Germinating eucalyptus seeds successfully hinges on warm temperatures, high humidity, and careful handling to prevent root disturbance. DAYS TO GERMINATION can vary with temperature, with 7-10 days at 75-80°F (24-27°C) or 14-21 days at 65-75°F (18-24°C). Provide high humidity during germination for best results and transplant seedlings into flats or preferred seedling containers about 8-10 weeks before planting out.
Germination and sowing guidelines
SOWING: Transplant (recommended) - sow into 128-cell flats or preferred seedling container. Cover seeds lightly at the time of sowing. Bottom water or mist to avoid displacing seeds. Seedlings do not like root disturbance. Harden off and transplant outdoors after danger of frost. Solar mulch is recommended in areas with short growing seasons.
LIGHT PREFERENCE: Sun. PLANT HEIGHT: Varies. PLANT SPACING: 12-24". HARDINESS ZONES: Zones 9-11. Eucalyptus may be grown as a perennial in areas that receive no frost or with adequate protection from frost in cooler regions.
Harvesting and handling after germination
HARVEST: After leaves start to feel leathery and stems are woody. Fresh cut stems can be hung to dry or preserved in a glycerin and water solution. Preserving with glycerin will result in more durable and pliable dried stems that have the appearance of freshly cut foliage.
Soil, care, and uses
SOIL REQUIREMENTS: Well-drained, fertile soil. USES: Excellent cut or dried flower foliage. Accent in beds.
As with most aspects of growing native plants, there are many ideas, sometimes conflicting, on when eucalyptus seed should be sown. I have tried sowings at different times throughout the year and have also obtained the opinions of other growers of native plants. The following article is based on my experiences and findings and that of others. In most areas of Queensland seed of most species of eucalypts can be sown and reasonable germination can be obtained at any time of the year without using artificial heat. To do this, a sheltered position that is warmed by the sun is necessary. This is usually on the northern side of a building. Natural light and ventilation should be good, but it should be protected from heavy rain.
Although germination will occur right throughout the year, germination is usually slower, more uneven and percentage not as high during the period from May to mid-August. During this period germination may take from 2 to 3 weeks, compared to 3 to 10 days during spring and summer. As a general rule the best time for sowing eucalyptus seed appears to be early spring. I have had consistently good results by sowing during the first warm spell. The time of this will vary from year to year and from district to district, but in most areas of central and southern Queensland it can be from late August to mid-September. This is the time when most plants will commence to make new growth. Sowings can continue right throughout the summer with the prospect of good germination, but seedlings from sowing during the hottest period often have to contend with more pest and disease problems.
An exception to the early spring plantings are some tropical species of eucalypts. These give best germination if sowing is delayed until October or November when temperatures are higher, as they apparently need a higher optimum temperature for germination. Although reasonable germination can be expected from seed of most species of eucalypts in most areas of Queensland throughout the year, the optimum time for sowing appears to be spring and early summer, with the autumn period being the next most suitable time. The spring and early summer sowings have the added advantage in that the resultant plants will be of suitable size for planting out in the ground in the following March - April period.
Quick Facts: Evergreen trees or shrubs, Grown for their ornamental foliage and bark, Most are hardy and easy to grow, Plant in spring or summer, Like sun and well-drained soil, Prune to keep to a manageable size.
Choosing and buying eucalyptus
Choosing the right eucalyptus: Eucalyptus make striking specimen trees with year-round appeal - eye-catching bark and evergreen, grey-blue leaves. They generally have a light canopy that doesn't cast deep shade, despite being evergreen. Some can grow quite tall, ideal for large or medium-sized gardens, while others form shrubs or compact trees. Eucalyptus can grow rapidly, especially in the initial years - typically 1m (3⅓ ft) or more annually. Still, they can be pruned to keep them compact. Always check the eventual height before buying, to ensure the plant won't outgrow its space.
To explore the range of species, go to RHS Plants. Search for 'eucalyptus' to browse the photos and plant descriptions, and find out where to buy them.
What and how to buy
cider gum (Eucalyptus gunnii), snow gum (E. pauciflora subsp. niphophila), mountain gum (E. dalrympleana) - Plants are sold at various sizes, but smaller specimens - up to 1m (3⅓ ft) tall - tend to settle in more successfully.
