Beds around trees - have I made a mistake?

Hello,

I have some large trees in my garden and thought that it would look good if I planted daffodils around them in circular beds. I've laid new topsoil around the base of the trees. The soil is probably about 3 inches deep and is slightly banked. I've since been told that this is going to damage the trees. Can anyone please advise if this is the case and, if so, what should I do now? The soil has been down for only a couple of weeks so far.

I'd appreciate any advice as the last thing I want to do is ruin the old trees.

Many thanks,

Madamemorty.

 

Can't see how. Tree roots for most trees are usually quite deep and spread out to mirror the size of its canopy. A few bulbs won't harm them.

We've got a young almond tree in the middle of the lawn. I built a brick circle round it to make mowing up to it easier and I've planted three white dwarf rhodos. I'm hoping eventually they'll completely fill this bed, I'll possibly layer them to help speed them along.

 

I can't see 3 inches of soil doing much harm to mature trees.

 

Thanks Doghouse Riley for your quick repsonse. I'm really worried. I'm new to gardening and was enjoying it up until now.

Your tree arrangement is lovely but our situation is slightly different. Our four trees are very big and must be 40 to 50ft tall. I think the potential problem is that the soil is banked up against the trunks. Now, it was banked like this when we moved in (2007) but I suspect it was like this for a long time as it was covered in brambles, grass and weeds. We cleared the weeds, laid about 3 inches of new topsoil on top of the banked earth and then planted about £300 of bulbs.

I don't care about the bulbs so much as the potential harm done to the trees. I'm one of those people who considers it a sin to cut down (or damage) a tree that has grown for such a long time.

Any other thoughts?

 

Madamemorty

Has anyone explained how your bulbs are supposed to "do harm" to your trees?

The bulbs themselves will not harm your big trees in any way whatsoever that I can think of. Tree roots go far deeper and wider than most people realise.

The only question is whether the banked up soil by itself will in some way cause harm but if it's been like that for years, it's highly unlikely. What type are your trees?

 

We have planted around three large ash and one lovely sycamore.

It was a tree surgeon who passed on the advice that it is wrong to bank soil against tree trunks. Perhaps, though, he didn't realise that the earth was already banked and that we just added a few extra inches of depth

 

All plants will compete for nutrients, but there should be enough to go round, especially if you remember to give it bit of miracle grow (or similar) from time to time.

A quick stroll in any deciduous woodland will show how much plants damage trees. It seems to be they just don't. Nature has evolved lots of different tricks in this respect, and you'll find that a woodland left to its own devices is not just a single storey of trees, look at it again and you'll see it is lots of different layers of smaller things growing beneath bigger things.

It'll be alright I reckon.

 

Thanks clueless1. You don't think that the soil could cause the trunk to rot then?

 

Soil banked against tree trunks can harm the tree. Now, I don't know at what level the soil has to be to do this. What happens it that bugs in the soil can now start eating at that portion of the trunk and cause harm to the trunk of the tree. Three inches is an ample hight, for me I would not have done it. Also unless your soil is so bad, bulbs really are not that fussy with soil.

 

Soil against bark can rot the base of the tree. In your case however it will probably be fine. If you have just replaced soil up to the level of the soil you removed, then surely the tree was coping just fine, and will continue to do so.
If you are that worried, just scrape a bit of soil away from the bark, it won't be that noticable.

I have been told to avoid soil against bark, but this is usually when planting young trees. I had a couple of young trees that I built up soil around, probably to a depth of 5 or 6 inches. I put a small planting pot with the bottom cut off round the base of each tree to keep the bark away from the new soil.

 

I've found the biggest problem with trees rotting at the base is down to drainage and compaction of the soil more than anything else. I have a couple of trees on my land that are now leaning at 45 degrees due to subsidence of the soil at the top of the bank building up against the trees (not in a dangerous position), those trees are doing fine.

On the other hand last winter we literally lifted out about a third of the trees in my main hedgrow because they were so rotten. In those cases what had happened was a field drain had become blocked, probably several years ago, so the trees were literally sat in soggy soil all the time.

I've also seen problem trees on my land where the soil is so compact that they struggle to get good roots down, so the wind just keeps damaging their roots.

I guess it depends on lots of different factors. Drainage, light and warmth, possibly even the tree species all play a part in deciding whether a tree will rot at the base or not.

I'm not a tree expert, so I can't give sound scientific advice, I can only go by what I've seen.

 

Trees... they can be fickle things.

Good arboricultural practice does advise against changing the soil depth around a tree. This is for various reasons including but not limited to:

• It can alter the soil's pH level
• It can alter the rate of water absorption
• It can introduce new pathogens into the root collar
• It can add to compaction problems
• It can alter the delicate symbiotic relationship between the tree roots and the benficial mycorrhizae fungi that live in and around the root hairs.

A 3" change may not seem all that much, but it some circumstances it has the potential to make all the difference. Now ash and sycamore are pretty hardy, robust trees that are hard to kill off. If we were talking about a precious specimen tree then I'd be erring on the side of caution and telling you to remove it. However, it is up to you whether you wish to take the risk or not.