Plants beside external walls

[Liz Kershaw]

Happy New Renovating Year, everyone.

I've been busy outside tackling the overgrown gardens around our new cottage.

We have a narrow flower border around the walls (cottage is 16C and timber-framed). The previous occupant had some vile water retaining Triffid type plant there which I've removed and I intend to plant some hollyhocks to aid moisture removal from the bottom of the walls. My question is: does anyone have any suggestions for a lower border plant which will continue the work of keeping the walls free and drained? Preferably one in keeping with a cottage garden. My preliminary thought is lavender ... but am I being unoriginal?

Thanks!

Liz

 

[tobydog]

Hi Liz - When you say you have a narrow border around the walls, are you talking about all four walls? If so, then the north and east will normally support different plants to those in the south and west.

What is next to the borders - gravel paths and lawns, or paving slabs?

You are asking about plants that will aid moisture removal from the base of the wall but I assume you want something that achieves this but without having invasive roots. You mention lavender but this is a plant that thrives in conditions that are already dry and with poor soil. They are very low users of water and therefore will not achieve what you're after. We have lavender on our south wall and it thrives in the baking sun and under the 3ft thatch overhang so is very dry. We also have hollyhocks along the same wall and they thrive in the same conditions.

Do you actually have a wall moisture issue you need to fix or are you thinking that plants will just help to keep it drier than it already is? Choosing plants to achieve this could be quite complex.

 

[Penners]

As Tobydog has said, lavender is unlikely to achieve what you want. However, I wouldn't be too concerned about this dilemma. I find it very difficult to believe that your choice of plants would make the difference between a damp wall and a dry one. Personally, I would just plant what I liked, steering clear of plants with invasive roots.

As a suggestion, how about some plants that will make a considerable amount of "top" without too much of a root. Maybe a few clematis or some climbing roses? They should be fairly thirsty, but will have the benefit of not shading the soil too much - thus allowing a decent amount of evaporation.

Just be careful to avoid aggressive rambling roses, such as Kiftsgate or Rambling Rector. After a few years you might have trouble finding your house. Stick to climbers, rather than ramblers.

 

[Duchess]

Please beware... Thinking invasive roots are not too much of a problem with timber framed cottage as no foundations to disturb, until we found a neighbours root growing into the house!

 

[Flyfisher]

Beware of hollyhocks, lest they take over . . .

 

[jocelyn plummer]

I rather like Rambling Rector(s)----

 

[Liz Kershaw]

Thanks all, the wall in question is SE facing and the other side of the border is a path. I suppose I'm more concerned that the plants I choose won't make the walls damp rather than dry them out - I hadn't thought about invasive roots so I'll be aware of that one.

Anyone know a good online nursery?

 

[MatthewC]

Personally, I think that almost any plant beside a stone wall will encourage dampness, and the only things you should put there are low plants. A mass of hollyhocks, or anything on trellis like roses or wisteria, will both shade the sunlight and act as a windbreak, each of which will reduce evaporation and hence encourage water retention in the wall. Conversely the only place on my house where there were plants and no dampness was where the ivy was so thick (8-10 inches or so) that it was bone dry underneath and the wall was perfect (see http://houseintheenchantedforest.blogspot.co.uk/2010/10/teetering-on-brink-of-progress.html).

 

[Penners]

I think that almost any plant beside a stone wall will encourage dampness

I would agree with you if the plants are "clinging" climbers, which hug the wall. However, something like a climbing rose will be grown up a trellis, which should stand away from the wall by perhaps 2-3 inches, allowing air circulation between/behind it. Rose branches and foliage are also fairly un-dense in their growing habit.

So I don't think I would be unduly concerned about a damp wall.

 

[MatthewC]

I think that almost any plant beside a stone wall will encourage dampness

I would agree with you if the plants are "clinging" climbers, which hug the wall. However, something like a climbing rose will be grown up a trellis, which should stand away from the wall by perhaps 2-3 inches, allowing air circulation between/behind it. Rose branches and foliage are also fairly un-dense in their growing habit.

So I don't think I would be unduly concerned about a damp wall.

Well, the west-facing side wall of my house was just around the corner from the mass of ivy on the front, and had only a small amount of ivy hanging six inches away from the wall; the wall was damp and pale green with micro-growth, only where there was this ivy. After removal this cleared up of its own accord. I just don't think a few inches of air space actually gives sufficient circulation, especially when we get those frequent rain storms in summer when the plants are in full leaf so the sun never gets on it (if it shines through at all).

