Your picture does not appear. But, it sounds as though a row or scattering of the very easy care, evergreen shrub, Viburnum tinus, would solve your problem. It is happy growing in damp situations. Very attractive shrub. White blossoms during the winter, early spring. Should be easily available in your local nurseries or on line. A fast grower which should survive wind and your sun/shade conditions.

If you want more trees, an alder, cottonwood, or elderberry should do fine in the middle of very wet clay. They grow in swamps all the time.

For smaller plants, I'd recommend lobelias. They're gorgeous, and you have perfect conditions for them.

I can see your picture and you've offered a poser. Looks like the neighbor put trellising on their deck side facing you to afford them some privacy. I'd worry that any large tree with a shielding canopy would (1) eat your yard and (2) encroach on the neighbor.

A somewhat similar thread "Suggestions for trees along tall privacy fence" with last reply on Nov. 3 which has now rolled to page 2, might give you an idea or two. Here, the poster wanted screening height without sacrificing yard.

Tall and skinny and evergreen(s) in your planter and on either side of it could provide a psychological barrier without being a complete screen. Anything planted at the edge of your patio could make that space more private, but wouldn't address the issue of privacy in the yard beyond that edge.

I wouldn't rely on Laurustinus for a permanent screen on soggy ground, where icy winds blow. It is a Mediterranean climate shrub. Broad-leaved evergreens tend to avoid low damp areas, in fact, except for salal growing on old stumps in swamps (where their roots are not in the soggy ground) the native species belonging to this category tend to indicate the presence of well-drained spots.

Since I have seen the frequently planted Pacific wax myrtle apparently thriving on a sopping wet bank at the government locks in Seattle, it seems this might be a possibility for you - as long as the cold is not too severe there. Perhaps one of the hardy evergreen forms of sweetbay magnolia currently on the market could be of use. Otherwise, the main category of broadleaf evergreens for damp ground is the hardy bamboos. As long as it is not actually puddling around them for long periods these love moist soils. I have gotten excellent growth from Fargesia robusta on a clay slope, above a pond in Island County, WA. Like others in the same genus this species forms tight clumps, never popping up where unexpected.

I had thought about some sort of bamboo as the planter will contain it, but I didn't know how it would do in the wind.

I am thinking something like a pergola with a lattice background where some type of climber could be planted on the neighbor's side of it and that would provide privacy and shade in summer. In winter you could have a firepit in there or chiminea. The raised planter would have to be planted with things that would tolerate the new conditions under the pergola. However, depending on how the pergola is built, it could have just a little or alot of shade. A firepit could be placed within the planter or elsewhere, or even a small one brought out in winter with some seating, even on small boulders. Good luck this is a challenging problem but I'm sure a creative solution can be found.

You don't need to contain Fargesia or other hardy clumping bamboos unless there is a reason to keep them in a narrow strip or other unnatural shape. Some kinds will otherwise get several yards or more across, when doing well and with many years behind them. Although there is some variation from one species to another the general mode is a tight clump of slender stems, produced by creeping root-stocks resembling those of irises.

I'd take a bit different approach and redo the entire backyard, getting rid of the raised planters which look very arbitrary in their design and placement and excuse me for saying so, but very amateurish as well. Heavy clay soils are very common in the PNW and relatively easy to fix or at least work with. Get rid of the sand/gravel, get rid of the raised beds and import some good compost to work into the soil. Make a few easy mounds along the perimeter - longish, irregularly shaped berms, maybe 12" in height. Slope gently back to ground level at the fenceline. This will give you some additional height for any screening plantings (you can easily move and relocate the few existing plants), plus it will work to improve drainage or at least provide a fast draining planting base.

I'd disagree about the Viburnum tinus, also. That back garden is pretty restricted and with the fence, should provide more than adequate protection from winds for Laurustinus, provided you are truly a zone 8 (specific location?). I'd hesitate to add any trees in such a tight situation, but some very columnar evergreens could work (i.e. Chamaecyparis nootkatensis 'Green Arrow', 'Van den Akker' or 'Strictly Weeping'). Bamboo could work also but IMO tends to provide much more of a mass than such a small space warrants.

Add back the paver pathway if you like and fill in with lower plantings of your choice and groundcovers.

btw, your willow "tree" is just a shrub form of Japanese willow grafted onto a standard......it will never get much taller than it is now except for some expansion of the canopy.

Am now able to view your picture. You certainly do have a great need for privacy. That planter looks as though it is firmly cemented in. Too bad that you cannot take it apart and use it in another manner. If possible, that would be my first suggestion.

If I understand your plan, you want to plant 'something' that is evergreen in the planter that will provide privacy. Also, you need a large shrub that lends itself to tight pruning. The Viburnum tinus I mentioned above should grow in that situation and adapts well to shaping. An even better shrub is the rapid growing Holly Osmanthus (Osmanthus heterophyllus). You and your neighbor will love this one for its heavenly early summer fragrance. You can keep it in bounds with pruning at any height between 6'-12' and just one will give you the height and width you need for privacy. This shrub is dense growing and will withstand wind. You would have to give your neighbor permission to prune any part that encroaches on their deck. But they should be pleased with this choice. Generally carried by most nurseries. Both shrubs will also grow in a damp situation if planted in the ground.

the well known Laurestinus from the Mediterranean region, is an indispensable shrub. It is variable in size, foliage pattern, and general habit of growth. The type is a large shrub, often more than 10 feet tall and equally broad, rarely 15 to 20 feet. Like so many other shrubs from the Mediterranean region, it frequently suffers in gardens from excessive watering during the summer months. Given a light, warm, well-drained soil in full sun, and its growth ripened during the latter part of the summer, it is hardy throughout the region. When allowed to make soft lush growth, especially in moisture-retentive soils, it may be cut back or even killed outright in severe winters

--Grant/Grant, Trees and Shrubs for Pacific Northwest Gardens (1943, Nourse Publishing, San Carlos)

Osmanthus heterophyllus is slow-growing, like rhododendrons and many other broad-leaved evergreen shrubs. When stimulated to grow more rapidly than normal for it, as under wholesale nursery production conditions, such growth is apt to be sparsely furnished (at first) and sinuous.

I love some of the ideas...also some of the admonishments of the planters and pea gravel. I omitted the fact that we have planted so many things that have drowned in our yard (including grass - two seasons in a row). We have only had luck with willows, a redosier dogwood, and a snowberry bush. All else was put in planters so that we could grow something. Also, we have two pugs that get into/tear up just about anything, so whatever goes into the ground/planters must be non-toxic.

Are you looking out of your house in this photo? If so, I wonder whether the privacy issue encompasses some privacy for windows as well as for the yard? For that reason I think shrubbery is far too small a solution, and I would think about a big tree. Obviously it won't get big all that quickly, and some fast-growing shrubs around the perimeter (in the planter for extra height) would be good in the short term with a plan to cull them when the tree canopy provides some cover. It sounds a bit outrageous, but I think I would plant a spreading tree smack in the middle of your yard. Thirty feet allows for a nice canopy. And even a deciduous tree provides a bit of screening in winter. And of course you'll have leaf debris to deal with so that sand surface might not be ideal.

KarinL

Vine maple is good for summer screening and grows well on moist soils. You can buy comparatively large and inexpensive wild-collected specimens at local outlets, making immediate effect possible without as large an investment as would be the case with nursery-grown stock of the same size.