Re: advice on trimming bushes needed

You could be right. But bhg.com said to trim lightly. I like your advice better....

6' is pretty small for a lilac - how has it gotten "out of hand"? Generally, pruning lilacs should occur immediately after blooming so as not to disrupt next year's bloom cycle. Rejuvenation pruning can be done during the dormant season, but a 6' lilac is unlikely to require rejuvenation. How long has it been planted? Most young lilacs take several years to establish and become full. They generate new growth from the base (suckering stems) and that usually takes several years of establishment before occurring. I would not recommend you remove more than a third of it at any one time.

Boxwood doesn't have thorns - perhaps you mean barberry? They can be pruned back hard, but suggest you wait until later in the season to do any extensive pruning. Plants in full growth mode and the heat of summer tend to get over stressed with drastic pruning at this time of year.

pam - gardengal