How To Grow And Care For Eucalyptus

Eucalyptus is a versatile plant in the home and garden. Houseplant enthusiasts adore the fragrance it brings to the home. Eucalyptus makes a striking accent in landscapes with gorgeous foliage and colorful bark. Eucalyptus plants are easy to care for and can be grown in containers, maintained as a shrub, or allowed to mature into a tree. Plant in spring after all danger of frost has passed. Eucalyptus is a fast-growing plant that can grow 6 to 8 feet in a season, though it tends to stay smaller in cooler climates. It is often trained as a standard.

The aromatic foliage of eucalyptus takes on two distinct shapes: juvenile and adult. The silver coin-shaped juvenile foliage of silver dollar tree gives Eucalyptus cinerea its common name. This striking blue foliage is widely used in fresh and dried flower arrangements. Other species have elongated leaves, but all are known for the sharp, medicinal scent that comes from the oils in its leaves. In spring, small white flowers appear on mature trees. Plants can be pruned to maintain juvenile foliage and a more compact habit. When deciding where to plant eucalyptus, keep in mind the bark and leaves are toxic to people and the essential oils can be toxic to dogs, cats, and horses, too. Also, eucalyptus can become invasive in mild climates. In the South, the University of Florida IFAS does not recommend planting eucalyptus in Florida gardens as it is potentially invasive.

Plant Attributes

Eucalyptus Care

In locations where it is winter hardy, eucalyptus is commonly grown as a landscape tree or pruned to maintain a bushy habit for use as a windbreak or in mixed borders. In colder regions, eucalyptus must be overwintered indoors or grown as an annual shrub from seedlings planted in spring. Plants are drought-tolerant once established and resist deer browsing. Salt and wind tolerance makes eucalyptus useful in coastal landscapes.

Depending on where you live, some eucalyptus species are considered invasive and should be avoided in the landscape. In Florida, rainbow eucalyptus, E. deglupta, is a species of concern along with many others—you can search for potential invasiveness of the species you want to grow in the University of Florida database. Many Florida counties restrict the planting of eucalyptus. In California, several species including the blue gum tree, E. globulus, are considered highly invasive. Check local guidelines before planting eucalyptus and avoid species known to be problematic.

Light

Eucalyptus grows in full sun, requiring at least six hours of direct sun per day. Plant in an airy, sunny location that is sheltered from the wind.

Soil

Eucalyptus performs well in dry to medium soils with good drainage. Mix a little compost or topsoil into poor, sandy soils. Heavy clay soils should be amended with coarse grit. When planting, don't try to loosen or break up the roots, which are very sensitive to disturbance. Mulch around the base after planting to help retain moisture.

Water

Eucalyptus has low to moderate water needs. However, young plants and container plants require regular watering to support growth and establish roots. Water deeply to encourage deep rooting. Plants are drought-tolerant once established.

Temperature and Humidity

Native to arid climates, eucalyptus has low requirements for humidity. Though they are evergreen, cold-hardy species like silver dollar tree and cider gum (E. gunnii) require cool temperatures in winter to maintain their vigor, which can make it challenging to keep them indoors permanently.

In the garden, plants are not always reliably hardy in winter but will quickly regrow from the roots after a hard freeze. Most eucalyptus can be grown in the Coastal and Tropical South, or Zones 9-11. Silver dollar tree and cider gum can be grown in the Lower South, or Zone 8, but late freezes can damage the plant. Eucalyptus is more likely to stay the size of a shrub or small tree in areas that experience hard frosts.

Fertilizer

Eucalyptus plants growing in the ground outdoors don't require supplemental fertilizer. In poor, sandy soils, add some compost to enrich the soil at the time of planting.

Potted plants benefit from a slow-release fertilizer during the growing season. Apply fertilizer at half strength each month starting in spring and stopping after early fall. You don't want to encourage tender new growth in the fall, as cold temperatures could damage it.

Types Of Eucalyptus

Silver dollar tree is just one of over 700 species in the genus Eucalyptus, all native to Australia and some surrounding islands. In their native range, eucalyptus trees are called gum trees, which is reflected in many of the species names listed below. Due to its popularity in the florist trade, several species are available from seed companies and specialty growers. Others are sold as landscape trees or shrubs.

