Oak trees (Quercus) are some of the most widespread trees in woodlands, yet their population has been shrinking. A major reason for this decline is that wildlife relies heavily on acorns and young shoots for food. You can help restore their presence by growing and planting oak seedlings, following this guide.
Growing oak trees
The English oak (Quercus robur) grows best in rich, well-drained soil with plenty of sunlight or light shade. Planting an oak isn’t just about adding a tree to your garden—it’s about leaving behind a living legacy for generations to come.
Where to Plant Oak Trees
You can grow oak trees in gardens, but they need plenty of space. A mature oak can spread up to 25m x 25m, so unless you have room for such a large tree, it’s better to train it as a hedge. Oaks thrive in sunny or partially shaded spots and adapt well to most moist, well-drained soils. Avoid planting in areas that stay waterlogged, particularly if you’re growing sessile oak. Keep in mind that oak can be toxic to pets if they eat it.
How to Plant Oak Trees
The best time to plant an oak is during its dormant phase, typically in winter. This gives the roots time to establish before growth starts in spring.
Follow these steps for successful planting:
- Soak bare-root oak saplings in water for approximately one hour before planting, and thoroughly water container-grown trees.
- Clear the planting area of perennial weeds and grass.
- Dig a square hole that matches the depth of the roots and is at least twice their width.
- If the soil is compacted, loosen the sides of the hole with a garden fork.
- Spread out the roots, keeping the soil mark on the stem level with the surface. Backfill gently, firming soil around the roots.
- Insert a stake to stop root rock and secure the sapling with a tree tie.
- Water well, then add a thick mulch to retain moisture and suppress weeds.
- Check tree ties every spring and autumn. After two growing seasons, the stake can usually be removed as the oak will be strong enough to stand on its own.
How to Grow Oak Trees from Acorns
Starting oak trees from acorns is a fun autumn project for both kids and adults. For the best results, pick healthy acorns—plump, brown, and free from damage. Plant them quickly after they fall so they don’t dry out. A ripe acorn will usually separate easily from its cup and is ready for sowing.
Follow these steps to grow oaks from acorns:
- Select a pot at least 15cm deep to allow space for the oak’s long taproot. Ensure it has good drainage holes.
- Fill the pot about three-quarters full with peat-free compost, mixing in a little grit to improve drainage.
- Place the acorn on its side and cover it with 2–3cm of compost.
- Water lightly, then set the pot in a sheltered spot with good light but protected from rain—such as a cold frame or unheated greenhouse.
- Shield the acorns from birds and other wildlife.
- Once germination begins in spring, keep the compost consistently moist.
- When the seedling reaches about 25cm tall, move it to a larger pot for further growth.
How long does it take for oak trees to grow from acorns?
After the first year, you can transplant your oak seedling into the ground, although it can remain in a larger pot for an additional year if needed. Under good conditions, English oaks grow about 50cm each year. However, patience is key, as these trees typically take around 40 years to begin producing acorns.
Oak Tree Care
Young oak saplings need careful attention in their early years, as wildlife often feeds on them. Protect newly planted saplings with cages, and as they grow, replace the cages with chicken wire fencing. Keep the tree protected until it reaches about 5 feet (1.5 m) tall. As part of proper oak tree care, make sure the soil around the tree stays free of weeds, and water regularly if there is no rainfall, since oaks cannot establish strong roots in dry soil. Avoid using fertilizer during the first year. From the second year onwards, only feed the tree if its leaves look pale or its growth seems unusually slow. Remember that oak trees grow slowly at the beginning, and trying to force faster growth with fertilizer can actually weaken the wood, causing trunk splits and broken branches.
Would you like me to also
Pruning an Oak Tree
Oaks are generally low-maintenance and require little pruning beyond removing damaged or crossing branches, which is best done in late autumn or winter. We advise against pruning during summer, as this can disturb nesting birds. If you are maintaining oak hedges, trim them in September to keep them at the right height. Smaller hedges may be cut in summer, but only after checking carefully to ensure no birds are nesting inside.
Pests and Diseases
Like many other trees, oaks can be affected by pests and fungal diseases. Powdery mildew, for example, is a common fungal problem that produces a white, powdery coating on the leaves. It tends to appear on fresh summer shoots, known as Lammas growth. Honey fungus is another serious issue that can cause root and branch dieback, and in severe cases, kill the tree. Although clusters of honey-colored mushrooms sometimes appear in autumn, they are not always visible, making early detection difficult. This fungus is believed to contribute to the broader issue of oak decline.
Despite these risks, oak trees play an essential role in supporting wildlife. Their leaves provide food for a wide variety of insects, including aphids and caterpillars. While most of these insects do little lasting harm to the tree, they form a crucial part of the food chain. Winter moth larvae, for example, are a vital food source for birds like blue tits. A single brood of chicks can consume more than a thousand caterpillars every day, with winter moths being their top choice. This balance makes oaks invaluable not just as majestic trees, but as thriving ecosystems in their own right.
