County Down,
United Kingdom 
Hi all, 3 to 4 years ago I took a cutting/shoot from the root of a Lilac bush from my parents house, as it always reminds me of my youth. I put 3 plants in pots and left them for a year in a poly tunnel until they had apparently taken. I have planted them outside and they seem ok, growing in height to approx. 3 feet but no sign of any flowers, any ideas?
24 May, 2015
Answers
Some don't flower for five or six years so don't give up hope! Three feet isn't very tall for a lilac unless its a dwarf bush type. They would take the whole of the first year at least to make a good root system, and then another year at least to settle into the ground after planting out before they could get down to putting some height on. Its better for them to establish well before using energy in making flowers so be patient!
Sorry Bamboo, we crossed. Lets hope it isn't a wild one as they sucker enthusiastically!
24 May, 2015
Lilacs can also be grafted on to privet rootstock, so you might be growing a privet hedge! Compare the leaves on your plant with those of a lilac to work out which you have.
24 May, 2015
Might be a couple of years or more before you get flowers, but one other point - if the lilac tree in your parents' garden was a particular variety, grafted onto a wild lilac rootstock, and you took a sucker or two from the rootstock, what you'll get is wild lilac and not the cultivar your parents may have had. If it wasn't a grafted tree, then you should get the same plant your parents had.
24 May, 2015