What is wrong with my Spirea - Ask Extension
These three spirea are planted in the front of my house which faces North. There are in ground sprinklers which hit all three, however, the sprinkler ...
Knowledgebase
What is wrong with my Spirea #799943
Asked July 07, 2022, 5:59 PM EDT
These three spirea are planted in the front of my house which faces North. There are in ground sprinklers which hit all three, however, the sprinkler system is controlled by the homeowners association and I have no control when they run. These plants were planted September 2020. I did trim them late spring. It looks like to me that the plants are in good shape with the exception of the outer leaves.
Scott County Minnesota
Expert Response
Thank you for writing.
This is a pretty interesting set of pictures but it is not close up enough to give the answer.
https://portal.ct.gov/CAES/Plant-Pest-Handbook/pphS/Spirea-Spirea#:~:text=Diseases%20caused%20by%20Fungi%3A,indicates%20infection%20by%20this%20fungus.
Do this, take a picture of the underside of about 6 affected leaves and their stems and send that to me.
This is a pretty interesting set of pictures but it is not close up enough to give the answer.
https://portal.ct.gov/CAES/Plant-Pest-Handbook/pphS/Spirea-Spirea#:~:text=Diseases%20caused%20by%20Fungi%3A,indicates%20infection%20by%20this%20fungus.
Do this, take a picture of the underside of about 6 affected leaves and their stems and send that to me.
I took a cutting and found white webbing within the rolled up leaves and also a small worm.
Thank you for writing back.
I think you have two issues here. A primary fireblight and secondary invasion of the weakened plant by aphids and mites that are making the webs. The primary disease is causing the blackened (fired) twigs.
Agreessively prune out crowded and diseased branches, taking care to sterilize your equipment as you move from plant to plant.
https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/bacterial-spots/fireblight.aspx Bag and destroy pruned plant matter.
Clean up under the plant
When you are finished, mist the plant with Neem Oil (not Neem Oil and PYRETRHIN).
Sit back for two weeks and write back.
I think you have two issues here. A primary fireblight and secondary invasion of the weakened plant by aphids and mites that are making the webs. The primary disease is causing the blackened (fired) twigs.
Agreessively prune out crowded and diseased branches, taking care to sterilize your equipment as you move from plant to plant.
https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/bacterial-spots/fireblight.aspx Bag and destroy pruned plant matter.
Clean up under the plant
When you are finished, mist the plant with Neem Oil (not Neem Oil and PYRETRHIN).
Sit back for two weeks and write back.
Hi
Sent from my iPhone
I pruned as you said but the three in the front are dead in the interior. I also have three plants in the back of the house facing north that are just starting to become infected. The interior leaves are yellow. What do you think? Is this a lost cause? These were planted by Mulligans as part of our HOA. Should I contact them to remove the plants? It is our responsibility to maintain the landscaping.
Thanks for your help.
Nancy
Sent from my iPhone
On Jul 12, 2022, at 3:29 PM, Nancy Hoffman <<personal data hidden>> wrote:
We’ll I pruned as you said but the interior of the plants are dead (see picture). These are the three plants in the front. I also have three plants in the back of the house facing North that are just starting to be infected. The interior of those have yellow leaves. Is there any hope at this point? All these plants were planted by our HOA (Mulligans) but we are to maintain them. What do you think?Thanks for all your help!NancySent from my iPhoneOn Jul 11, 2022, at 5:14 PM, Ask Extension <<personal data hidden>> wrote:
Hi
Sent from my iPhone
I pruned as you said but the three in the front are dead in the interior. I also have three plants in the back of the house facing north that are just starting to become infected. The interior leaves are yellow. What do you think? Is this a lost cause? These were planted by Mulligans as part of our HOA. Should I contact them to remove the plants? It is our responsibility to maintain the landscaping.
Thanks for your help.
Nancy
Sent from my iPhone
On Jul 11, 2022, at 5:14 PM, Ask Extension <<personal data hidden>> wrote:
Hi
Sent from my iPhone
I pruned as you said but the three in the front are dead in the interior. I also have three plants in the back of the house facing north that are just starting to become infected. The interior leaves are yellow. What do you think? Is this a lost cause? These were planted by Mulligans as part of our HOA. Should I contact them to remove the plants? It is our responsibility to maintain the landscaping.
Thanks for your help.
Nancy
Sent from my iPhone
On Jul 11, 2022, at 5:14 PM, Ask Extension <<personal data hidden>> wrote:
Hi
I pruned as you said but the three in the front are dead in the interior. I also have three plants in the back of the house facing north that are just starting to become infected. The interior leaves are yellow. What do you think? Is this a lost cause? These were planted by Mulligans as part of our HOA. Should I contact them to remove the plants? It is our responsibility to maintain the landscaping.
