Answer: Spruce do tend to suffer terribly from spider mites; do keep a very close eye on the remaining plant as it may also be infested. In some cases the damage is in fact done during the cooler months and is not apparent until the weather warms up. However, properly timed applications of dormant oil may be effective. Your County Extension (458-5612) might be able to help you with that problem and suggest controls.
Some possible replacements might include other dwarf conifers which appeal to you, since although their ultimate size will probably be too large they do grow slowly. Another option would be a low to medium height juniper assuming there is room for the shrubs to spread outward, or perhaps a denser and smaller form of the mugo pine. You might also consider some of the new varieties of very small spring and summer flowering shrubs such as the pink-flowered spireas, the white or pastel or golden flowering potentillas or the "Miniature Snowflake" mock orange.
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