Lavender SOS

[AiryFairy1]

Help! We’re losing a second batch of lavender plants.
The first batch (14 x approx 20cm high plants) wasn’t planted out properly and underwatered in the very hot days following planting, so that’s on us.
The second batch was planted out much more carefully, has a layer of fine bark mulch, as advised by the supplier, and has had meticulous watering - I wouldn’t say too much, but we came home last week from a short break to find 3 out of the 14 starting to look very sad, and now the others are starting to look that way as well, despite daily watering in this hot weather.

I’m not sure this is relevant, but the worst 3 are in very similar planting positions to the first ones to go of the first batch, if that makes sense? So we wondering if it’s the soil?
Any advice is very welcome!

I think that’s bizarre advice re the bark.
Lavenders need a sandy ‘poor’ free draining soil.
I wouldn’t use form of mulch apart from gravel or sand.

That lavender looks like the ones I recently bought, they looked lush and healthy in the pot but the soil was soaked, they had been overwatered and the roots (and plants) were dying.

I washed off all the soil from their roots and put them in a sandy soil in full sunshine.

A few were too far gone and completely died, most of them went grey brown and dry then regrew new fresh healthy growth from the bottom.

If you stick your finger into the soil under the plant what does it feel like?
If it’s moist at all I’d suspect overwatering which causes the roots to rot abd the plant to die.

Oh also, if you gently pull one of those browning stems, does it fall away from the plant with virtually no resistance?
If so, that would suggest root rot (overwatering)

@Borderstotheleftofme thanks for your reply. I think overwatering could be the culprit.

I just checked and the soil is damp but not sodden. Close to the base of the stems of the plant in the picture, there appears to be a white residue which could be mildew/mould.

We’ll hold off watering for a while and see if that helps the others.

Is there a flat green plant growing with it too on the soil surface with thick, fleshy leaves?

I would pull the lavenders out and check the roots, remove any blackened, soft roots.

Add sharp sand to the soil before replanting it, you want a sandy, free draining soil for lavenders.
Make sure it’s in a sunny location.

And get rid of the bark mulch.
If you are gong to mulch it Lavender wants a light coloured, gritty mulch that doesn’t hold moisture.

They may be too far gone but hopefully you’ll notice fresh new growth at the bottom of the plants soon