cornus (dogwood) are very good as you can keep them down as a shrub if that suits. I want my cake and eat it, so when they tell you to cut the stems right down each year so that you get the new colours in the winter which are great. I do a mix. So cut down about half the older stems but leave some so I get some leaves and blossom etc. But the great thing with cornus is that you can get red, acidy green and very dark reddish and also cornus midwinter has lovely mixed colours but I dont think is as strong as the others. If you have the opportunity to go to an rhs garden like harlow carr and see their winter garden you will see the effect and it is lovely to have that winter colour shine out when there is not much else. I also love to grow lonicera purpusii or lonicera frangrantissima . These are winter flowering honeysuckles which do not have a load of blossom but oh the perfume in winter is wonderful. Anyone who has a bigger space I planted the lovely katsura tree. It has heart shaped leaves, beautiful autumn colour and the leaves then smell of burnt toffee or candy floss. Absolutely wonderful to me and have got children to smell a handful of autumn leaves. They look at me as though I am mad when I offer them the leaves but their eyes go round when they smell them. I have to remind them they cant eat them! I planted it in my last garden which I loved. Have had to move but am pleased to say that I sold it to a very keen gardener and am comforted that my lovely cornus and trees and snowdrops and hellebores are being enjoyed by another gardener. I also agree with an earlier post that prunus serrula has the most wonderful red polished bark and you just must stroke it it is so lovely. If people would like to plant a tree in memory of someone but do not have the space or perhaps are renting and not allowed to plant trees may I suggest supporting the Woodland Trust. Over the years I think I have planted a small wood for happy and sad occasions in my family. My parents ruby wedding we four children gave money to plant four trees. My second marriage, my 3 day old grandaughters death, my husbands death, making a special memory of being friends with someone for over 60 years, celebrating my brothers significant birthday etc etc. So , dont know if it is different now but you can see where they are planting in Britain and choose one of those areas for your tree to be planted and they will give you a grid reference so you know where it is, but there is no plaque or anything . We are from Yorkshire and have planted a lot of trees in the north but my parents had moved to Hertfordshire and for their ruby wedding we planted trees in the chilterns and we hope this next summer to be able to meet up and go for a walk and see how they are getting on. with illness and covid etc the family have not met up for a long time and my parents are now dead but we hope to go and visit the trees and they should be quite established by now. So if you really fancied some big tree that is totally wrong for where you live , I think this is quite a good idea. My view is that our family have taken from the world and this is a little way of giving something back and hopefully helping with the climate situation and giving our descendants a good environment and hoping that our children and others will continue in the same way.