eucalyptus

How to Plant and Grow Eucalyptus

Eucalyptus, known for its pleasantly scented leaves, particularly the Eucalyptus cinerea, is a favorite among gardeners. Discover the methods to grow and nurture this delightful plant.

Table of Contents

Introduction

Eucalyptus plants, particularly Eucalyptus cinerea, are often recognized as a preferred food source for koalas. In its native Australian habitat, this evergreen tree can reach heights of nearly 60 feet. However, in domestic gardens, it generally grows to a more manageable size of about 6 to 10 feet tall. The tree is characterized by its reddish-brown bark, which peels away on its smaller branches. Its leaves, ranging in color from silvery to blue-green, release a distinctive menthol-like scent when crushed. The ideal time to plant eucalyptus trees is during the spring. They exhibit rapid growth, potentially adding several feet each year. It is crucial to be aware that the bark, leaves, and sap of the eucalyptus are poisonous to both humans and animals.

eucalyptus-flower

Characteristics

Common Name and Botanical Aspects

  • Common Name: Eucalyptus, also known as silver dollar tree or argyle apple
  • Botanical Name: Eucalyptus cinerea
  • Family: Myrtaceae
  • Plant Type: Tree
  • Size: Grows 6–53 ft. tall, and spreads 2–15 ft. wide
  • Sun Exposure: Needs full sun
  • Soil Type: Prefers well-drained soil
  • Soil pH: Suitable for acidic to neutral soils
  • Bloom Time: Flowers in summer
  • Flower Color: White and red
  • Hardiness Zones: Suitable for USDA zones 8–11
  • Native Area: Originally from Australia
  • Toxicity: Harmful to people and pets

Eucalyptus Plant Care

For successful outdoor cultivation of eucalyptus plants, start by selecting a sunny location with well-draining soil. It’s important to ensure that no surrounding trees or bushes shade the young eucalyptus, and there should be ample room for the tree to reach its full height and width. When planting multiple eucalyptus trees, maintain a minimum distance of 8 feet between them.

Eucalyptus trees typically grow well without the need for staking or other structural support. They are also adaptable to container planting and indoor environments, provided they receive sufficient light.

Apart from appreciating their aesthetic appeal, you can harvest eucalyptus for various purposes. For the best yield, wait until later in the growth season to collect mature leaves and branches. To harvest leaves alone, use pruners or simply pluck them by hand. Dry the leaves on a paper towel or drying rack in a cool area away from direct sunlight. When the leaves become slightly leathery or crispy, store them in airtight glass jars.

Light

Eucalyptus thrives in bright conditions, so place your plant in a part of your garden that gets a minimum of six hours of direct sun each day. Similarly, when growing eucalyptus indoors, position it close to a window that receives ample light, ideally a south-facing one.

Soil

Eucalyptus is adaptable to various soil types; however, it is essential for the soil to have efficient drainage. For those grown in containers, choose a potting mix that ensures good drainage. The optimal soil pH for eucalyptus ranges from slightly acidic to neutral.

Water

Once established, eucalyptus can withstand short periods of drought. However, prolonged dryness is not favorable and may lead to leaf drop. A practical approach to watering is to check the soil moisture by inserting your finger into the soil; if it feels dry at the tip, it’s time to water. Typically, this means watering on a weekly basis, particularly for container-grown plants, in the absence of rain.

Temperature and Humidity

Eucalyptus flourishes in warm conditions, ideally within a temperature range of 65 to 75 degrees Fahrenheit, and it thrives in moderately humid environments. Exposure to temperatures below 50 degrees Fahrenheit for extended periods can be detrimental to the plant. Therefore, if your eucalyptus is in a container and cooler weather is anticipated, it’s advisable to move it indoors.

Fertilizer

For eucalyptus plants cultivated in the ground, fertilization is usually unnecessary. In contrast, those grown in containers tend to exhaust their nutrient supply faster. Therefore, it’s recommended to fertilize these plants using a low-nitrogen fertilizer formulated for houseplants during the growing season, adhering to the guidelines provided on the product label.

