I have an horse chestnut tree which I planted about 22 years ago (when I was 6). It is still in a pot awaiting me to find somewhere to plant it. It is approximately 6 feet tall and appears healthy and has a great shape. It appears to be flowering this year and it made me wonder if it will produce full size conkers or whether I may have (inadvertently) made it into a somewhat large bonsai tree. Any thoughts? Also, will it affect the tree in the future if it is kept in a pot and will it grow as normal if I found somewhere to plant it?
Horse Chestnut Tree
Certified GKH Gardening Expert
You can grow any tree in a container as long as you have enough room for the roots and can provide the water it needs, which sounds like you've been doing thus far - 22 years is a long time. If the tree is healthy, I would leave it in its container, repotting only as needed. If it is flowering, then I see no reason why it shouldn't produce conkers, given it receives adequate pollination. You may also want to give it some phosphorus rich fertilizer or add bone meal to the soil. Should you decide to plant it out, this article will help: https://www.gardeningknowhow.com/ornamental/trees/horse-chestnut/how-to-grow-a-horse-chestnut-tree.htm