To keep native UK trees fairly small in size, you can employ various pruning and maintenance techniques. Here are some general tips:

Regular Pruning:

• Prune your trees during the dormant season (late autumn to early spring) to minimize stress on the tree.
• Remove any dead or diseased branches first, followed by any crossing or rubbing branches. This helps maintain the overall health of the tree.

Choose the Right Tree Species:

• Research and select native tree species that naturally have a smaller growth habit. For example, consider planting a crabapple tree (Malus sylvestris) instead of a large oak tree.

Early Training:

• When the tree is young, selectively prune to shape it. Remove competing leaders (main upward-growing branches) and encourage a single, central leader for a more compact form.

Pollarding or Coppicing:

• Pollarding involves cutting back the upper branches of a tree to a certain height. This can be done every few years to maintain a smaller size.
• Coppicing involves cutting the tree back to ground level periodically, promoting the growth of new shoots. This is more suitable for certain deciduous species.

Root Pruning:

• Root prune during the dormant season using a sharp spade or shovel. Cut a circle around the tree, staying within the tree's dripline (the outer edge of the canopy).
• Keep in mind that excessive root pruning can stress the tree, so it should be done gradually over a few years.

Container Planting:

• Choose a large container with proper drainage for your tree. Use high-quality potting soil.
• Regularly check the roots and consider root pruning when repotting. Be mindful of the tree's nutrient requirements.

Mulching:

• Apply a 2-4 inch layer of organic mulch around the base of the tree, keeping it a few inches away from the trunk.
• Mulching helps retain moisture, suppress weeds, and regulate soil temperature.

Watering and Nutrient Control:

• Provide consistent watering, especially during dry periods. Avoid overwatering, as it can lead to rapid growth.
• Use a balanced, slow-release fertilizer in spring, but avoid excessive fertilization.

Regular Monitoring:

• Inspect the tree regularly for signs of pests, diseases, or nutrient deficiencies. Address issues promptly to minimize stress.

Consult an Arborist:

• If in doubt, seek advice from a certified arborist. They can assess the health of the tree, recommend appropriate pruning techniques, and provide guidance on long-term care.