I live in South East Tennessee. About 7 years ago I planted two Lilac bushes in my front yard. One is the regular purple kind, the other is called a French Lilac.

The purple one started to get too congested in the middle, so I cut out all the middle branches that looked dead. I also started getting Kudzu growing around it. This year it is doing better.

Lilac Bush

The French Lilac looks like half of it is dead and I don't know what to do. I planted both of these bushes the same year, but one is huge and the other is only half as tall as it was when I planted it. Maybe it is supposed to be that way?

French Lilac

I cut some of the branches down and the sucklings at the bottom. Now what?

It is planted in what became a low spot in my yard after having my yard dug up to have pipes from house to sewer replaced. They just filled in the yard and planted grass seed. It is no longer level. Could it be the drainage?

There is a greenish white spot where the stem meets the tree.

Lilac white spots

  • How do I post my pictures?
    – Juliana
    Apr 17, 2016 at 17:21
  • When you edit your question, there's a row of buttons above the edit window. The 6th one from the left (looks like a little landscape picture) allows you to add photographs.
    – Niall C.
    Apr 17, 2016 at 18:29
  • I tried that. I was able to get one up. When I try to post another, a red thing pops down that says "There was a problem uploading image. Try again?"
    – Juliana
    Apr 17, 2016 at 18:33
  • 1
    I looked at your album of pics - unfortunately, I didn't see what I wanted to see, which is, a picture of both plants from a distance - there is one of a small bush, but not one of the large one. The close ups are difficult to tell apart, not sure what I'm looking at, other than the one with very thick trunks. Precisely which variety of Lilac do you mean when you say French lilac, which appears to mean either a type of smaller lilac or Galega officinalis, which isn't lilac at all. From reading on line, 'french lilacs' vary between 8 and 15 feet in ultimate height.Does the area collect water?
    – Bamboo
    Apr 18, 2016 at 13:52
  • 1
    Yes. It was high ground but now it is low. We keep adding Miracle Grow garden soil every year. Half of the branches have no leaves or anything on them. They look dead. The other half looks great. Leaves have no spotting, buds are about to bloom. When I bought the bush at Lowes, it said "French Lilac" on the tag. The flowers are light pink. I will add pics of the bigger lilac I took last week. I will take more tomorrow. Thankyou.
    – Juliana
    Apr 19, 2016 at 0:35

1 Answer 1


OP appears not to have revisited in just under a year and even some of the images provided at one time are no longer available so to patch together what facts we do have:

  1. Terrain level has been effected by laying of replacement pipe – in particular, the location is now a low spot.
  2. The tree was sold as French Lilac, so is presumably a Syringa vulgaris, since Galega officinalis, which shares the same common name, is a herbaceous plant.
  3. It started getting Kudzu growing around it.
  4. Kudzu seeds will successfully germinate only when soil is persistently soggy for five to seven days.
  5. Kudzu modify the relative pore distribution in soil and hence freeing for plants even more water than in the original soil.
  6. There is a greenish white spot where the stem meets the tree.
  7. In late summer, lilacs can be attacked by powdery mildew, specifically Erysiphe syringae, one of the Erysiphaceae. Also: Microsphaera syringae is a fungus that can cause powdery mildew in lilac. (This is the same taxon as Erysiphe syringae.)
  8. Powdery mildew causes leaves to fall off and the shrub to look unattractive.
  9. Once established, lilacs only require occasional watering.
  10. In the first picture (though not the second) the smaller lilac appears to be partially shaded by the larger.

When there is more rain or humid conditions we see more powdery mildew on our plants. The sudden change from wet or humid conditions to warmer, dry temperatures are perfect conditions for this fungus to grow. Warm temperatures and shady conditions encourage the fungus to grow and spread.

It seems at least plausible that the leaves have been shed in response to an attack of powdery mildew, brought about by an increase in soil humidity, probably attributable to the groundworks for the sewer replacement, and that poor drainage has contributed to poor growth (stunting) of the bush.

Application of Miracle-Gro may be exacerbating matters with the added nitrogen encouraging tender, and more susceptible, leaf growth.

There does not appear to be room within the property boundary for a sump at a lower elevation but one at the same elevation might alleviate the problem.

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