 

[Penners]

Ivy us just about the worst plant for climbing up walls. It clings tightly and thickly to the wall, and its tendrils penetrate the surface.

 

[88v8]

Ivy us just about the worst plant for climbing up walls. It clings tightly and thickly to the wall, and its tendrils penetrate the surface.

Au contraire; its overlapping leaves both waterproof and insulate.
Although I wouldn't put it on an unsound wall as it can creep through even the darkest crack.

Ivy also beautifies and lends dignity to even the ugliest modern extension.

Ivor

 

[Penners]

There's a very slight degree of insulation, but I would argue that any "waterproofing" benefit is more than offset by the tendency of the plant to create potential entry points for moisture and to retain that moisture, once it's in the wall. Ivy isn't good for masonry.

As for beautifying and dignifying ugly extensions, there is a huge variety of plants that will do this without the deleterious effects of ivy.

 

[CliffordPope]

the ivy was so thick (8-10 inches or so)

By the time you have ivy 10 inches thick you will have more to worry about than damp!

Ivy is extremely destructive once it gets its tendrils into stone or brickwork. Ive seen a derelict building entirely enmeshed in 4" ivy trunk. The stonework was broken into dozens of chunks, still held roughly in place by a cagework of ivy.

 

[MatthewC]

the ivy was so thick (8-10 inches or so)

By the time you have ivy 10 inches thick you will have more to worry about than damp!

I was most surprised to find that the ivy had done no damage to the squared coursed limestone walls (other then a single root getting through) and had in fact protected it from the damp, which had really messed up the wall elsewhere. However the ivy was playing havoc with the guttering and roof; it was a great relief when I removed the very last bit of ivy from the house - see my blog http://houseintheenchantedforest.blogspot.co.uk/2011/03/ivy-is-enemy-and-fun-with-joists.html

 

[Penners]

The old Hornton stone farmhouse that we renovated in Oxfordshire, some 25 years ago (good grief - is really that long ago?!!), was completely covered with ivy on two of its walls. We removed it all with the most enormous difficulty, but never managed to get rid of all of the dried up tendrils that clung like glue to the surface of the stone. So the house always had a slightly furry look to it!

Pulling ivy off walls is a horrible job. It releases a fine dust that has you sneezing and wheezing like a 50-a-day smoker.

 

[Feltwell]

I've got ongoing battles here with ivy, luckily it's not on the house itself. Doesn't help that I'm allergic to the bloomin' stuff!

Virginia Creeper is not much better - the back of Feltwell towers was smothered in it, totally obscuring some windows, and it had got under the roof tiles. I'm still picking the dried tendrils off the brickwork every time I go up a ladder more than 6 years on, and the little buds at the end of the tendrils that stick to the brickwork won't be parted - I'll just have to wait for those to decompose, if they ever do!

 

[Penners]

The wife in the couple who are our best friends is called Virginia. She's an absolutely wonderful cook, and whenever we eat with them I am always effusive about the meal (I regard it as an investment to ensure future invitations!).

Her husband refers to me as the Virginia Creeper.

 

[MatthewC]

The old Hornton stone farmhouse that we renovated in Oxfordshire, some 25 years ago (good grief - is really that long ago?!!), was completely covered with ivy on two of its walls. We removed it all with the most enormous difficulty, but never managed to get rid of all of the dried up tendrils that clung like glue to the surface of the stone. So the house always had a slightly furry look to it!

Pulling ivy off walls is a horrible job. It releases a fine dust that has you sneezing and wheezing like a 50-a-day smoker.

The trick with the tendrils is to pull them off carefully from the bottom when the ivy is still fresh. They really stick to the wall when you cut the stem and leave them on the wall for too long.

(I was just going to add something about other growth dropping off when it dries out and then realized that it wouild be too much of a temptation for Penners!)

 

[Penners]

Pulling ivy off walls is a horrible job. It releases a fine dust that has you sneezing and wheezing like a 50-a-day smoker.
The trick with the tendrils is to pull them off carefully from the bottom when the ivy is still fresh. They really stick to the wall when you cut the stem and leave them on the wall for too long.

(I was just going to add something about other growth dropping off when it dries out and then realized that it wouild be too much of a temptation for Penners!)

I agree. The ivy that we pulled off the walls of our Oxfordshire house had been there for many decades, and the main stems had been cut through some years before we bought the house. So we had exactly the problem that you highlight. This was an example of growth not dropping off when it dries out. :wink: