I have two lilac bushes. This year one had six clumps of blossoms, the other had none. Now, two weeks later, after the purple flowers have dried up and are gone, I have a whole bunch of small white clumps at the ends of the branches. What is this? I do not recall seeing this before.
It looks like you may have some growth from a root stock.
Lilacs sold today are often on grafted stock.
You should prune away any growth at the base of the plant to prevent root stock take over.
when is a good time to spray lilacs or he ground with neem oil? They are about 3 yrs old.
If you LIlac is infested with pests you can treat with Neem Oil at any time.
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/common-lilac-problems.htm
I have a young lilac bush that is about 1 foot tall. This is its 3rd spring. It is spindly on the top and has a loyal of foliage (no flowers) on theach bottom pga the plant. What is the best way to prune it to encourage healthy growth?
It looks like your Lilac is growing out from the roots or root stock.
If this is a grafted Lilac, the shrub growing from the root stock may be another variety then you planted.
Make sure you have selected a planting area with well draining soil and full sun.
This article will help you.
I've read your article on non blooming lilacs and have tried your suggestions. I've had these small 4 ft tall lilacs for 20 yrs and never a bloom! I've tried transplanting suckers and even whole bushes to a sunnier location but the most they get is 4-5 hours of sun, and do not flower. They seem to bloom on every side road, untended and wild. Why can't mine bloom?
Full sun is 6 plus hours of sunlight, a Lilac needs this amount of sunlight and also the correct amount of chill in the winter to flower.
I would suggest a soil test to determine what may be going on in the soil conditions.
Your County Extension Office can help you with a soil test.
Here is a link to help you locate your nearest office.
Why do the leaves on my Lilac bush curl & wrinkle after blooming period ends ?
Many types of powdery mildew only cause vague symptoms, including curled or distorted leaves, long before the characteristic white powdery fungal bodies appear, making early identification tricky. Longer-standing infestations may cause leaves to die and drop early.
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/powdery-mildew-on-lilac-bushes.htm
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/common-lilac-problems.htm
What do lilacs like for food
This article will help you.
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/lilac-plant-fertilizer.htm
I have a number of what I would call "common lilacs," in while, dark purple, and, uh... well,'lilac.' Then I have another bush, a little less vigorous, about 8', smaller flowers, smaller leaves, does NOT sucker. I always thought the smaller bush was a "French Lilac," but now I understand that "French" = "Common." So, what's the little lilac?
There are many types of Lilacs, including Dwarf varieties.
These links will help you.
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/common-lilac-varieties.htm
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/is-lilac-a-tree-or-a-shrub.htm