It sounds like you are seeing winter damage on your plant. You should probably wait and see if the plant returns to more robust health, and to see if new growth develops where those leaves have dropped before deciding whether to prune it at all. The local web site Great Plant Picks indicates that Arbutus unedo can be cold-sensitive. Arbutus unedo 'Compacta' tolerates a wide variety of soil conditions. It grows best in part or full sun and is drought tolerant once established. There are few insect and disease problems, though it can occasionally get aphids and there may be fungal spotting on older leaves if grown in very poor soil. Foliage and flowers may be damaged in extremely cold winters. If you think that there is something else going on besides winter injury, I would recommend taking a sample to a Master Gardener Clinic for diagnosis.

Below are some suggestions from aWSU Extension article:

What to Do for Winter-Injured Plants

1. Don't do anything until late spring when new growth begins on the live wood and does not begin on the dead wood. Then prune to remove dead wood. Before doing anything, check to be sure the crown is alive.
2. Prune properly. Do not leave stubs. Prune back to live, green, healthy wood. Prune to a bud, stem or trunk. Give a suffering plant a chance to become healthy again. Prune out only dead and severely damaged wood. Do not prune live wood. The larger the leaf surface area of the plant, the better it can manufacture food and grow new tissues.
3. Water properly. Make sure the plant is not further damaged by drought. Pay special attention to evergreens and plants situated under eaves. Water properly throughout the spring, summer and fall. Do not overwater. (See EB1090, Watering Home Gardens and Landscape Plants, available at your WSU county extension office).
4. Fertilize properly. Fertilization is recommended if the soil lacks adequate amounts of basic plant nutrients.
5. Mulch with a loose organic mulch to maintain soil moisture and protect from temperature extremes.
6. On damaged fruit trees, remove as much of the developing fruit as possible to allow it to overcome the winter injury rather than produce fruit.
7. The best thing you can do for your injured tree or shrub is to avoid further stress during the coming season by giving it special attention and care.

Season All Season
Date 2007-04-13
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According to The American Horticultural Society's Pruning & Training edited by Christopher Brickell (DK Publishing, 1996), you can prune Arbutus unedo in spring, as soon as danger of frost is past (that would be early April in Seattle), but keep pruning to a minimum. Some people choose to remove lower branches to create a taller trunk on younger trees.

The book Pruning: A Practical Guide by Peter McHoy (Abbeville Press, 1993) says that Osmanthus decorus can be clipped in late summer. If you want to limit its size without clipping, prune back long shoots to points far inside the shrub in late spring or early summer, after flowering. If the plant is overgrown, you can spread this type of pruning over two or three years, but do not do it annually. I am not familiar with this species of Osmanthus, but I do know Osmanthus delavayi, and grow it as a hedge. It is sheared after it flowers, and then probably two more times before winter. I did have to prune the top back quite hard last year, and this did not seem to cause any problems, but O. decorus may have different needs.

I could not find information about Viburnum odoratissimum specifically, but most pruning books have general guidelines for Viburnum species. Unless you do not mind losing the flowers, it is best to prune when flowering is done. If you are growing V. odoratissimum as a tree, then special pruning may be needed. George E. Brown's The Pruning of Trees, Shrubs and Conifers (Timber Press, 2004) says V. odoratissimum is somewhat tender, and may grow best as a standing bush with the protection of a wall, using ties in places to keep it close to the wall. The only pruning he mentions is cutting out older wood after flowering, and tying new growth back to the wall (if you are growing your plant in a site where you can do this).

According to the Peter McHoy book, oaks do not require routine pruning. Brown's book says not to prune oaks between mid-spring and mid-summer, as a means of protecting against oak wilt and beetle infestation. If you must prune, do it in winter.

Quercus reticulata is not a common tree, nor are the species of Viburnum and Osmanthus you are growing. Unless there are compelling reasons to prune harder, I would suggest sticking to the 3 D's of pruning: take out only dead, diseased, and disordered branches. Another general rule of thumb is never to remove more than 1/3 of the plant at one time. You might want to consult a certified arborist as well. You can find arborists through Plant Amnesty's referral service or the Pacific Northwest Chapter of the International Society of Arboriculture.

Season All Season
Date 2008-03-19
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I am not familiar with the size and shape of propane tanks, but perhaps evergreen shrubs might work to screen them. A concern would be the proximity to the house, and any needed clearance for paths, doorways, and windows. I think you are right to avoid Wisteria. Does your friend prefer the idea of planting vines, or would shrubs be acceptable?

Here are a few suggestions for evergreen shrubs, with links from the local web site, Great Plant Picks:

• Arbutus unedo 'Compacta'
• Ceanothus
• Morella californica
• Osmanthus delavayi
• Viburnum tinus

Some good information is also available about plants for screening and vines, especially evergreen vines such as Trachelospermum jasminoides, which might be a good solution. Local garden writer Valerie Easton on has written helpfully about hedges, as well.

Season All Season
Date 2008-04-16
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Sunset Western Garden Book (2007 edition) has a list of wind-resistant plants. From that list, there were a few plants which meet some of your site's needs (evergreen, fast-growing, about 7-10 feet tall). They are:

• Arbutus unedo (Strawberry tree)
• Arctostaphylos (Manzanita)
• Ceanothus
• Chamaecyparis
• Cotoneaster
• Escallonia
• Morella californica
• Pinus species (you would need a dwarf pine for your size limits)
• Pittosporum (many of these grow taller than 10 feet over time, but P. tobira might work)
• Pyracantha

I don't know if it is tolerant of winter winds, but Osmanthus delavayi makes a nice, dense evergreen hedge with flowers, and reaches about 8 feet. It grows fairly quickly also.

Two good resources for finding more information on the plants above are Oregon State University's Landscape Plants and Great Plant Picks.

Also, I found an article on wind tolerance from Colorado State University Extension which may be of interest. Here is an excerpt about the physical characteristics of wind tolerant plants:

When considering which trees and shrubs do well in windy conditions, examine the shape and thickness of the leaves, stems and branches. Wind-resistant trees usually have flexible, wide spreading, strong branches and low centers of gravity. Wind tolerant shrubs often have small, thick or waxy leaves or very narrow leaves (or needles), to help control moisture loss. Plant species that have large, flat leaves "catch" wind. These plants have a tendency for branch breakage when strong gusts blow, or if laden with heavy, wet snow. Evergreen (conifer) trees are an excellent choice, having needles and being flexible in high winds.

Season All Season
Date 2008-04-30
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