Knowledgebase
What is the problem with my dwarf Korean lilac bushes? #201992
Asked July 24, 2014, 12:01 PM EDT
I have three dwarf Korean lilac bushes that are about 10 years old. They were originally planted next to each other. Two years ago I had them transplanted to three different locations. Last year they seemed to being doing OK, but this year they seem straggly and have many bare branches. I know we had a hard winter, but I wonder if something else is going on.
What should I do with the bushes? Should I just remove the dead branches which would leave them with a horrible shape, or can I do a drastic pruning to the entire bush cutting everything down to several inches above the ground? Or are they beyond saving and will need to be removed?
I am sending a picture of each of the three bushes which were taken around 11:30 a.m. The first bush faces west but is sheltered from the sun until early afternoon by a deck. The second bush faces east and has a tree adjacent to it that puts the right side of the bush in shade for large portion of the day. The third bush faces south and gets full sun.
Hamilton County Ohio
Expert Response
Thank you for sending the pictures to eXtension.
I don't see any specific insect or disease problems on these lilacs, which leads me to think we're dealing with transplant problems. Ten-year-old shrubs (or 8-year-old shrubs) are difficult to transplant successfully. By this point, they have a wide spread of feeder roots that the plant needs for survival. Unless you had some professionals with equipment help you move them, you may have lost a significant amount of the fine feeder roots. The shrubs were probably surviving off stored carbohydrates last year, and between running out of stored food and having to survive the severe winter, they just didn't have enough reserves to fully leaf out this year.
I would not do any severe pruning this year or next. Remove any dead or near-dead branches because they aren't benefiting the plant. Keep the shrubs watered with 1 inch of rain or irrigation per week.
Don't fertilize the plants! If you've already fertilized, there is nothing we can do about that. But don't fertilize again until next spring. Most fertilizers for shrubs are high in nitrogen, which stimulates leaf growth. But we don't have leaf growth because (I believe) we don't have enough roots. If you do fertilize, use something that has high phosphorus levels (a high middle number on the bag of fertilizer). This will stimulate root growth.
