We are here in Hamilton Ontario close to Toronto Ontario.
We had an ornament Korean Lilac tree but it was topped up last year from the snow storm. we removed the tree left the stump, however this summer right from the tree stump we got an weird looking plant or shrub . Please help to identified the plant. Thank you
Thank-you for contacting Toronto Master Gardeners with your question.
Because your attached photo is not clear, it is difficult to be absolutely certain with this identification. The most likely answer is that you have new Korean lilac (Syringa meyeri ‘Palibin’) growth emerging from the stump of the shrub you cut down. You may have observed that the leaves do not look like the ones on your old shrub. They may be considerably larger. This is normal for leaves growing on new shoots (watersprouts or suckers). You will not have seen any flowers this year because lilacs flower on wood grown in the previous year and all of your stems are new this year.
If your Korean lilac was a grafted plant, however, the situation is different. Korean lilacs are often sold as miniature trees, with a single tall trunk and a rounded top. These plants are invariably formed by grafting a Korean lilac top onto the trunk and rootstock of a different species. The stock can be another type of lilac, or, it can be a totally different plant from the same family as the lilac, Oleaceae. Privet (Ligustrum ovalifolium) and green ash (Fraxinus pennsylvanica) are often used as rootstock for lilac grafts. If this was the case with your plant, the new growth you are seeing emerging from the base of the old plant could very well be a different kind of lilac or even a completely different plant – not a lilac at all!
Assuming you would like to regrow your old shrub, the best thing to do is to proceed as if you were working on a renovation pruning of the shrub. This is when a shrub is intentionally cut back close to the ground so that it renews itself from the ground up. Your situation is similar. The links below will take you to articles that describe how to prune your renovated shrub so that it develops a good shape and healthy structure. You may get some flowers next year, but full flowering will likely take a couple of years. This, of course, assumes that your new sprouts are Korean lilac. If they are from a different rootstock, you will probably want to cut them back to the ground and/or remove the old stump and roots.
https://www.finegardening.com/article/pruning-lilacs
Good luck on renovating your shrub!