Portuguese Laurel - Root Rot?

Morning lovely people

Root rot in Portuguese Laurels. Is it the terminal disease that my googling seems to suggest or is it something that a tree can manage by itself?

I planted 7 trees 2 years ago in my new build garden, a garden that I went on to find had significant drainage issues that winter where periods of heavy rain would result in standing water. After having the garden landscaped and levelled, and lots of hours working to improve the drainage (removing countless Hippo skips worth of rubble) the issue seems to be much improved.

I have lost one tree to the rot, 2 more haven't died but their growth is heavily stunted, and as the trees get further from the flooded area they get better. I'm starting to wonder if that winter of flooding has caused root rot to set in and some of the trees are still battling with it.



I decided to investigate the roots more to see what I'm dealing with, and to my surprise it looks like even the largest, healthiest of the trees have rotted roots a little under the surface.




Has anyone experience root rot for plants in the ground? For all the googling, and youtubing, it seems that the focus on potted plants and the advice to re-pot and clean is much more practical. But digging up 6 trees seems excessive, especially when some are growing and seem healthy?

Am I paranoid about the disease after losing 1 tree and 2 clearly have it? Or should I be concerned about all of them?

 

Its likely they all still get stagnant water. What happens is the roots are submerged and the water becomes hypoxic due to bacteria eating the little o2 water can hold: the roots then suffocate as they need oxygen like us to survive. It isnt necessarily a pathogen causing this. Different plants tolerate different hypoxic levels.

Bays are pretty tough, it may be possible to grab them out of the ground and put them onto raised mounds so the root ball is above the base layer of the soil. This is done for fruit trees in wet areas. They would be able to form a layer of roots that may let them survive flooding.
They may survive anyway if you dont but bad flooding will just repeatedly kill the roots and make pathogens more and more likely.

Something to consider is selling them while theyre alive and young and getting more tolerant plants. Ultimately bays are from quite dry conditions. Elder, Willows, Sea Buckthorn and a few others tolerate wet roots much better than any laurel will. For evergreens there arent many that like wet soil. Holly will tolerate it better than laurel but...

Very dense plantings of willow or elder will still give winter privacy. Its more about the energy/vibe then actually not being able to see through it IMO.

 

Suggest you feed them (Vitax q4) and mulch them with organic material. They will root in to the enriched layer, they are happy to be relatively shallow. As the size variation in your picture above suggests, they may be responding to the amount of light (total solar) they receive; its difficult to move the shadowing buildings etc so you may have to prune to equalise the appearance.

 

Thanks both, really useful information.

I really like the Laurels so want to give them the best go possible. Raising on mounds is a useful tip, is there a good (or bad) time to do this?

Thanks for this information. I will take a look at some Q4. The light levels are quite even for the trees, from about 10am right through to the evening they are in the sun. The previous flooding was always localised the further left you go in the image and beyond.

 

I think if you can water them a bit after do it while they have time to recover before winter. But it may be better to do it after they go semi dormant. I really dont know, sorry.

 

With further consideration of the situation, do you think you have resolved the inherent drainage issues ?; winter 2023-24 was wet by anybodies experience.
There is a recurring theme to questions from new gardeners in new build properties upon this forum.
Unfortunately, it seems, too often building is permitted on floodplain and/or construction destroys any established drainage patterns. When combined with neglect of drainage maintenance or streams and rivers by EA for 'budgetry' reasons and continued hardscaping of developments without adequate provision of drainage; the reliance of infiltration where it fails to work and a total disregard by builders that one might conceivably wish to utilise the outside space for growing, so much frustration is caused.
It will likely be an ongoing issue, one can only encourage you to persist and hopefully achieve a satisfactory equilibrium. Good luck.

 

Are the sickly ones still alive @Ian G ? No point trying to encourage them if they're on their way out.I can't tell from the photos, but that's probably just me!
The problem with many plants/shrubs grown as standards is that they don't always transplant and grow as readily as they would if they've been left to grow naturally. If you plant something mature [ those look like they're mature specimens] it's also harder to keep them happy initially.
Unfortunately, as @infradig has said, there are no short cuts with the ground on new builds, and it pays to really improve the ground enormously before planting. It also means waiting, so the other alternative is large, raised beds to allow planting to happen more quickly.

 

The proof will be in the pudding this winter but I'm as confident as anyone could be at this stage. The garden suffered from the all the common issues that come with new builds; clay, heavily compacted soil, rubble. Tie that in with a garden that was on a gradual slope and uneven in places, it led to areas of water pooling (particularly in winter 23/24). I have had good quality landscapers in, their main purpose was re-turf the lawn and level the garden, but we took the opportunity to assess the soil quality and try to improve drainage. Areas of rubble and poor quality soil were replaced to give a healthy depth of top soil that should hopefully resolve any issues. The flower beds have been dug up by myself and mulched heavily twice a year, I can see that the soil in the beds is much healthier.
So I'm really hoping the job is done, or going in the right direction.

 

The sickly ones are alive but their growth is incredibly stunted. To top off a tough life for them, last year they were hit hard by an infestation of caterpillars that cocooned in their leaves and ate them (my first experience with this, and something I'm much more on top of observing this year). I just planted a new laurel in the place of the old one today, raised it slightly and hoping that this one does better. You can really see the impact on the 2 trees to it's right, which have had 2 full summers in the ground.