Varieties of Eucalyptus

Besides Eucalyptus cinerea, there are numerous other species of eucalyptus, such as:

  • Eucalyptus globulus: Also known as blue gum, this variety is recognized for its smooth bark and adaptability to diverse growing environments.
  • Eucalyptus gunnii: Often called cider gum, this species is more resistant to cold compared to many other eucalyptus types.
  • Eucalyptus platypus: Known as moort, this particularly resilient species is well-suited for heavy soils and can withstand cold temperatures and drought conditions.

Pruning

Eucalyptus trees typically require minimal pruning. Yet, it’s beneficial to trim branches that are overgrown, damaged, or oddly shaped to maintain the tree’s aesthetic appeal. Summer is the optimal time for pruning, but it’s advisable to avoid doing so in highly humid conditions.

Propagating

Eucalyptus trees are commonly started from seeds bought or acquired from nurseries, as trees in home gardens seldom bloom and produce seeds. They can also be propagated from cuttings, although this method may not always be successful. However, it’s a cost-effective and convenient approach to acquiring a new plant, particularly since eucalyptus might be scarce in garden centers. The ideal time for taking cuttings is when the tree is aged between 2 and 12 months, as rooting older stems can be challenging. Late summer is the best period for this process. Here is a guide to propagating eucalyptus from cuttings:

  1. Prepare a small pot with a mix of 3 parts composted tree bark and 1 part perlite. Incorporate slow-release fertilizer as per the instructions for the pot’s size. The growing medium should be moistened.
  2. Use sterile pruning shears to snip a stem about 5 inches long, with four to eight leaves, just above a leaf node.
  3. Strip off the leaves from the lower half of the cutting.
  4. Dip the cut end into a rooting hormone, then plant it in the growing medium, nearly up to the leaf level.
  5. Position the container in a spot with bright, indirect light, in a room maintained at around 70 degrees Fahrenheit. Ensure that the soil stays slightly moist.
  6. Roots typically develop within a month. At this stage, you can relocate the new plant to a sunnier location and gradually extend the intervals between watering. When the weather becomes warm enough, acclimatize it outdoors for increasingly longer periods before planting it in the garden.

How to Grow Eucalyptus From Seed

To successfully grow eucalyptus from seed, it’s important to first chill the seeds in a refrigerator for two months prior to planting. Start the sowing process indoors in late winter, about 10 to 12 weeks before the anticipated last frost date in your area. Utilize a seed-starting mix and plant the seeds in peat pots, which can be directly transplanted into the ground later to minimize root disturbance.

Scatter the seeds on the surface of the growing medium, lightly covering them. Position the pots in a warm location with bright, indirect light. Maintain the moisture of the growing medium by misting it, ensuring it stays moist but not waterlogged. The seeds typically sprout within two to three weeks. When the seedlings reach approximately 6 inches in height, they are ready to be moved outdoors.

Potting and Repotting

Eucalyptus plants are frequently cultivated in containers, especially outside their natural hardiness zones. Container growing enables gardeners to shield their eucalyptus from cold weather by moving them indoors. However, due to the rapid growth of eucalyptus, many gardeners opt to treat these container plants as annuals, starting anew each year. This strategy helps keep the plants at a manageable size for indoor, balcony, and deck spaces.

Eucalyptus plants prefer stable root conditions, so using a large container from the start is advisable to avoid the need for repotting. A 5-gallon container is typically sufficient. While unglazed clay pots are great for allowing excess moisture to escape, a lighter plastic container may be more convenient for moving. Regardless of the material, ensure the container has sufficient drainage holes. A high-quality, fast-draining potting mix is essential for the health of the plant.

Overwintering

When cultivating a eucalyptus plant in a container outside its natural hardiness zones, it’s crucial to bring it indoors during winter to ensure its survival. Exposure to frost should be avoided as it can harm or even kill the plant’s foliage. For the winter months, position the plant near your brightest window, ideally one facing south. During this period, refrain from fertilizing the plant and reduce the frequency of watering.

Common Pests and Diseases

Eucalyptus plants generally don’t encounter significant problems with pests or diseases. However, there might be instances of eucalyptus long-horned borers, particularly in plants that are under stress. Indications of an infestation include holes in the bark, sap leakage, and changes in leaf color. In case of an infestation, promptly remove the affected part of the plant, since insecticides are ineffective against these borers.

