Answer: Some insects can cause this problem: aphids and tarnished plant bugs are the two that come to mind. If you don't see and pest insects, then perhaps the problem is a viral disease that the 'Better Bush' is resistant to.
To protect the plants from further insect attack, first make sure you've gotten rid of those that are on the plants. If the foliage is truly dried up, the prune it off. Then cover the plants with a fabric row cover (sold by Gardener's Supply Co., 800-863-1700, http://www.gardeners.com, and at many garden centers).
If pests aren't the problem, then send specimens to your agricultural extension service for diagnosis. Call 508-362-2511 to find out where to send a sample. Best of luck to you!
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