• Silver dollar tree (E. cinerea) has coin-shaped, blue-green foliage and can grow quickly to 40 feet, though pruning can keep it a more manageable size. This species may be grown from seed for cuttings and can be kept as a houseplant, though it can outgrow the space quickly.
• Cider gum (E. gunnii) is also fast-growing and can reach 80 feet in its old age if left unpruned. It has creamy, peeling bark and lance-shaped leaves.
• White-leaved mallee (E. albida) has bluish-gray, spade-shaped foliage and a shrubbier growth pattern. It grows 6 to 10 feet tall and wide and can be grown in containers.
• The silver-leaved mountain gum (E. pulverulenta) is among the most popular eucalyptus grown for cutting. The variety ‘Baby Blue’ produces exceptionally striking blue foliage.
• Forest red gum (E. tereticornis) has lance-shaped leaves that can be used for flower arrangements. New growth has a contrasting red color that can intensify in fall. If allowed, it matures into a slender, 40-foot tree with creamy, peeling bark.
• Eucalyptus 'Silver Drop' grows to about 6 feet and can be planted as a shrub or grown for cuttings. It has small, round, silver-green leaves.
• A dwarf hybrid, 'Moon Lagoon', has blue-green, spade-shaped leaves and also grows to 6 to 10 feet.
• Willow peppermint (E. nicholii) is notable for its slender gray-green foliage that adds delicate texture to arrangements. The selection 'Angus' is cold-hardy to Zone 7b and eventually grows to a 40-foot-tall tree.
  

Pruning

Unless you plan to grow eucalyptus as a tree, plants will require regular pruning to maintain their size. Gardeners looking to grow eucalyptus for cuttings will need to follow a regular pruning schedule. Different pruning methods can be used, depending on your goals. 

Coppice pruning is the secret to keeping eucalyptus plants producing that stunning juvenile foliage. This pruning method involves cutting the entire plant close to the ground in late winter or early spring when it is coming out of dormancy. Coppice pruning must be started when the plants are young—don't try it on a mature tree. Also, don't prune in fall or early winter, which will encourage the plant to produce tender new foliage that gets damaged by frost. To coppice prune, cut the main stem at 12-18 inches above the ground. Plants produce new shoots from the base, creating a multi-stemmed bush of juvenile foliage. Repeat coppicing every year or every few years to rejuvenate plants.

Eucalyptus plants can also be maintained as a hedge or large shrub. Begin pruning after the second growing season, removing about one-third of the height of each stem. In subsequent years, prune stems back by one-quarter. If plants are not well-branched, you can coppice prune as above to encourage branching, then begin pruning for height after two growing seasons.

To train your eucalyptus as a tree, you can remove the bottom 1/3 of side shoots each year until you achieve your desired branch height. Also, remove crossing and dead or diseased growth.

Propagating Eucalyptus

Eucalyptus is challenging to propagate from cuttings, so most gardeners grow them from seed. Cuttings must be taken from young plants or young shoots on a coppiced plant. Don't take cuttings in winter while the plant is in dormancy.

1. Cut the tip of a stem at least 4 inches long with sharp, sterile pruners. Remove the bottom leaves before planting, leaving one or two sets of leaves in place.
2. Dip the cut end into rooting hormone and then stick it in a well-draining, sterile potting mix in a small container. Keep the potting mix lightly moist and cover with clear plastic until the cuttings have rooted to help retain moisture.
3. Cuttings should be kept at around 70° F and will root better when provided with a half day of light. This may require artificial plant lights. Once the plants are well-rooted and begin to show new growth, begin to harden them off for transplanting outdoors.

How To Grow Eucalyptus From Seed

Eucalyptus grows very quickly from seed, making this an economical way to start new plants. Sow seeds indoors 10 to 12 weeks before the average last frost date for your area. 

