments. Eucalyptus platypus has dense foliage and a compact form, which suits urban gardens and smaller landscapes. Its rounded, glossy leaves add a lush appearance, and it’s often chosen for its low maintenance needs.
Pruning and Maintenance
Pruning eucalyptus trees is typically a low-maintenance task, as these trees naturally develop an attractive shape. However, occasional pruning can be beneficial for maintaining a balanced and healthy form. The main reasons for pruning include removing broken, damaged, or diseased branches and controlling the size and shape of the tree, especially in smaller gardens or landscape designs where a more compact tree is desired.
The best time to prune eucalyptus is during the summer, when the tree is actively growing and the cut wounds can heal quickly. Pruning during dry conditions also helps reduce the risk of fungal infections and diseases, which can occur if pruning cuts are exposed to high humidity. It’s important to avoid pruning during very humid or wet weather, as this can increase the likelihood of disease spreading within the tree.
When pruning, try to limit cuts to only the branches that need shaping or removal. Excessive trimming can stress the eucalyptus, especially in warmer climates where the plant might struggle to recover if too much foliage is lost. For young eucalyptus trees, light pruning encourages strong, balanced growth, while mature trees generally require less pruning.
Propagating Eucalyptus
Eucalyptus is typically grown from purchased seeds or nursery plants. However, propagation from cuttings is a cost-effective alternative, although success rates may vary. The ideal time for propagation is in late summer.
Steps to propagate eucalyptus from cuttings:
- Prepare a Growing Medium: Use a mixture of three parts composted bark and one part perlite, adding slow-release fertilizer.
- Select a Cutting: Choose a healthy 5-inch stem with four to eight leaves, trimming just above a leaf node.
- Prepare and Plant the Cutting: Remove lower leaves, dip the cut end in rooting hormone, and plant in the potting medium.
- Provide Optimal Conditions: Place the pot in bright, indirect light and keep the soil moist. Roots should appear in around a month.
Growing Eucalyptus from Seed
Growing eucalyptus from seed requires some preparation. Seeds must be chilled in a refrigerator for about two months before planting to mimic winter dormancy. Start them indoors 10 to 12 weeks before the last frost for your area.
Steps for germinating eucalyptus seeds:
- Sow Seeds: Lightly cover the seeds in a seed-starting mix.
- Provide Warm, Indirect Light: Place the pots in a warm area with indirect light, misting the soil to keep it moist.
- Transplant: Once seedlings reach around 6 inches tall, they can be planted outdoors in suitable conditions.
Potting and Repotting
Growing eucalyptus in containers is a practical solution, especially in regions where outdoor planting is limited by colder climates. Container-grown eucalyptus allows gardeners to enjoy these beautiful plants without worrying about freezing temperatures. Due to their fast growth rate, many gardeners treat potted eucalyptus as annuals, replanting each season to keep them compact and manageable.
When potting a eucalyptus, choose a 5-gallon pot to provide ample space for root development while avoiding frequent repotting. An unglazed clay pot is ideal, as its porous nature allows moisture to escape through the walls, preventing root rot by reducing the chances of waterlogging. It’s essential to ensure the pot has multiple drainage holes to facilitate proper water drainage.
For the potting medium, use a well-draining soil mix such as cactus or succulent soil. Adding perlite or coarse sand can further enhance drainage, an essential factor for eucalyptus, which dislikes soggy conditions. Avoid using garden soil, which may compact and retain too much moisture in containers.
As eucalyptus grows, repotting may become necessary to refresh the soil and support continued growth. However, to avoid disturbing the roots, choose a slightly larger pot if repotting and avoid doing so more than once a year.
Overwintering Eucalyptus
For those growing eucalyptus in containers outside its hardiness zones (typically USDA zones 8–11), it’s crucial to bring these plants indoors during the winter to protect them from cold weather. Eucalyptus is not frost-tolerant; exposure to freezing temperatures can cause severe damage to the foliage and may even kill the plant. Proper overwintering ensures your eucalyptus remains healthy and ready to thrive again when warmer temperatures return.