Typical Issues Encountered with Eucalyptus Plants

Eucalyptus trees generally maintain good health in their ideal conditions. Yet, they may face some challenges when grown in less than optimal environments.

Leaves Turning Brown

Browning leaves on a eucalyptus tree often indicate insufficient moisture, particularly if the leaves are also curling or falling off. If this is observed, increase watering to maintain a consistent but not overly saturated soil moisture. Additionally, brown leaves might signal a disease, commonly fungal in nature. If the issue is localized, quickly remove the affected section. Alternatively, applying a suitable fungicide may be necessary.

Benefits of Eucalyptus

Eucalyptus, a genus of over seven hundred species of flowering trees and shrubs, is known for its distinct aroma and various uses and benefits, both in its natural form and as an extracted oil:

  1. Aromatherapy and Respiratory Relief: Eucalyptus oil is widely used in aromatherapy. Its strong, refreshing scent is known to help clear nasal passages, relieve sinus congestion, and ease symptoms of respiratory conditions like colds, coughs, asthma, and bronchitis.

  2. Antimicrobial Properties: The oil extracted from eucalyptus has natural antimicrobial and antiseptic qualities. It is often used in personal care products like mouthwash, toothpaste, and topical creams to reduce bacteria and treat minor wounds, cuts, and skin infections.

  3. Pain Relief: Eucalyptus oil is sometimes used in products designed to relieve pain. It can be applied topically to soothe muscle pain, strains, and sprains, thanks to its anti-inflammatory properties.

  4. Stress Reduction: The scent of eucalyptus is believed to be relaxing and can help in reducing stress and anxiety. It is often used in spas and for relaxation therapies.

  5. Insect Repellant: Eucalyptus is a natural insect repellent. Its oil can be used to ward off mosquitoes and other pests, which makes it useful for outdoor activities.

  6. Air Purification: Growing eucalyptus trees can help in purifying the air. They are fast-growing and have a high rate of transpiration, which means they release a lot of water vapor into the air, potentially improving air quality.

  7. Gardening and Landscaping: In their natural form, eucalyptus trees are often used in landscaping for their attractive foliage, interesting bark, and fast growth. They can provide shade and act as windbreaks in suitable climates.

  8. Mental Focus: Some people find that the aroma of eucalyptus oil helps to enhance concentration and mental focus.

However, it’s important to use eucalyptus oil safely. It should be diluted before applying to the skin and should not be ingested. People with allergies or sensitive skin should be cautious, and it’s always advisable to do a patch test before widespread use. Additionally, eucalyptus oil should be used with caution around pets, as it can be toxic to them.

FAQs

How fast does eucalyptus grow?

The growth rate of eucalyptus is significantly influenced by how well its natural habitat is replicated. In ideal conditions, eucalyptus is known for its rapid growth, often gaining several feet annually.

Can I plant eucalyptus outside?

Eucalyptus is suitable for outdoor growth in USDA hardiness zones 8 to 11. Additionally, it’s feasible to maintain a container-grown eucalyptus outside during warmer seasons and then move it indoors for overwintering when temperatures fall below 50 degrees Fahrenheit.

Why should you not plant eucalyptus?

Although not classified as invasive, eucalyptus trees can disrupt the ecological equilibrium in non-native environments by competing with indigenous plants for resources. Additionally, they are poisonous to both humans and pets.

Is eucalyptus easy to grow?

Growing eucalyptus outside its native habitat can be challenging, but with ample sunlight and warmth, it has the potential to thrive vigorously.

Are eucalyptus leaves poisonous?

Yes, eucalyptus leaves are toxic when ingested, containing harmful compounds like eucalyptol. Consumption can cause symptoms such as stomach pain, vomiting, and in severe cases, impact the central nervous system and respiratory function in humans. They are similarly toxic to pets, with potentially more severe effects. Caution should be exercised to prevent children and pets from accessing eucalyptus leaves, and eucalyptus oil should be used carefully, adhering to dilution and usage guidelines.

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