Planting and care
Planting Where to plant: Eucalyptus thrive in full sun and well-drained conditions, and most soil types, including poor soils. Sheltered sites, protected from cold, drying winds - see our guide to assessing your microclimate. Large containers, ideally 60cm (2ft) or more in diameter. Most species dislike cold, frost-prone sites, shallow waterlogged soils, and exposed locations. With larger-growing species, plant them well away from buildings, as they can dry out the soil, especially heavy clay. See our guide to trees near buildings.
When to plant: Plant eucalyptus in spring and summer, so they have plenty of time to get established before winter.
How to plant: Eucalyptus trees are easy to plant and should settle in quickly, especially if you buy smaller specimens up to 1m (3⅓ ft) tall. Planting in the ground: Don't enrich the soil with manure or garden waste, as this will encourage too much leafy growth. There is also no need to stake young, small plants - they will develop stronger roots if unsupported. Take care to plant them in the right position, as they dislike being moved once settled in. For full planting instructions, see our guide to planting trees.
Planting in a container: Use a peat-free compost, such as soil-based John Innes No 2 or No 3. To improve drainage, mix in plenty of horticultural grit (up to 30 percent by volume). For full planting instructions, see our guide to planting in containers.
Ongoing care and maintenance
Watering: Water newly planted eucalyptus well, to help them settle in. After that, for the next few years until well rooted, you should only need to water during dry spells. Subsequently, watering isn't generally necessary. Many established specimens are drought tolerant. In containers: Keep the moisture consistent throughout but avoid waterlogging; reduce watering in winter.
Feeding: Most established trees growing in the ground don't need feeding. However, it can be beneficial to feed eucalyptus that have just been hard pruned, particularly if the tree isn't growing strongly. An application of Vitax Q4 or pelleted poultry manure according to the instructions on the pack in spring will give them a boost. In containers: Feed monthly with a general-purpose liquid fertiliser throughout the growing season (April to September). Re-pot every two years into a slightly larger container with fresh compost.
Weeding and Mulching: For the first few years after planting, maintain a circle of bare soil around the base of the trunk, about 1m (3⅓ ft) in diameter, to reduce competition for water. Once settled in, dense planting around the base can help to restrict growth if required by limiting rainfall reaching the roots. Lay a thick layer of mulch annually in early spring or autumn using chipped material and keep a gap of about 7.5 cm (3 in) around the trunk to deter rot.
Overwintering: Widely available species are generally hardy and need no protection over winter. For container-grown plants, move them to a sheltered spot against a south- or west-facing wall to stay a little warmer and prevent waterlogging. Raise containers on feet or bricks to keep drainage holes clear.
Caring for older plants: Eucalyptus trees are long-lived and healthy if grown in suitable conditions, needing little ongoing care. If too large for their site, you can coppice or prune them to reduce size. Propagating is best done from seed, as they are extremely difficult to root.
Propagation and common problems
Propagating: The best way to make new eucalyptus plants is to grow them from seed. To grow from seed: Collect when the seed capsules split easily. They can take a year or more to ripen on the tree. Put the seeds of hardy species in a fridge (3-5°C / 37-41°F) for two months. Sow seeds in mid February into deep pots (root trainers), as eucalyptus plants dislike root disturbance. Use peat-free and, if possible, provide bottom heat to encourage successful germination. Plant them into their permanent positions by mid-summer to give them the best chance of settling in well.
Problems: Eucalyptus suffer from few problems, but you may occasionally come across eucalyptus gall wasp, oedema, and honey fungus, which can affect leaves and roots if conditions are unfavorable. Look for tiny swellings on leaves (pinkish-brown galls) and symptoms of waterlogged soil. Honey fungus can appear as golden-brown toadstools in autumn and can kill the tree if untreated.
HOW TO GROW EUCALYPTUS FROM SEEDS TO GERMINATION || Shiela Jolo
In summary, eucalyptus cultivation from seed combines seasonal timing with careful moisture and light management, followed by proper transplanting and ongoing care to ensure strong, healthy trees capable of delivering ornamental foliage, bark interest, and resilience in suitable climates.