You can prune it, it won't bother next years flowers.

those are seeds from this years flowers ...

they erupted from old wood.. last years growth ...

other places.. you will find lush growth.. occurring since the flowers.. other branches..

if not now.. a little later in the summer.. those will finish elongating.. and form minuscule buds for next year ..

i just hacked a 15 foot high.. by 12 foot wide plant down to 4 foot [by removing all branches bigger than one inch wide.. as close to the ground as i can get]... i dont care about next years flowers .. it was taking over the driveway .. it will be back.. the following year.. with a vengeance ...

do you know how to PROPERLY rejuvenate a flowering shrub???

ken

I don't know how to rejuvenate it
how do you do that?

{{gwi:263180}}

you can tell it is in too much shade... from the tree casting the shadow .. and by the fact that it is lusher way up .. as compared to below ....

hit the link.. and review some of those articles on RENOVATING A LILAC ...

and then.. if you have more specific questions.. feel free to come back.. and if you do.. have a better picture of the entire ground and the first 3 feet of the bush ... and we might help you select which to remove in toto ..

but that will not fix the shade problem ... how many hours of full sunlight will it get when reduced in size????

this is very common.. where trees and shrubs.. 20. 30.. years ago.. were planted and co-existed nicely ... and then as the tree takes over and gives its wonderful shade .... the shrubs start to decline ...

ken

Here is a link that might be useful: link

I was given this little cutting from a friend, it had sweet smelling blossoms when he gave it to me, is it Lilacs? I can't post a pic because I can't access my account. But they are small buds and they are all over the plant. They look like the first pic but not as long yet.