Q. I wish to transplant a lilac bush. It is facing west and struggles during the heat of the summer. I believe a better spot is on the north side of a south wall with more shade. I would like to transplant now while it is cool, so I can continue my landscaping. Is this the time?
A. In cooler climates, lilac can be planted in full sun and withstand full sun all day long. You are right, your lilac in our climate will do better in a different location. But if it is too shady, it may not bloom very well, if at all.
Regarding transplanting this time of year, we would like to have some root growth after transplanting. Root growth is very dependent on soil temperature with very little of it occurring when these temperatures drop into the 40’s. It is getting late for that right now and you are moving the plant from a place that has warmer soils than its new home.
Plants are easier to move by hand if they have been in the ground less than three years. It seems to me, that once they hit that three year mark, the root system can be very established and make the plant difficult to move. Plants watered with drip irrigation with emitters close to the trunk are easier to move since most of the roots have restricted growth.
Unless you can be sure that you can take a very large root system with the plant, I would wait to spring. What you can do this time of year which will make moving the plant in the spring more successful, is to root prune now. Take a sharp shovel and slice the root system with this shovel just to the inside of the root ball that you will move in the spring. This will sever the root system, causing its regrowth closer to the plant. Be careful not to cut any drip lines.
This is kind of a judgment call this time of year. It is on the tail end of transplanting season. I hope I have given you enough information to make a decision regarding your situation.
Be careful when you buy lilacs. You have to plant lilacs with a low chilling requirement if you expect them to bloom in our climate. Common lilac may not bloom in the lower elevations of
Southern Nevada because they do not get enough cold during the winter to form flower buds. Low chilling requirement common lilacs such as ‘Lavender Lady’ or ‘Angel White’ will bloom here. You may also want to select Persian or Chinese lilacs instead of common lilacs.