what shall I do about this border?

[iheartdusty]

I have a narrow border next to the house wall which has become a problem. About eight months ago we had damp work done which resulted in a French drain, ie a trench was dug and filled with gravel and a drainage pipe, and there's now only about 20cm depth of soil over it.

The real problem seems to be what the builders did next. I guess they picked up some sacks of compost from the garden centre and tipped them in to replace the topsoil, but I am very puzzled as to what they've used. It's extremely black, it's bouncy and springy, and it won't absorb water! the water just sits on the surface for up to half an hour before it will soak in. What the heck did they put in there? This is eight months on, and it hasn't really changed. There are absolutely no worms in it, and very few weeds (unlike the rest of the garden next to it)

I chose some plants that I thought would manage with shallow soil, some rosemaries, a euonymous, and a sage. But the rosemaries are very unhappy. One or two of them still have pot-shaped compost. They are curling and fading.

Further along, I put in some ipomoea, which have just withered away. They have been watered - I was nursing them along, especially as it's next to a wall, but they have just given up.

So I figured:

• maybe the compost is too nutrient rich; but with such a shallow depth, it should wash out fairly quickly.
  
• it seems that the compost won't take water, and the rosemaries are dehydrating. I have watered them, we had weeks of rain before, but they are just dry.
  
• do I have to dig out the compost and replace it? What would be the best thing to use?
  
• any other plant suggestions for the shallow depth? I'm looking for evergreen plants with small-ish leaves as a backdrop to the rest of the garden.

[ninjasquirrel]

Instead of trying to get plants to grow in the border, what about digging maybe 3 holes just in front of it and putting climbers in or plants that will spread to make ground cover?

[funnyperson]

The black stuff may not be compost it may be tar or similar - perhaps ask the builders as they may have the receipt for the 'compost' if thats what it was. Otherwise it sounds as though ou may have to get rid of the stuff- no weeds sounds ominous!

[purplewithred]

Could it be chipped bark? Whatever it is it sounds all wrong. But a French Drain up close to the house needs to drain - I'm not convinced it should have anything on top that could wash down among the gravel and ultimately clog up the drain if it's designed to keep damp away from your walls.

Definitely ask the builders.

[iheartdusty]

thanks - all helpful.

unfortunately I can't dig holes anywhere else, my only other option would be to give up and cover it with slate or gravel.

i have googled french drains, and it does seem that it's ok to overplant them; the builders themselves said that it would have a soil topping; provided the gravel/shingle mostly stays in the trench where it was put, it will function, and the drain pipe is a sealed one which takes water from a wall drainpipe.

I think if I am going to be able to grow anything there I will have to dig out the 'compost' and replace it with topsoil. I don't think it is tar, it is like earth/compost but with this weird springiness and non-absorbence.

you're right, I will ask the builders.

[cantspel]

Can you dig in some sand and grit to improve drainage?

I cant see why they would use compost as topsoil is cheaper.
Maybe take half out and mix in topsoil sand and grit together?

[iheartdusty]

I thought of that cantspel, but given that the plants will be sitting inches above a gravel/shingle filled pit, I was concerned that the drainage would become too sharp.

I am half wondering if it is some kind of peat? Pure peat?! surely not. ( I live in East Sussex, it's hardly a local resource).

or manure? if you just tipped out a bag of manure, or mushroom compost, and trod it down, would it end up like a springy water-resistant mass?

anyway I picked up some topsoil today, and I will email the builders to see whether they can shed any light.

[LadyMud]

I've just asked a Structural Engineer (DH) who reckons that it's rubber granules. Best to leave it, he says, and maybe put some tubs on top.

[iheartdusty]

yikes!!

could that be it?

poor plants!

I am now downcast, this whole French drain thing has spoiled the appearance of the garden and I will have to re-render and paint the wall which previously was hidden by a nice row of lovely plants.

[LadyMud]

Re-rendering and painting sounds a bit extreme! Why not just get some tubs and plant a couple of climbers. I'm not a big fan of ivy (and the Structural Engineer hates it), but a golden variegated ivy might look good - and hide the wall.

Or some painted wooden trellis would distract your eye from the condition of the wall.

Don't despair, iheartdusty, it'll soon look lovely . . . and without the original damp problem!

[funnyperson]

Yes to trellis and and climbing plants in planters, but no to ivy what about Clematis Montana Broughton Star

[funnyperson]

Interspersed with a Clematis Countess of Wessex
and a climbing rose and/or wisteria

[iheartdusty]

I do love clematis, and I don't have any at present.

If the tubs were pretty big, how much watering would be needed? Would they survive a 2 week holiday in really hot dry weather?



It's actually the front house wall, so it's a low-ish area of wall under the windows, and not suitable for wisteria, but some scrambling clematis and a rose might be ok if they agreed to grow sideways rather than upwards. I have a euonymous, and I could try other shrubs, maybe a quince.

[funnyperson]

They would survive as long as they weren't unglazed terracotta which looses water really quickly.

[iheartdusty]

thank you funnyperson.

I do love reading your posts, you write so beautifully about your garden.

[funnyperson]

Thank you