Why would your lilac bushes have some leaves that are stunted and turning yellow?

== == * You've either let the rose bush get too dry or over watered it. Also check on the back of the leaves (also in the rose pedals) for bugs. If you have any insects on the bush then use 'Safer's Bar Soap' use a potato peeler and put the pieces in a spray water and add tepid water, then spray your rose bushes (all of them or any other plants around them) including the group at the bottom of the plants. Safe Soap is environmentally friendly and it's been used for years. * Yellow leaves are caused by many different factors: too dry, too wet, insects, disease, lack of Nitrogen, lack of air, too much sun, not enough sun just to list a few. Insufficient amounts of Nitrogen can also cause leaves to yellow. If this is the case, water rose bush well. four or so hours later, when roots are actively "drinking" water with Rose Food (fertilizer) following concentration directions on package.