1. Fill a seed tray or other shallow container with a seed-starting soil mix. Deeper cell packs work well for eucalyptus as they don’t like their roots disturbed. Make sure the container has drainage holes in the bottom.
2. Before sowing seeds, moisten the soil evenly until it is damp but not soaked.
3. Sow seeds on the soil surface and gently press into the soil before covering with a very thin layer of soil or fine sand.
4. Maintain a temperature between 65˚F and 75˚F during the day and night. Water trays from the bottom or use a mister to keep the soil moist without disturbing the seeds. Covering the seed tray loosely with plastic is an excellent way to maintain soil moisture.
5. Eucalyptus seeds are slow to germinate and benefit from a heating pad. Seedlings will emerge in 14 to 21 days or longer, depending on the species. Remove plastic when seedlings emerge and move seedlings off of the heat pad.
6. Provide seedlings with bright light for 14 to 16 hours per day. If supplemental lighting is needed, use a fluorescent plant light set 3 to 4 inches above the seedlings, raising it as plants grow.
7. If seeds were started in trays, transplant individually into 3- to 4-inch pots when the first true leaves emerge. For plants intended to be grown indoors, wait to transplant into individual pots when plants reach 4 to 5 inches.
8. Begin hardening off seedlings about one week before transplanting into the garden or outdoor containers. 

Potting And Repotting Eucalyptus

Eucalyptus makes a wonderful houseplant if you can keep it to size and provide adequate lighting, but be aware that it is toxic to pets. Start with high-quality potting soil containing perlite or coarse sand to promote drainage. Use a container one or two sizes larger than the existing one and make certain it has a drainage hole. Eucalyptus plants need plenty of light and perform best in a south-facing window.

Provide regular watering during the growing season and reduce irrigation frequency during the winter. Because eucalyptus grows quickly, plants may require repotting each spring. Size can be maintained by pruning foliage back hard after the growing season. You can also try coppicing the plant in spring every few years. Eucalyptus does not like to have its roots disturbed, so handle it carefully when repotting. Cold-hardy species may appreciate being moved to a cooler location over winter.

Overwintering Eucalyptus

If you live outside the hardiness zone for eucalyptus, you will need to move plants to a sheltered area before the first frost to store them over winter. Container plants generally need sheltering in climates that experience frost. Move it into a greenhouse, garage, or shed where the temperature is cool but stays above 45° F. This allows the plant to have a period of dormancy, or rest, before spring arrives. Eucalyptus does not shed its leaves and will need adequate light.

Another way to maintain eucalyptus over the winter is to stool them and store them in a cool, dark basement or frost-free garage. Stooling is a pruning method that removes the foliage, leaving only the stems and roots to overwinter in a dormant state. To stool bushy plants, cut stems back to the ground as you would when coppicing. Plants grown as a standard can be stooled by cutting the branches back to the trunk.

Eucalyptus can also be overwintered as a houseplant. When bringing eucalyptus indoors in the fall, isolate plants for a few weeks to make sure they are pest-free before introducing them to other houseplants. Place eucalyptus in a bright window and reduce watering over the winter months.

Common Pests & Plant Diseases

Historically, eucalyptus is not bothered by any serious insect or disease pests in the Southeast. Two psyllids (jumping plant lice) that originate from Australia and feed on eucalyptus have been found in California and Florida. The larvae leave behind crystallized white honeydew. Insecticidal soap is effective in controlling the problem on small plants.

In humid conditions, powdery mildew can develop on foliage. Maintain good air circulation around plants to minimize the occurrence. Eucalyptus is accustomed to arid conditions and can be sensitive to overwatering. Inadequate drainage or excessive watering can lead to root rot. Site plants accordingly and manage irrigation to prevent waterlogged roots.

Fungal diseases can cause leaf spots, root rot, or cankers. When pruning away diseased stems, disinfect pruners between each cut. Spraying diseased foliage in spring with a fungicide may help control the problem. Older trees with heart rot need to be removed.

Common Problems

Eucalyptus does well in Southern gardens, though it can suffer damage in harsh winters. Here are two other problems to watch out for.

Curling, Crispy Leaves

Container plants or newly transplanted trees can dry out quickly. Water deeply when the soil is dry until the plant is established. Hot weather may require more frequent watering. Also make sure that you are not overwatering the plant and improve drainage if needed. Finally, root-bound plants can have difficulty getting enough moisture and nutrients and should be repotted.

Dropping Leaves

Eucalyptus trees naturally drop mature leaves each year. Trees also shed leaves as a defense during periods of drought. If your plant is in a container, make certain you are providing adequate water. The same goes for trees in the ground during long, hot dry spells.

Eucalyptus leaves do not break down easily and can become a fire hazard in dry climates. Rake and remove leaves if they are beginning to build up under the tree.