Tree planting (4m spread after 20 years) - how close to fence?

How do you factor in the prediction/possibility that a tree will have a spread of 4m after 20 years when planting - the 2 trees I have bought are less than 2m tall atm - a single stem Rowan (Embley) and an amelanchier x grandiflora "Ballerina" or Juneberry tree (it divides low down so looks like a 2-pronged fork - fairly evenly balanced atm). Both are predicted to spread to 4m. Do I have to plant them 4 apart so they don't overlap? Do they really have to be 2m from the fence? What mistakes have you made with tree planting that, given your time over again, you'd do something different? if I set the pot down between my feet I'd like to plant them and arm-stretch away from the fence (about 1m) - is that something I'll live to regret?

 

Well, if you really want to put them in those positions you can - just be prepared to prune or indeed remove them if need be. Think about the potential impact on the neighbours, as well as on your own garden. I've had this small garden over thirty years now and thought it might be helpful to do a roll call of the trees I've had in it:

1) Some kind of tall blue conifer, planted by an earlier occupant. Got the chop fairly early on as it was rather an ugly shape and getting too large.

2) A bay tree, planted by me next to the patio. Removed by me after 10/15 years when it grew too large - hard to prune and overshadowed the patio, plus it had a persistent scale insect infestation (this tends to happen when they are kept pruned close and the air can't get in)

3) A Golden Hornet crab apple, planted by me. Lovely tree, lasted about 10 years, but it got woolly aphid very badly - my garden is pretty sheltered which I think makes it more susceptible to this kind of problem - and on the tree surgeon's advice, out it came.

4) An arbutus unedo, again planted by me and a lovely healthy tree - but I planted it too near the patio, so it was overshadowing that and indeed my neighbours' too, so at their request out it came (they are lovely neighbours who have been here even longer than me so I didnt mind keeping them happy).

5) Which leaves us with my holly tree - Handsworth New Silver, planted 30 years or more ago now. Strictly speaking much too near the fence, as you can see below (sorry about quality of the second photo, taken through the bedroom window). Problem overcome by cutting off the lower branches but leaving the upper ones free to do their thing. I love the way it looks and fortunately my neighbours (the other ones) don't object to it overhanging their garden a bit. You can see they have an Irish Yew pretty near the fence themselves. But if they did mind, out it would have to come - and I would thank it for the pleasure it has given me over the years, and view it as an opportunity to do something fresh in that space.

6) Finally, I put in a new crab apple last autumn - you can't see it in the photos but it is in the border opposite to the holly. It is called Jelly King and is meant to stay relatively small - fingers crossed!

 

The biggest issue you will have will be that of "overhanging" - any branches which overhang your neighbours garden they have the right to chop off. By doing that, it will alter the shape of your tree plus, if not done properly, or at the right time, could introduce disease into your tree.
Also, if the predicted width is 4m its likely the roots could spread equally as far. Your neighbour might even decide to chop your roots out (on their side) which could destabilise your tree.

I have an Amelanchier lamarckii next to my fence but, I keep that in a large pot.

The real question is:

How much spread after 30/40/50 years?

Sorbus commixta 'Embley'
(Ultimate height: 8-12mtrs, ultimate spread: 4-8mtrs: Time to ultimate height: 20-50yrs)

Amelanchier × grandiflora 'Ballerina'
(Ultimate height: 4-8mtrs; ultimate spread: 4-8mtrs: Time to ultimate height: 10-20yrs)

So, it seems they could reach as much as 8mtrs in spread; on that basis, 1m from the fence could be pushing it.

May I ask the purpose of them? Are they to give some privacy from over looking windows?

 

Larkstar, an arm's length IS too near the fence. Two metres better esp if pruned now and then.
The amelanchier for me needs more space to display its shape elegantly.
Yes, a mahonia planted by a front door was a big mistake, a eucalyptis gunnii planted 6' from the house an error, but I see so many like this. A ceanothus Trewithen Blue too near a wall and another ceanothus planted in a friend's garden had grown into the guttering and damaged roof tiles.....this sold as a medium size shrub.
Coincidentally I have Ilex Handsworth New Silver planted near a wall.....2 metres I would say. It is 3 metres tall and 2 metres across and pruned to shape annually. An even bigger holly, Golden King, is similarly planted 2 metres from the wall and is a nice feature all year round.
Remember, most trees continue to grow.....no such thing really as a dwarf tree.....and, in my experience, grow much faster than expected to.
If in doubt allow a little more room Larkstar

 

@larkstar excellent thread ... Asking for info something we all need to do before planting Trees so hats off to you ....Hmmmm how many have made these innocent rooky planting mistakes ..more than we can shake a stick at im sure but very few will admit to it but we all know it happens

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@Clare G for such in-depth information, clarity and above all honesty in your what you have considered failings ...how refreshing to us mere mortal gardeners BTW i think your Holly is superb ...i do hope your neighbours continue to like it too ...and whilst on the subject of neighbors what a first-rate considerate neighbor you are ..I don't have neighbours only wildlife...but if i ever have too ...im taking you with me to be my neighbour... Not only considerate to a fault ...an animal lover ...with a BEEutiful garden too boot... Jackpot

@"M" as always love reading your posts full of sound advice and pertinent questions .. that open up even more friendly useful informative posts .....unlike me dizzy bizzy BEE