Answer: Lilacs prefer a loose, well drained and slightly acid soil and should be grown in full sun for best flowering. In my experience adequate fertility also helps ensure top blooming performance. If there is some doubt about the quality of your soil you might wish to run some basic tests and find out for sure about it. Your County Extension (652-3370) should be able to help you with the tests as well as interpreting the results. In my opinion, too, temperature seems to affect the color of the blooms -- a cool spring seems to make them more intense to my eye.
Q&A Library Searching Tips