Question
I live close to Memphis, Tennessee, in zone 7a, with heavy clay acid soil. I planted four common (species) lilacs, one purple and three white on the west side of my house in native soil amended with compost. They are doing well, no disease, though the purple one is growing slower then the white ones. They have not bloomed yet. The purple was planted in spring 2007 and the white ones in spring 2008. The white lilacs are 4 feet tall and the purple is three feet tall. The are all mulched and watered when we have dry weather. Is this area too far south to get common lilacs to bloom? How many chill hours do they require? Thank you

Answer
Hello Matthew

Lilacs are puzzling creatures!  - it is said that they don't like acid soil, but mine grows in a fertile, peaty (acid) soil and does very well!

Lilac is not put off by a clay soil, but it does need it to be well drained - a contradiction in terms if ever there was one!

It needs to be in full sun for at least 5-6 hours per day - I guess you don't have a problem with that!

You say that there is no evidence of pests or diseases (lilac is very disease and pest resistant), and, that other than not flowering, your plants seem to be doing well!

So - it may just be that your lilacs are not ready to flower - it can sometimes take 5 or more years before they bloom - sorry about that, but I think this is a case of 'be patient', it will happen!

Gill