Eucalyptus gunnii, also known as Cider Gum, is a popular evergreen tree native to Australia. It is known for its attractive, peeling bark and fragrant, blue-green foliage. Eucalyptus gunnii can be grown successfully in the UK, providing a unique and eye-catching element to your garden. Here are some guidelines for growing Eucalyptus gunnii in the UK:

1. Location: Choose a sunny and sheltered spot in your garden. Eucalyptus gunnii requires plenty of sunlight (at least 6 hours per day) to grow well. Ensure the location is protected from strong winds, as this fast-growing tree can be susceptible to wind damage.

2. Soil preparation: Eucalyptus gunnii prefers well-draining soil and can tolerate a range of soil types, including clay, loam, and sand. However, it is essential to ensure good drainage to prevent waterlogging. If your soil is heavy clay or poorly drained, consider adding organic matter, such as compost or well-rotted manure, to improve drainage.

3. Planting: Dig a hole that is twice the width and depth of the root ball of your Eucalyptus gunnii. Place the plant in the hole, ensuring that the top of the root ball is level with the surrounding soil. Fill the hole with the soil mixture, gently firming it around the roots. Water the plant thoroughly after planting.

4. Watering: Water your Eucalyptus gunnii deeply and regularly during its first growing season to help it establish a healthy root system. After this initial period, you can reduce watering, as Eucalyptus gunnii is relatively drought-tolerant once established. However, be sure to provide extra water during hot, dry spells.

5. Fertilizing: Apply a balanced, slow-release fertilizer in the spring, following the manufacturer's instructions. This will provide your Eucalyptus gunnii with the necessary nutrients for healthy growth.

6. Pruning: Eucalyptus gunnii can be pruned to maintain a desired size and shape or to encourage bushier growth. Prune in late winter or early spring, removing any dead, damaged, or crossing branches. For a smaller, more shrub-like appearance, you can coppice the tree by cutting it back to the ground every few years. This will promote the growth of new, straight stems with juvenile foliage.

7. Winter protection: Eucalyptus gunnii is relatively cold hardy (down to around -15°C), but younger plants or those in colder areas may benefit from some winter protection. Wrap the trunk in horticultural fleece or bubble wrap to insulate it from cold temperatures and harsh winds. You can also add a layer of mulch around the base of the tree to protect the roots from freezing temperatures.

By following these guidelines, you can successfully grow Eucalyptus gunnii in the UK, adding an attractive and aromatic element to your garden. Keep in mind that Eucalyptus trees can grow quite large, so ensure you have enough space for the tree to develop and thrive.