It certainly doesn't look good. My initial thought is that the yellowing of the leaves indicates it is either missing one or more nutrients, or the roots are being compromised by a pest or disease that is preventing the plant from functioning properly. Take a look at the roots.

Another possibility is a severe case of spider mites. Any sign of webbing on the leaves and stems? If so, check the underside of the leaves for masses of tiny spider mites.

Finally, has any chemical been applied nearby?

Thanks, coolplantsguy. No chemical has been applied nearby. I haven't noticed any webbing on the leaves and stems, but I'll take a closer look to make sure.

Now that I think about it, this same thing happened to them last year. I chalked it up to the plants having just been planted, but now that's it happened a second year in a row, there must be some other explanation.

I did an internet search last night, and found a couple of other people who had posted about similar issues with their phlox (plants start out healthy, but then begin to die from the bottom up), but none of their questions were ever answered, so it wasn't very useful other than to know it happens to other people.

They are also susceptible to powdery mildew, but that does not appear to be the situation in your case.

I should've also added to cut off at the base the stems that are dying so the plant can put its energy into some healthy growth.

Deanna

Patti, the foliage appears diseased due to the yellow blotching. Try searching for Alfalfa Mosaic Virus or Tobacco Rattle Virus. Either of those can cause the discoloration shown in your Phlox foliage. I gave up trying to grow Phlox here because the Powdery Mildew always made the plants look like crap. :-)

Rosie

Rosie,

My David Phlox looks similar to hers but no brown leaves, and I already whacked it to the ground. If it returns when the new leaves come back--do I dig it up and toss it?

I divided it in early spring, and I gave some to a friend and hers looks the same way. Should she whack hers to the ground? I looked up Alfalfa Mosaic Virus, and I think that is what mine has.

If you're pretty certain that yours has a virus, yes dig it up and destroy asap.

But I don't believe the plant pictured above is a virus.

I think Deanna has your answer with the spidermites and brick. If you can move it to a spot with afternoon shade that will help but right now I would guess the brick is keeping it hot and dry, the side closest to the brick is probably the worst.... plus being next to the house may also put it under the eaves which keeps rain off the leaves -which mites love.

Try watering and give it a dose of fertilizer. When you water, if possible, spray the undersides of the leaves with a pretty good blast... that may wash a bunch of them away. the more water on the underside the better. Three days of that should help, spraying with a little safers soap will help even more. For the long term move the plant.

Thanks, everyone, for sharing all your wonderful knowledge! I am on my way out now to check for spider mites. I'm fairly certain they aren't underwatered, for all the rain we've had here lately, but will make sure the eaves are not keeping the rain from reaching them.

I'll have to buy some peat and sulpher and see if that helps...

If I have to move them, I'll be looking for ideas for tall plants that can survive near the brick!

Patti

Thanks for the advice about the lime leaching into the soil. I think that is one of my problems. Now, here's another- maybe should be a different post, but..... I planted White David Phlox... Now I have pink phlox - no white. What has happened?

The stems are dying from a fungus problem that likely came in with the plants, or is in the soil and garden. It could be Botrytis which is very common, or could be a water mold, which is a fungus-like microorganism called Phytophthora. Both can cause the lower parts of the stems to begin to rot, often spreading from an infected leaf, until a whole portion of the stem is completely dead. The foliage above will first start to wilt and then die. They also both occur when conditions are very wet and poorly draining.

If it is really bad (as in this case) I would consider digging it all up and destroying the entire plant. If it is only a few stems you can cut them down below the dead portions and then treat with a fungicide. I would first treat for Botrytis and see how it does. If the problem still comes back later then you might have a water mold and then you will need a stronger fungicide. Look on the label when buying a fungicide for Botrytis or Phytophthora (the latter is hard to find without going to a commercial spray).

Removing this plant from the landscape may be your best bet if the fungus is in the roots. If it is still only on the stems then cutting it off at the base can stop it. Then make sure the soil surface dries out between deep waterings.

Hope that helps.