Thanks for your help.
Nancy
We’ll I pruned as you said but the interior of the plants are dead (see picture). These are the three plants in the front. I also have three plants in the back of the house facing North that are just starting to be infected. The interior of those have yellow leaves. Is there any hope at this point? All these plants were planted by our HOA (Mulligans) but we are to maintain them. What do you think?
Thanks for all your help!
Nancy
Sent from my iPhone
Sent from my iPhone
On Jul 11, 2022, at 5:14 PM, Ask Extension <<personal data hidden>> wrote:
Thank you for writing.
I am not convinced the plant is dead. The inner leaves could simply be sun starved. I need a shot of the plants as a whole after pruning.
I am not convinced the plant is dead. The inner leaves could simply be sun starved. I need a shot of the plants as a whole after pruning.
Here’s pictures of the plants after pruning. As you can see the ones in the front are worse than the plants in the back of the house. I haven’t sprayed with neem oil yet but if you think it would bring them back I’ll do it today.
Thanks,
Nancy
Thank you for writing back.
This Spiraea is a RoseMeadowsweet, aka Spirea splendens https://www.wildflower.org/plants/result.php?id_plant=SPSP2 https://www.gardenia.net/plant/spiraea-splendens
The full height of this is 2-3 feet high. It propagates by seed.
The second site I gave you has pruning instructions.
You have multiple plants. They seem to show signs of overwatering (sprinkler?).
They have not been pruned per care instructions in second link. Spent blooms have not been removed.
I do not see evidence of heavy pruning in the fall to ensure blooms. The plant is dense that will encourage bugs like aphids.
I will guess that the yellow leaves were shaded before you pruned the plant.
For now, I would prune spent blooms. If you are near a major garden store, you can buy a pack of ladybugs, bring them home and keep in refrigerator until dusk. Lightly mist the plants with water. Then shake that bag of ladybugs all around your plants. In two days you should see healthier plants and the sated ladybugs will move on.
If you can not find ladybugs, use a light and properly diluted spray with NEEM OIL (NOT with pyrethrin!! read the label).
Prune in the fall as directed. https://www.gardeningknowhow.com/ornamental/shrubs/spirea/cutting-back-spirea-shrubs.htm#:~:text=Fall%20is%20the%20time%20for,plant%20won't%20bounce%20back.
Next year will be better.
This Spiraea is a RoseMeadowsweet, aka Spirea splendens https://www.wildflower.org/plants/result.php?id_plant=SPSP2 https://www.gardenia.net/plant/spiraea-splendens
The full height of this is 2-3 feet high. It propagates by seed.
The second site I gave you has pruning instructions.
You have multiple plants. They seem to show signs of overwatering (sprinkler?).
They have not been pruned per care instructions in second link. Spent blooms have not been removed.
I do not see evidence of heavy pruning in the fall to ensure blooms. The plant is dense that will encourage bugs like aphids.
I will guess that the yellow leaves were shaded before you pruned the plant.
For now, I would prune spent blooms. If you are near a major garden store, you can buy a pack of ladybugs, bring them home and keep in refrigerator until dusk. Lightly mist the plants with water. Then shake that bag of ladybugs all around your plants. In two days you should see healthier plants and the sated ladybugs will move on.
If you can not find ladybugs, use a light and properly diluted spray with NEEM OIL (NOT with pyrethrin!! read the label).
Prune in the fall as directed. https://www.gardeningknowhow.com/ornamental/shrubs/spirea/cutting-back-spirea-shrubs.htm#:~:text=Fall%20is%20the%20time%20for,plant%20won't%20bounce%20back.
Next year will be better.
My sheet from the home owners association says these are Tor spirea. Does that make a difference? We’ve noticed this a problem throughout the neighborhood. If one treats the problem but next door doesn’t will that just reinfect ours?
Sent from my iPhone
Sent from my iPhone
On Jul 13, 2022, at 11:11 AM, Ask Extension <<personal data hidden>> wrote:
Thank you for writing back.
There are 80 species of spirea and many more variants.
All get treated essentially the same.
The susceptibility to pests is largely a matter of how well the plant is cared for. Overgrown, crowded spirea with dead flowers will show interior shading and dead sticks as well as be more likely to get bugs.
A picture of this plant in bloom might help finalize the species.
There are 80 species of spirea and many more variants.
All get treated essentially the same.
The susceptibility to pests is largely a matter of how well the plant is cared for. Overgrown, crowded spirea with dead flowers will show interior shading and dead sticks as well as be more likely to get bugs.
A picture of this plant in bloom might help finalize the species.