When moving your eucalyptus indoors, place it near a bright, south-facing window to provide as much natural light as possible. Eucalyptus needs consistent light, even in winter, to maintain its vibrant foliage. If natural light is limited, consider supplementing with a grow light to keep the plant in optimal health.
During winter dormancy, slightly reduce watering to prevent waterlogged soil, but don’t let it dry out completely. Eucalyptus in dormancy does not require fertilizer, as this could stimulate unwanted growth. Avoid placing the plant near heating vents or drafty areas, as eucalyptus is sensitive to sudden temperature changes.
If bringing the plant indoors is not an option, use frost protection methods, such as covering it with horticultural fleece or frost blankets during cold nights.
Harvesting Eucalyptus Leaves
The ideal time to harvest eucalyptus leaves is late in the growing season when the leaves are mature and full of essential oils. This timing ensures that you’re collecting leaves at their peak quality, which can be used for various purposes, including home decor and aromatic projects. To begin harvesting, use clean pruning shears or sharp scissors to snip off the desired leaves from the stems, taking care not to damage the plant.
After cutting, the next step is to air-dry the leaves. Place them in a single layer on a drying screen or a clean, dry surface, away from direct sunlight. It’s important to avoid sunlight during the drying process, as excessive heat can degrade the aromatic oils and vibrant color of the leaves. Ensure good air circulation around the leaves to facilitate even drying, which typically takes a few days.
Once the leaves are completely dry—characterized by a slightly leathery texture—they can be stored for future use. Place the dried leaves in sealed jars or airtight containers to protect them from moisture and preserve their fragrance. Properly stored, dried eucalyptus leaves can last for months and can be used in floral arrangements, potpourri, or to infuse oils for aromatic therapies.
Common Pests and Diseases
Eucalyptus plants are generally resilient; however, they can occasionally face challenges from common pests and diseases. One notable pest is the long-horned borer, which can infest stressed eucalyptus trees. Signs of this infestation include oozing sap and discoloration of the leaves, indicating that the plant is under stress.
In addition to pests, eucalyptus can be susceptible to fungal diseases. Gardeners should regularly inspect leaves for black or brown spots, especially on the underside, which are indicative of fungal infections. These issues are often exacerbated by high humidity and poor air circulation.
Fortunately, maintaining proper care, including adequate watering and sunlight, can bolster the plant’s defenses against these threats. Regular pruning to remove infected or damaged parts of the plant is also beneficial, as it can help improve airflow and reduce disease prevalence.
Common Eucalyptus Problems and Solutions
Brown Leaves
Eucalyptus trees are stunning additions to gardens but can face specific challenges. One common issue is brown leaves, which may indicate insufficient watering or a fungal problem. If you notice browning, first check the soil moisture; if it feels dry, increase your watering frequency. Eucalyptus prefers a well-draining soil that should be kept lightly moist. If fungal spots are visible on the leaves, it’s essential to remove the affected leaves to prevent the spread of the disease. Applying a suitable fungicide may also be necessary if the problem persists.
Falling Branches
Another frequent issue is falling branches. Due to their potential height and weight, eucalyptus trees can experience branch loss, particularly during windy or stormy weather. To mitigate this, consider regularly pruning heavy branches to reduce the tree’s overall weight and prevent breakage. Pruning also encourages healthy growth and improves air circulation, which can help minimize disease risks. Always prune during the summer months when the tree is actively growing, allowing for quicker recovery.
Final Thoughts on Eucalyptus Plant Care
Eucalyptus is a low-maintenance and fast-growing tree, offering year-round beauty and a refreshing aroma to any landscape. With the right care, this tree can be an excellent addition to gardens, whether in a pot or planted directly in the soil. From sunlight needs to the ideal watering schedule and overwintering techniques, mastering eucalyptus care allows gardeners to enjoy the beauty and fragrance of this Australian native without hassle. Happy planting!
