I believe they would grow to about 15' in maturity. Maybe 20' in their native country. Maybe what you read said to plant 8' apart? The closer you plant them, the narrower they will grow. These are planted as a hedge.

Thanks for the info. I am planting the hornbeams next to a row of Emerald Green Arborvaties. These arbs are planted 4 foot apart. I wanted to plant these hornbeam trees in the gaps to block (neighbor pool).

There are few narrow tall trees out there...may have to go with a hedge..thanks again.

Wow. That's a lot of trees. And those are expensive trees too.
If there's anything I've learned it's that rather than finding a narrow tree to form a green wall, just get a medium or large tree or even a small tree, something that forms a 20-30' canopy when planted 20' apart. They'll grow faster than any arborvitae or hornbeam and their wider canopy will give you the privacy you're looking for with a lot fewer trees, in less time, without taking up as much floor space, won't require as much irrigation, won't look really strange if one of the trees in the row dies.

I don't know how much space you've got to start out with but if you're planting your arbs 4' from the property line, then another 4' to your hornbeams, (they'll remain under 6' wide for several years at least). That's 10' right there. You could use something like yoshino cherry or trident maple or perhaps something even larger. In 5 years time, maybe less, you'd have privacy.

I'd stick with just the Emeralds.
How is your neighbor going to like a lot of leaves in his pool?

Wow. Thanks for the great comments. Like the last comment, maybe stick with just the Emeralds as they should get tall...but this will take years. I forgot to mention that I have a fence, but the yard is not level. So the reason for the arbs and maybe trees.

I have attached a picture looking from the front to back yard. At the bottom of the picture (between arbs and patio) there is about 7 feet across. I was going to plant a Japanese holly skyrocket. I was looking to plant the tree a few feet behind the patio and in front of a sewer line (sewer cleanout is by 2nd to last arb that runs parallel to the right of the arbs). There is ~ 18 feet between the sewer cleanout and patio.

The concern is planting too close to the patio/house and the sewer line. Any ideas? Thanks again for the advise.

Here is a link that might be useful: Looking from the side yard to the back

Hi again. I have attached another picture from back to front. This view may be better. Shows the sewer cleanout and patio. Thanks again!!!!

Here is a link that might be useful: Back to front view

Just as I suspected.
That space in between the patio pad and the fence you could use a single small tree such as hornbeam or smoketree or something like that. Some companion shrubs can be planted around/along with it and against the fence.

10-12' away, you can place another medium to small tree (regular European hornbeam, flowering cherry, yellowwood etc or tall columnar tree (bowhall or karpick red maple -or alternatively armstrong freeman maple if you are out west or in alkaline soils). If you're in a climate that can support it, evergreens like southern or sweetbay magnolia

In between the trees, you can plant some (shade tolerant) larger growing shrubs. Viburnum, holly, you get the idea.

I like arborvitaes but that row of them is going to take a decade before it gives you any screening and it looks like it is too close to the fence. If you are in a heavy snow area you'll need to keep on top of whacking the snow off the arborvitaes.

If I bought your house as it is now, I would (hate to say it) remove the arborvitaes, then remove all the grass and make that whole side a continuous 5-6' bed. Maybe even a berm. Then replant with small and medium (towards the front) densely branched or evergreen trees and larger (towards the rear) shade trees. In between the trees some larger showy shrubs and in front of the trees would go some lower growing evergreen shrubs. And in between that and your larger shrubs you can put in some flowering perennials.

In 5 years time, you'll forget all about the neighbors. By that time you'll probably be ready to move anyway and on your listing you can say you the home has landscaping rather than a privacy hedge that is only about 6' tall and obviously trying to hide something.

Thanks Gardeningrandma for the suggestions!

I planted the arbs 3 feet from the fence and 4 feet apart. Everywhere I read (even on the tag) it said it would get 4 feet wide. So I figured 3 feet away from the fence. Now, you are saying they are too close to the fence? :(

If I decide to keep them where they are, am I going to be OK? When they get bigger, can I trim them to keep the width under control?

I am still learning. I am glad to have found this forum to learn from my mistakes......Thanks again :)

No, 3' is OK. They looked much closer than that to me in the pictures. 4' spacing between the trees on the other hand, is too much spacing to form a solid hedge. What a lot of people do is stagger 2 rows of them but that would be so expensive to do.

When they get bigger, you can trim them but that's quite a bit of maintenance. There's still places they can be used. They're nice in groupings or as specimens. I use them individually to screen the view of things like satelite dishes and garbage cans and they look nice as a corner accent. In your case I'd get really impatient waiting for that to provide any appreciable screening or privacy.

If you choose to leave them, I'd still suggest removing the grass. It will become a pain in the butt to mow around those trees and a mulched strip will be better for the arbs. They get burned easily by drift from lawn weed sprays as well. That can turn an otherwise pretty hedge into a seriously worrisome problem.

European hornbeam is a 60' tree on suitable sites. 'Frans Fontaine' is not dwarf-growing, it just has branches that are sort of bunched up as though somebody was trying to tie it together for transport. Other trees mentioned here are also real trees, eventually filling spaces multiples of 10' wide - and not shrubs less than 10' wide.

You might get some ideas out of the hedges and screening table in the plant selection guide near the front of the Sunset WESTERN GARDEN BOOK (2007, Sunset Publishing, Menlo Park).

