Answer: Yes you can transplant it...it won't be easy, but it certainly isn't impossible. You can do it now, or, in the fall. Basically, a shrub can be transplanted any time of year the ground isn't frozen, but spring and fall are the best. Remember that after it is in it's new spot it may "pout" a bit, usually in the form of not blooming for a season or two. Because the shrub is so old, she may be even more offended than most! All you really need to do is go out to the drip line of the shrub and cut out a circle with a spade or a shovel that goes all the way around. You will want to dig out this ENTIRE bit. The more of the rootball you get, the better chances of survival the lilac has. Plan to do this on an overcast day if possible. Hot sun and wind would be traumatic to the tender roots. Have the new site already dug and ready for the new tenant, though don't dig it more than 24 hours in advance. After transplanting, it is very, very important to keep on top of watering, especially for the first two season. Inadequate watering for recent transplants is one of the biggest causes of failure. You may also want to treat the lilac to a top dressing of organic matter such as compost, leaf mould, or composted cow manure - mulch style, about 1-2" thick after transplanting. This will help her to "feel better". Good Luck!
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