Looking for a particular type of hedge but I'm clueless :(

Good morning all I hope you are well,

It's my first post here and hopefully I don't make a fool of myself.

I am scouring the internet for a hedge/privacy screen type small(ish) tree that :

1. Has non invasive roots
2. Doesn't drop leaves
3. Will grow up to 10 foot
4. Ideally can be planted in a planter roughly 900mm below ground, 400mm away from the wall and the length would be approximately 10 meters.
5. Won't cost me an arm and a leg
6. I can comfortably keep it at around 300-400mm thickness.

I'm going to explain further and hopefully someone may have a suggestion for me.

I have a 1500mm high wall between me and my neighbour. I'm wanting to build a 400mm planter along the face of the wall and plant trees that will grow into each other and act as a privacy screen.

I can't risk the roots pushing the wall over and i can't really afford for the bush/hedge to grow more than 600mm outwards because I need to get my car past but I'm aware this will be more of an trimming/upkeep process rather than hoping a plant/tree will just stop growing.

I am currently looking at Thuja occidentalis Brabant. From my understanding they can be planted 600mm apart and will grow into an excellent privacy screen. My issue is I can't find any information anywhere as to whether they will survive in a 400mm planter or whether they have invasive roots?

Thank you to anyone that has took the time to read my post

 

Hi, I maybe being thick but slightly struggling as to what you are trying to achieve. Could you possibly put up some photos of the area? Presumably the idea to bury the planter is to restrict the roots of any trees planted? This could cause issues with both drainage and necessitate a lot of watering in dry periods. All conifers do need quite a lot of consistent pruning to keep in check and while Thuja has been known to respond to being pruned into brown wood it is very slow to recover if at all.
I have many, regrettably, conifer trees and hedges, there were many more when we moved here but could only get rid of some without totally destroying the garden.
You will gather from the above that I am not a fan of most conifers as unlike deciduous varieties of hedging they cannot be left for long spells and then pruned back to a required size.
Have a think about the privacy angle. Is it really desired 24/7 or mostly in the spring summer months when a deciduous hedge would do the job? Clearing up leaves of a deciduous hedge is way less work than keeping a conifer hedge in bounds. Also to trim a conifer hedge to look good is quite a skilled job. I have a petrol Sthil hedge trimmer and can make a horlicks of trimming if not careful. I have a beech hedging which is so easy to manage in comparison. It keeps its leaves ( have gone brown admittedly) for a good majority of the winter, not expensive to buy bare rooted. Can be pruned hard if necessary and relatively fast growing once it gets going. I am not sure about the roots or whether it would cope being restricted in a planter. One conifer I strongly suggest you do not plant and that is Cupressus Leylandi. Personally I think it should be illegal to plant it. Causes untold amounts of disputes between neighbours as it can get out of hand very quickly.

 

I note your thanks for reading your post- I have now read it 3 times and am still not fully understanding. Who owns the wall ?
You do not mention the aspect of the wall. You do not explain why you need a privacy barrier ten feet tall. Most neighbours would object to this. You do not state the length required; this will significantly affect the cost.
Would not a trellis topping the wall, planted with an evergreen* climber(s) give the effect without needing to be deep or jeopardising the wall foundations
*such as :
Lonicera Copper Beauty Evergreen Honeysuckle Climbing Plant

 

A fence comes to mind.

 

I wouldn't put hedging plants in a planter. They will not be happy long-term. If you put them in the ground, yes, the roots will grow outwards and not respect property boundaries, but that is perfectly normal. Almost every garden across the land has roots coming under boundaries. This only matters if you plant something invasive like bamboo, which would pop up on your neighbour's side above ground.

I would go for a shrub like Lonicera Baggesen's Gold. Evergreen, copes with drought, can be pruned at any time and kept in the shape you want. It will shed the odd tiny leaf, but very little compared to other plants.

 

Only reservations I would have is I cant see it staying upright at 10ft tall and only just over a foot thick.
I cant think of anything living that can do that.

 

It is certainly not the shape it would adopt left to its own devices, but I have seen it as a screen hedge at about 8' tall and trimmed to be narrow.

 

If you own the wall, fasten posts to the wall, then add fencing upward above the height of the wall.
The image below may be a little OTT insofar as the posts needn't extend all the way down to the ground, half way would do it.

You could then grow something over it like an ivy, clematis or Boston Ivy (Vine)

 

I'm slightly confused [no change there] by the 'planter roughly 900mm below ground' @Jj91. I take it that the neighbouring property's ground level is higher - or am I totally misunderstanding?
Re the 400mm measurement - is that depth or height or both?
A decent sized planter, filled with the appropriate medium, and with decent drainage, will sustain a hedge no problem. The aforementioned Loniceras will be fine, and so would Beech or Hornbeam, which can be kept very narrow and tight. You could even use good old privet. L. B's Gold will certainly get to a decent height in the right conditions.
As to cost, we're approaching bare root season, and that means getting hedging plants at a very good price as they come bare root rather than potted.
The important things though, are the volume of the container and what you fill it with. Then it comes down to how well you establish and maintain it from then on.
Photos will definitely help us to envisage the site properly, and therefore give more targeted advice.

All plants drop leaves though - including evergreens. That's just how it is. Nothing is no maintenance, even if it's low maintenance.

 

In my experience, Lonicera BG gets very unhappy in a container. Even a large pot would only be OK for about 5 yrs max (assuming you started with a tiddler plant under a foot tall. They grow fast and love to be free.