You are probably posting from back East somewhere, would not be using WESTERN GARDEN BOOK.

Urban landscapes needn't worry about their trees reaching champion sizes. Especially when they're planted close together like that.

Thanks everyone for the useful information.

I think for now I will leave the trees. I planted these last year around this time and it looks like they have grown at least one foot.

I am planning to get rid of the grass around the arbs. I assume it is best to mulch this area as it keeps in moisture? If I put rock in this area, the sun will beat on the rocks and not be good for the arbs. Is this correct?

Thanks again for the help.

60' is not a champion size for that species. Far too many plantings contain large-growing trees and shrubs planted for quick or temporary effect, to soon become liabilities or mal-pruned eyesores.

I understand that bboy but what do you suggest then? Planting the aborviteas 30 feet apart? I have never seen an arb that big. That may be common in the northwest where absolutely everything grows like mad and the weather is always moderate.

belilly, yes natural mulch (wood chips for instance) are good, rocks and rubber mulch not good.

Thanks Gardningrandma. The mulch will be my next project. Do I need to kill the grass that is there before I do anything? Like put plastic down over the grass and over some time it will die? What do you recommend?

Thanks again for the help. I agree it will look much better and is better for the arbs. I was thinking about getting a soaker hose too leaving it there in the mulch.

What kind of grass is it?

not certain why others have reported that you should move your emerald green arbs.

They should not spread to much into your fence since the fence will block some of the light and that side of the arbs will reduce their growth because of the decreased light. Also the 4 foot spacing apart gaps should not be a problem; especially if you plant a row of Frans Fontaine Hornbeam in front of the arbs. but stagger the Frans Fontaine row so that the planting hole centers for them in that row are centered and infront of the spacing between the planting hole centers of your Arbs

The Frans Fontaine stay very narrow, in fact; by the time the Fastigia Hornbeams have lost their narrow shape and have begun to spread fairly wide, your Frons Fontaine Horbeams will still be remaining narrow enough to avoid making your screen planting appear overgrown.

One other thing I am confused about is the advice given suggesting you could save money by planting wider spreading and faster growing trees and shrubs. Seems to me that would be a big mistake for your narrow strip of planting area, Such plantings would only serve to over grow your area and become an eyesore that would ultimately need to be removed.

One other thing you should consider is the fact that your arbs are very easily killed by bagworms. Especially in zone 8 during the hot summer months when the arbs are slowing down a bit in growth just to maintain against the hotter and drier conditions. I usually do not like to use system bug killer products, but I have found that if I do not use the Bayer systemic bug killer product or some other systemic treatment that is just as effective. my Emerald Green Arbs do not survive, and they end up becoming a good feeding ground for the bagworms to over populate and start massively invading my dwarf Golden globes.

Wow. This is interesting.

Gardeningrandma - the grass is fescue (what is left of it-some is turning to weeds). This will be a project for next spring.

Katrina1 - thanks for your follow-up. I am keeping the arbs. They are great trees. My neighbor just had bag worms on his trees. Not pretty. I have memories as a child picking these things.

Any idea how wide the Frans Fountaine get in 20-30 years? I have read 8 foot, but may be more. If I get these trees, how far should I plant from the arbs? I would plant the frans fountains on the centers.

Thanks again everyone for the help.

The fescue can be killed with non-selective herbicide like roundup but you have to be extremely careful not to get it on the arbs. If you don't want to use chemicals, shoveling it out might be possible. Some people say that you can lay down layers of newspaper and that could kill the grass. I have a hard time believing this will work but haven't tried it personally.

As for franz fontaine, have you seen what price they go for?

Gardningrandma,
I will try and put some dark plastic down to try and kill the grass. I will also try the newspaper and see what happens.

As to the cost of the franz fountaine, one tree is $150. It is about 6-7 feet tall. As for the arbs, they cost $8.50 each and they were 3 feet tall. What is nice about the arbs is that they give year-round privacy. With a tree, the leaves fall off....but by that time pool season is over.

Thanks for your help.

Well I can only lead a horse to water on my planting suggestion but I highly suggest you don't use plastic to kill the grass. Unless you want to sterilize your soil.

Gardingrandma,
I talked to someone at work today about killing the grass and your suggestion was correct. Put 5 layers of newspaper down in each area and weigh it down with mulch. Hopefully, in the fall I can plant the Hornbeams. Thanks again for your help.

You're welcome but for the record, that was not my suggestion. I don't think a several layers of newspaper will kill tall fescue. I think the first rain you get is going to make chop suey out of your newspaper and when it dries out it's going to blow away. That's my prediction but I could be wrong.

In my opinion the Frans Fontaine Hornbeams will be fine if you plant them centered only 3 feet away from the arbs widest potential spread. I say this because it will take more then 10 years before they widen more than even 4 feet and also because you can always, many years later, prune up the hornbeams trunks to be clean for at least the height of your fence. Just remember to keep a one third clean trunk ratio to two third canopy ratio whenever you choose to start doing any raising the canopy pruning on any of your Frans Fontaine hornbeams.

I also am of the opinion that eventually your Frans Fontaine Hornbeams will continue to grow taller even after your Emerald Green arbs begin to signicantly slow down their height growth.

Thanks everyone for your comments. Trees and landscaping are an amazing subject. I will keep the arbs for now and plant some shrubs around them with mulch. In the fall, I will get some hornbeams......Thanks again for your help.