Memorial tree ideas please

I think an amelanchier is a good choice too
though not very "showy". No trouble, no pruning, and in a poor soil which has been lawn it will struggle a bit and may flower better and stay smaller.
Much as I love Sorbus (Rowan) they are prone to disease and sometimes die for no apparent reason, which would be sad for you.
Another good alternative is a pear. It may not fruit immediately but if you go to a garden centre and get a "patio" type on a dwarfing rootstock it will fruit more quickly and stay small, so no complicated pruning required. If you put it in the ground rather than a pot it would grow to a decent size but still small. Usually there is a pear tree in a garden near you so pollination shouldn't be a problem - though you could have two that flower at the same time.
We have a Doyenne de Comice which we neglect but which is now covered with fruit every year.
A quince is a pretty large tree. We bought a naturally dwarf variant but the fruit is not good, however you ripen or cook it there is none of the true quince flavour.

Kate54, our family has planted trees/shrubs for various occasion, from births and deaths to weddings/anniversaries. We have tended to choose trees that would represent the person/s in question.
The Japan quince is pretty and the fruit makes nice jelly, not quite like the tree’s but nice nevertheless.
I love the fact that people will be planting trees in memory of an event/loved one.

Amalanchia beautiful, if soil poor you could try a fig...grows really well in poor soil

A weeping pear is beautiful and I think would make a lovely memorial tree.

Libman

Rowan trees are lovely but they can get very tall..

These are pretty and can be grown in a large pot or pruned to keep them small.
Flamingo Willow Salix Integra Hakuro Nishiki

I have to agree with Libman on the Flamingo Willow Salix Integra Hakuro Nishiki
I have one in my garden and so pretty. I've had it for a couple of years and hasn't grown that much.
I know they have sold them in the past at the B&Q garden centre although I bought mine online.

A suggestion, have you asked some of the garden centres, near you, to mail a catalogue of trees? Then you will have a fair idea as to how different all of the trees are. A height guide as well is handy! Just a thought. ?.

Thanks so much again for all your contributions. Choosing a tree which ‘echoes’ the person being remembered sadly doesn’t apply in this case as our son had a severe learning disability and, although he had likes and dislikes, never showed much interest in trees!
I want the tree in the middle of the small lawn so that it can be seen from the kitchen window. It needs to be quite small and you have kindly suggested lots of options.

Amelanchier are good trees and if you are short of space they can be in columnar style too. Lovely blossom, easy to keep, very hardy too.

Amelenchier is getting a lot of votes!

And, great news, my research tells me that among the many alternative names for this tree, is Juneberry. My son’s birthday was in June.

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.

I have a rose bush named Margaret after my grandma, I also bought mum one a couple.of years later, mine is thriving but hers does flower every year.
Worth googling the persons name who the tree will be in memory of to see there is anything with their name in that might be suitable. I would have loved a magnolia tree, but they grow to big for the size of garden i have.

I have a small garden at the back of my house that has two rowan trees, a plum, a fig and a birch. One of the rowans is very well established, but is a beautiful size for the garden and provides interest all year.

In 2020 I had a mulberry tree planted in the local park to commemorate my son-in-law’s 10 year anniversary. I chose that particular tree because it’s grows prolifically in Afghanistan where he died.