Holly Shrubs Have black leaves

10 years ago

I did a few searches that said to hit the leaves with a hose sprayer and that this condition was a sign of aphids. I was able to wash off alot of the black stuff but I found no evidence of aphids. We had a bit of a cold snap a week or so ago, I wonder if the cold was enough to kill off the bugs leaving me with the black stuff or does anyone have another idea?

I plan on going over the leaves a few more times to get as much of the stuff off them as possible.

I suppose I could spray a bug killer like I use on my roses (located about 10 feet from the holly hedge) but the stuff is expensive and it is quite a large hedge and would no doubt take a lot of bug killer to do the job.

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Comments (6)

ken_adrian Adrian MI cold Z5
10 years ago
if you see no bugs.. do NOT use bug spray.. that is the definition of pollution ...

w/o a pic.. its hard to go anywhere ...

i would have asked about frost/freeze.. but that kind of damage does not wash off ...

aphids excrete honeydew... which ants harvest.. [if you ponder that too long.. its really disgusting.. lol] ...what is left can turn black ... but that is more of a later summer thing.. rather than early spring.. up my way, anyway ... perhaps it is left from last year.. which means the aphids are long gone ... and its the ants that usually catch my attention.. to find the aphids ....

a pic would sure get us further ....

btw.. if its a mold or mildew... do NOT spray them down near nightfall... as they grow in the dark.. insure your plant goes into dark, dry ... or at least dont wet them ....

and finally.. other than the color.. do you see any detriment to the plant???? .. is it lacking vigor????

ken
flora_uk
10 years ago
If the black washes off it is likely black mould growing on the honeydew secreted by aphids, as ken says. Are there any trees above the holly, especially lindens or sycamores? Both attract aphids and can drip honeydew on anything below. A picture would really help.
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gardengal48 (PNW Z8/9)
10 years ago
The evidence of the sooty mold indicates there were aphids (or other sucking insects) present in that vicinity but the mold doesn't happen overnight. It most likely developed from last season's insect occupation.

You do want to keep an eye on the area, however. If there were aphids present last season, they could well return this season. And it doesn't have to be just aphids - scale and whiteflies also create honeydew and the conditions for sooty mold growth.
rhizo_1 (North AL) zone 7
10 years ago
Scale insects are more common on holly than aphids.
bogey123
Original Author
10 years ago
Sorry can't post a picture, my digital camera is down. The black completely covers the top of the leaves but you can rub it off it is like a sticky substance. The hose takes most of it off for the most part. The hedge has not put out its usual push of new foliage this spring and appears stressed with some appearance of yellow leaves here and there.

I intend to give it a fertilizer boost and keep it well hydrated and continue to work on getting that black stuff off as best I can. In terms of fertilizer I was planning on using miracle grow as it feeds through the leaves as well as the roots and is fairly gentle. Anyone see that being a problem or have a better idea?

My hedge in the front yard which is of the same holly plant is lush and full of new growth. I suspect the black stuff is holding the plant's photosyhnthisis back thus the yellow leaves.

Still no sign of aphids, it is possible this condition happened late last summer / fall and I didn't notice it as I was dealing with some very sick family members. Only recently have I been spending lots of time in the garden.

Thank you for your help.
rhizo_1 (North AL) zone 7
10 years ago
I feel quite sure that your hollies have a scale infestation. These little insects excrete the sugary honeydew upon which the black sooty mold grows.

You can wash and wash that stuff off forever, but it will keep coming back until you get rid of the 'real ' problem....the insects. Again, I strongly suspect scale insects.