A laurel hedge that's mostly thriving has a few plants aren't. All have a few problems.
I have laurel hedge that was planted in stages over a few summers. It appears that I might have two issues with different parts of the hedge. The first stage planting of the hedge is hardly growing at all after about three years and it looks quite diseased and I'll. The leaves are yellowing again this season and it isn't the normal purge of internal leaves. It had new spring growth which got my hopes up that maybe the problem had resolved. With these new symptoms it now it looks like another stressed summer. I've enclosed two pictures of these plants. The rest of the hedge has had phenomenal growth and they are only about two years old. From day one, a significant portion of these otherwise healthy parts of the hedge is being attacked by something Leaving the leaves riddled with holes. I don't see any bugs on the leaves. I believe I'm dealing with two different problems on the same hedge. The -yellowing and poor growth problem- and -a critter or disease attacking the leaves in otherwise healthy section of the plants.-
Do you have any suggestions with what this could be any suggested solutions? Photo one and two are the yellow leaves and poor growth plants. Photo three is the otherwise healthy substantial growth plants but something is attacking the leaves. Thank you, Rick
Washington County Oregon
Hello. Thanks for your questions and for the photos. While the diagnosis is quite clear, determining the cause, and recommending an appropriate treatment are less so.
The diagnosis is "shot hole" fungi.
When a spore lands on a leaf and starts the infection process, the plant walls it off and creates a circular dead zone around it. The walled off tissues drop out and to the ground creating that “shothole” appearance.
This disease is common in spring but not when we get to the drier weather of summer. Air circulation around the (hedge) plays a big role in how much disease is seen. Airflow near the top ... is usually good enough that the disease isn’t significant there. But look into the middle and lower part of the (plant) and you will see that the disease is much more evident. Severe infections will drop many of the leaves.
Blame the weather. Our long cool rainy season is the likely culprit.
What can you do about it? Here are suggestions from Pacific Northwest Pest Management Handbook.
For disease-induced shothole, try the following.
- Avoid overhead irrigation or apply such that plants are not wet for extended periods of time.
- Remove and destroy fallen leaves.
- Do not plant near other flowering or fruiting Prunus spp.
- One nursery reported good success with first growing in the field and then potting plants the year before sale rather than starting with containers.
- The cultivar Chestnut Hill is reported to have superior resistance to shothole when compared with Otto Luyken.
Chemical sprays are available but it is not the appropriate time of the year to use them and none are available for household use.
The yellow leaves do not appear to be a systemic problem as the newer foliage appears to be green. Just remove the yellow leaves.
I hope this is helpful. Best of luck.