A Woodland Patch

[David Nicholson]

I have only one tree in my garden and it's really a beauty-Cornus controversa "Variegata" or "Wedding Cake Tree" and underneath it are a couple of patches of Cyclamen Coum, a few self seeded Primroses and some English Bluebells. The tree is about 20 feet high and so could feasibly grow by another 20 feet.

My problem is that that the soil under the tree is now concrete hard as a result of the mass of fibrous roots from the tree to the extent that the only way I could hope to plant anything further would be to use a pick or mattock to excavate a planting hole.

I would really like to improve the soil structure around the tree by adding about a 2 inches of compost/composted bark but although I would be happy to start again with Bluebells and Primroses I am loath to dig up the Cyclamen. The question is, if I wait until the Cyclamen have flowered, is 2 inches or so of extra compost going to drown them? If I could get away with it I would achieve a new planting area of about 8 feet by 8 feet. Sorry, but I tend to have some difficulty in converting to metric measurements- (it's an age thing ).

[David Shaw]

We took out an area of grass beneath a large, old ash tree and raised the soil level to create more of a woodland garden. It is working but what we have found is that the ash is putting fibrous roots upwards to try and claim the new soil. So far this is manageable and we remove root when possible during weeding but it was a surprise.

I don't know if the Cornus will show this same behavoure or not but I would try and break up the hard soil in some way before covering it with fresh compost. Unless someone says different I think I would try and lift the Cyclamen and replant asap when you have created your new bed. Don't worry about the bluebells - if you add a foot of compost they will keep on coming.

[Martin Baxendale]

Most cyclamen won't mind a good top-dressing like you suggest (many grow little 'branches' up towards the surface if buried deep, from the top of which flower and leaf stems grow but my worry would be that the tree would fill the top dressing with a thick mat of roots, which the cyclamen might struggle to get through - also, the deeper the mass of tree roots over their tubers, the less water the cyclamen would get. I too would suggest getting them out (with a pick or mattock if neccessary).

[Lesley Cox]

I don't know for sure but it wouldn't surprise me if all trees, given a good top dressing of a compost-like material, send roots UP into it, especially quick growing trees such as birches. Birches definitely do it and so do eucalypts to a frightening degree. I put a load (about 6 cubic metres) of potting mix under and between two gum trees having first put down a sheet of black plastic. Within 6 months the mix was a mass of roots from the gums, and the plastic was welded to the ground with thousands of roots growing through it. The gum roots come through the ground surface in my tunnel too, making great mats under trays or anything on the ground. I assume they come up for the water that is sometimes on the surface. The result is, in the potting mix, that there are tree roots at least 60cms above ground level!

[Paddy Tobin]

David,

I think a two inch top dressing of compost will do no harm whatever to any of the plant you have growing. The tree roots, of course, will take advantage as well but if you plant in whatever you want after putting down the compost then they will get settled in before the roots invade.

I have a line of ash trees along the boundary ditch of my garden and running along the back of my compost area. Two years ago I stacked the turves I had lifted when making a new bed in the garden in a heap, 6 feet X 6 X 5 high. When I was taking this out last month to build up another bed in the garden I found that the ash roots ran completely through it, right to the top. They were reasonably soft and easily cut with the spade as I dug.

Paddy

[SueG]

Hi David
I don't think 2" of compost will make any difference to the plants already there - in a sense it is just like an extra thick layer of leave mould which would occur naturally and woodland plants are presumably used to putting up with that competition. I used to have a weeping birch and along with the spring stuff underneath it, I found it a useful place for growing one or two things which would otherwise have been too vigorous in the open garden, but the tree roots slowed them down enough including a nice Vinca. I don't think I ever used a pickaxe to make a hole but I did use a mattock (one of the best gardening tools, to my mind) once. yes the roots got everywhere but the bulbs and the like just seemed to grow around and through them. The worms soon drew any top dressing like your suggesting into the soil so nothing was smothered.
Good luck and a whole 64 square feet of new space to plant in - can't see a flaw in your plan at all
Sue

[David Nicholson]

Thanks to all for your contributions. I think I shall wade in and add my compost mix and see what happens.

[David Shaw]

David, I agree. Get on with it.

[Martin Baxendale]

Aaaargh! Just noticed I wrote I'd be worried the tree might fill David's top-dressing with a thick mat of leaves! That makes me sound thick! Of course I meant a thick mat of roots. If you leave the Cyclamen coum in place, David, I'd keep an eye on them and if the tree roots do grow up into the new compost then maybe give the cyclamen a good soak each autumn to make sure they're getting enough water beneath the root-mat, for continued good flowering.

[David Nicholson]

Thanks Martin, I thought you meant roots.

[Cgull49]

David,

I just read in a book on hardy bulbs, written in Canada, that you can easily grown cyclamen coum, c. hederfolium,... here in the colder parts of Canada by planting them 30cm to 60cm below ground.  The colder the climate the deeper you plant them.  The author Larry Hodgson who lives in the province of Quebec (z4-5) has had great success following this approach.

So I would think you should be able to add plenty of humus to your soil and the only thing you need worry about is putting too much over the roots of the tree and not the cyclamen.

The details of the book are as follows: Les bulbes / Larry Hodgson; Saint-Constant, Quebec; Broquet, 2004; ISBN 2890005844 (v.1).
Alternate title: Les bulbes rustiques

Rob

[David Nicholson]

Rob, thanks for that.