My weigelia was hurt by late freezing temperatures in early spring and did not bloom as normal and has a lot of dead branches. It does not look healthy and I want to know if I can cut the entire shrub back to approximately 1-2' and let it start over. If so, when should I do this?
The best time to do rejuvenation pruning is while the plant is dormant in late winter. Avoid allowing the plant to use up a lot of energy to leaf out and then cut it down. That would be the worst thing you could do. The best time to prune dead, diseased and crossing/rubbing branches is right away regardless of time of year. I often rejuvenate shrubs with a 3 year plan. I remove the 1/3 of the branches to the ground, removing the oldest ones right after the shrub is done blooming. (No later than June 30 for spring-flowering shrubs) Do this for 3 years and you have a new plant and don't have to go through the awkward look of a total cut down. Most blooming shrubs benefit from annual pruning. Old wood doesn't bloom or leaf out as well as young wood. Prune summer-blooming shrubs in early spring.