I have a whole row of lavender and recently noticed that one plant is dying with the bottom stems and leaves turning grey and drying up. I have just checked the rest and when inspecting closely at the bottom some of the leaves are turning grey to. Do you know what this might be? Is this perhaps also verticillium?

Many thanks

Gitta

I would guess that the dying stems are being caused by a fungus called verticillium. While it can affect whole plants it more usually is seen in individual branches or stems (a symptom known as inconsistent wilting).

Verticillium is soil borne, and travels from the roots up through the plants vascular system. To protect itself lavender (and other plants attacked by verticillium) block off their water passages in an attempt to stop the fungus spreading. No water = wilting/death of bits of the plant.

Unfortunately, if it is verticillium, then you have a bit of a problem. You can’t cure the plants – they are best removed and burned. AND the disease remains in the soil for a fair while (3-4 years) after the host plants have been destroyed. You can try to be less drastic and just prune out and destroy infected bits. Always disinfect your secateurs in between EACH cut by wiping the blades with a rag soaked in surgical spirit, Jeyes Fluid, Dettol or another strong disinfectant (not bleach). Then feed the plants with a general purpose fertiliser and hope…

Fungal infections are easily spread so carefully clean boots and tools when you have finished…

Good luck

Julian

I know, it can be rough to have to deal with a sick plant – if only we could put them in bed for a week!

Before I jump to any conclusions, what has the rain been like where you are? Has the ground been either very wet or very dry? Have you been watering the plants every day (a common mistake with lavender – if it is dry out, a good drink once a week or so is best)? Do you trim your lavender after it flowers (this encourages good flower production)?

Since you say that you have other lavender plants around it, it does seem unlikely that this one got too wet/dry without the others having similar symptoms. Still, I have to ask.

Alfa Mosaic Virus causes very distinctive, curled up, contorted leaves with spreading yellow patches. On the one hand, this disease is very rare (in the UK at least…). On the other hand, it is fatal and quite contagious, so you really want to get the plant out of there and on the fire if you think that you do indeed have it – if it comes to that, don’t touch the surrounding plants until you have cleaned your hands well.

Get back to me with as much detail as you can.

Firstly, there is no guarantee that you both have the same problem – just about every fungus begins making its way in the world as a mass of white fibres called the Mycelium and most of them fit the description of “melted plastic” (or “strange”, for that matter).

If it is affecting the roots, then there are spores or dormant fungus colonies in the soil and they will continue to re-infect any susceptible plant that you put there. There really is no way of telling what it is – even an expert would probably need to do tests in a lab.

I hate to let you down, but I am afraid that soil fungi are not our area of expertise. When we have had fungi goings ons in our garden in the past, we have resorted to digging out about a metre of soil and replacing it. Then again, we do live in a honey fungus area, so we are quite paranoid about this sort of thing.

The best thing that you can do is to find someone who knows about fungi to come and take a close look – even if you sent us a good photo, I doubt that we would be able to identify the culprit.

Failing that, pull all the plants out, replace a reasonable amount of soil and plant something else – I wish there was an easier option but if there is, we don’t know of it.

Be brave – my grandfather said that if something wouldn’t grow in his garden then it wasn’t going to be invited back.

I live in Rhode Island and my 4 feet in diameter 3 year old lavender is getting that wilty look at the flower and showing only a few buds…leaves have some sort of spot but it is not a dark spot…yellowish grayish. I have about 7 old and new lavenders around it…Ugh…do I have to remove it? and can I spray something on the others? This is a large variety of French lavender. I am sad.