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?
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
I have a Horse Chestnut tree I planted about 12 years ago. It's approximately 12 feet high and seems to be healthy. I have yet to get any flowers on it though. Any thoughts on this?
I am not really certain why your tree has not produced blooms, other than possibly a lack of phosphorus in the soil. I am assuming that it is planted in an area receiving sun, as you state it is flourishing. Normally, these trees will develop blooms within the first 4 years. Perhaps there is a problem with pollination. I am sorry I cannot be of more help to you, as this has me baffled as well.
I have grown a horse chestnut tree/sapling from a conker. It is about 7 foot tall and has a lot of small branches on the 'trunk'. I guess these should be removed. If so, how and when, and are there precautions I should take?
This article has information about horse chestnut. It advises pruning in late winter. https://www.gardeningknowhow.com/ornamental/trees/horse-chestnut/how-to-grow-a-horse-chestnut-tree.htm
No special approach to pruning, just cut the little branches off flush with the trunk, using a hand pruner or saw.
I have a massive horse chestnut and my neighbors at the back of me want to have it to topped. I'm not too happy with this, as I've read how damaging it is to the tree. Please could you advise me on this? Thank you.
I would share the information in the article below with your neighbors. Topping trees permanently disfigures and damages the tree, and may even kill it.
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-topping-information.htm
I have a potted horse chestnut tree that has a lot of grass and weeds in the pot. I think this is hindering the growth of the tree. What is the best way to get rid of the weeds and keep them out?
Hand-pulling is probably the best way to get rid of the weeds and then add a layer of mulch to keep new ones from sprouting. Use a weed killer on it may harm the tree.
I need to remove side shoots from a young Horse Chestnut tree and wondered how best to propagate them.
Here is a link with growing information and how to propagate the trees.
I was given 3 large seeds from the pods of the Horse chestnut tree. How and when do I plant them to start a tree?
Here is an article that will help you.