Chris

My long lived (18 years) phlox garden suffered a massive, fast dye-out two years ago. I did see webbing on the plants but the destruction was unstoppable in spite of religious pesticide spraying. The plants looked exactly like those pictured. Fearing that fungus was introduced by the insects I also sprayed fungicide to no avail. Last year a few sad little plants came up and received both fungicide and pesticide spraying starting very early in the spring. I did not see any webbing. This year is a repeat of last year. A few Phlox in another location are not affected (yet) but they are in too much shade to bloom. I was hoping to find an answer here.

Apparently there are phlox people and nonphlox people and I'm one of the latter. I pulled up my next-to-last David this morning after years of trying all of the remedies listed above. I think I can get the same general effect with white cosmos, at least it will be cheaper.

I have had Garden Phlox for 20 years. I have the same situation over the last several years. Plants start out good and then they start dying. They even have dead leaves but are still blooming some of them. I have no brick on my building. I believe it to be mites as I did see a spider like web over the top of the blooms on one of my plants. Or could be mites and aphids. I have so many to cut completely down. I have a similar problem with my clematis. It always starts out good, blooms and then the leaves start dying off. I used to spray my garden with Miracle Grow and never had these problems. I definitely need to do something with the soil and start some kind of pest spraying. I don't believe that we can't have our phlox looking good as mine did for a long time.

My Franz Schubert phlox is absolutely gorgeous this year after many years of yellowing and dying leaves at the base. Last fall, I moved it from full sun to a moister part of the garden that goes into shade about 3 pm. Not one yellow leaf on it.

Mayflowers comment is interesting, but it may be your zone is different than op. Adding your zone makes it easier to compare climates between different posters, which helps us figure out the relevance of answers. It's also been suggested adding the name of a nearby city helps hone in geographical variables even more.

Darned if I can remember how to do it. Try going to "my page" and then you can looki carefully at the links provided. Climate zone is def. one of them.

We always have a bit of what looks very much like that happening in the pictures above, each year. And almost always it's in one limited area of the garden; namely, along the back of the narrow beds along the deck.

That's the sunniest area of our south facing garden. I thinned out and replanted the area last year, but the problem (though still limited in extent) is more obvious than last year. And it's only the garden phlox there that seem to be stressed, not other perennials. We water the garden once a week, unless there's lots of rain; every five days if it's really hot.

I suspect the problem is to do with dryness. Against our wooden deck (or the wall above) I'd suspect the soil is particularly prone to drying out. There's also numbers of ants in the location, here, which may also contribute to the soil drying out.

Though not as extensive as in the pictures above, I just cut out any such stem (leaves yellowing and dying from the bottom up). Leave a garden phlox you've purchased in a pot with inadequate watering and these symptoms are just what you get.

I'm not saying, however, that there aren't other stressors also working on our phlox/ those pictured above as well.

Marie Tulin, my zone doesn't matter in this instance. There was a huge improvement in my phlox when I moved it to different conditions. I've been growing this same plant for at least eight years.

eelworms/nematodes. The leaf curling and distorted shapes look like eelworm damage for which, sadly, there is no cure. If the roots are not disfigured with nodule growth, you might try to propagate new phlox using root cuttings (in fresh soil).

I have this trouble when I don't clean up the phlox in the fall by cutting back the stalks and adding fertilizer ( I like aged horse manure) My bed is over 24 years old, and we have bad years and beautiful years. I didn't clean the beds last fall and this year I have little red bugs with a black strip that bite-the rust-and the mold issues (from being too close together) This fall I'll make sure to clean-spray for bugs-fertilize the beds. Next spring will be the proof.

My many-years-old David phloxes have never had any trouble until last year and this year, more this year and last. Dying pattern looks the same, certain stems have their leaves dying from the bottom up. First one stem, then more.

I seriously am suspecting root rot - this spring and last spring were super rainy - rain rain rain. Like I said, never had any trouble with them before. No sign of insects on them.

In the poster's picture (his post is now 8 years old :-), the plants being near the foundation could be getting too much water from a gutter downspout or water cascading off the rooftop.

I also agree that it could also be soil that is too alkaline, because soil around the foundation is generally that way because the building materials leach it.

But since my phlox are nowhere near a wall, I vote root rot.

Missed watering for a few days. 4-5 probably. Should we cut down and hope for growth.

This is what they look like. And it’s only the phlox that’s are dying,wilting