With conifers, grows fast = grows large; you can't have one without the other. If you want something that grows fast and then stops, try bamboo.

Resin

Moist clay and conifers don't mix at all, so you're not going to have much luck anyhow.

Almost reminds me of a property up near Wilsonville, Oregon, that someone from California just acquired. They contacted me about the roadside of 9 acres, where trees will need to line that edge. Seems to be about 900 feet if I remember. Can easily take muliple rows of small or very large trees.

I suspect if you have a bit of width to the strip, that big may be okay.

Sequoia's are superb, but not too fast at first. But can be placed a bit closer than coastal redwood, which I also like alot.

If you can do a staggered continual triangular spacing, that's very practical, but not essential.

Blue atlas cedar is worth checking into.

You could mix several types into areas. If you like what you find online for Arizona Cypress 'Blue Ice', it could be placed a bit closer than the big trees.

Odds are, that 10' spacing trunk to trunk is getting "squeek" but possible. But you would need to do some pruning once they met.

See what you think of Grand fir.

Anyhow, those are some favorites.

M. D. Vaden of Oregon - the tree guy.

"Moist clay and conifers don't mix at all..........."

I'd not place too much stock in this statement. If Lucy had said SOME conifers, it'd be okay, but as her statment stands, well, it's just plain wrong.

I think, for example, the genus Thuja would handle this situation well.

+oM

Moist clay and conifers do mix very well. That's one benefit of living in a major conifer environment like west Oregon, or west Washington. We see first-hand how they grow in many clay soils. We have huge conifer forests here, and many of our soils are clay soils. Not neccesarily dense clay like is found along some flood plains, but it's frequently in the clay range of the soil triangle.

The best recommendation for trees in our region is that soil be kept moist.

If soils are not moist, then we are looking at "permanent wilting point".

There is a big difference between saturated soil and moist soil.

Unless we are growing something like cactus, we need to aim for moist soil for many conifers.

When our Oregon conifers in the clay type soils get extra summer rain, the growth rings get bigger in most cases because they flourish even more, due to the soil being more moist.

M. D. Vaden of Oregon.

I would never try bamboo. Too many horror stories about it spreading, crossing property bounderies, spreading more, lawsuits, etc.

The statement that conifers don't grow well in clays is completely absurd. Maybe there are some that don't but we have lots of conifers in our neighborhood that grow like crazy in our clay soil including Coastal Redwoods, Thuja, and Dawn Redwoods. I'm sure there are more.

I agree that the wet clay and conifers statement doesn't hold up. At least in my experience.

I live in the middle of a moutain valley with pretty good clay 18-24" down. There is water everywhere. I have no basement, just a crawlspace with a sump pump because of the high water table.

Most people here grow various spruce trees. Colorado Blue does particularly well. I am having good success with Frasier fir, grand fir, larches (L. laricania--don't remember common name), eastern white pine, norway spruce, dawn redwoods, and others.

Clumping bamboos are MUCH more mannerly than the running ones. They mostly just do a little expanding as they grow, unlike some of the running ones. If you can mow all around a running bamboo, for at least 20-30', then you can probably keep it in check, otherwise, running water, or a VERY solid and deep metal barrier is the only sure stop.

Lucy, I don't know what you have against clay soils, but trees, and most other plants can grow very well in them. If you are trying to grow things that demand perfect drainage, then I would agree that clay is a very bad soil for THAT plant. Pick your plant for your soil, and not vice versa, and they should grow just fine.

Bamboo is an excellent fast growing screening plant. If it has been selected and planted carefully, there is no reason to be afraid of it. Most of the horror stories associated with bamboo derive from ignorance, improper planting and lack of maintenance. And as dibbit notes, there are many forms of clumping (as opposed to running) bamboo on the market and they do not behave any more aggressively as do most other clump forms of ornamental grass. And one of the big bonuses of bamboo is that they bloom and set seed so infrequently that even the clumping forms are extremely unlikely to spread via self-seeding.

Bamboo is a great choice for your purposes and location and I'd urge you to do some research to become more familiar with these plants before dismissing them out of hand.

As far as what "wet" is, that's why it's important to realize just what kind of clay soil is present, and how wet that wet needs to be.

Because hundreds of thousand of acres of conifers grow in the forest seen in CA, WA and OR, where clay soils are moist and often wet.

M. D. Vaden of Oregon

If I didn't already know that conifers can grow on wet clay, I sure know now! Hehehehe!!

I'd bet any west coast areas having clay soils will have VERY wet clay soil in the next few days! I'm a weather geek too, and that's some impressive stuff happening out there. I've seen reports of as much as 10 feet of snow possible for the high Sierras!

+oM

I'd be careful about any type of redwood in your area.

Why not go to a local arboretum or even a good city park and see what is healthy and meets your needs?

Ever consider Italian Cypress? They are a wonderful screen and seem to tolerate just about anything.

Rolf