Monday, 5 October 2009

OOTS: Public Space Workshop: Management


At the end of last week we looked at some of the things to bear in mind during the design stage. Of course that's not the whole story: once a scheme is planted up, its aftercare needs to be addressed. Budgetary constraints often means this is minimal and it was interesting to see this was a painful issue for the event's host. After all, if I'd spent a great deal of time making sure my nursery's plants are of the best quality, I'd be upset if I then saw them being poorly looked after or dying on the streets.

For example, on the way back from our nursery visit in the afternoon we passed a long row of multi-stemmed Prunus serrula, no more than 2 years old. They were dying because the design had them perched on the top of low mounds and surrounded by grass. This was taking all the available moisture and so the trees hadn't been able to get their roots down to the now relatively lower water table than if they'd been planted at street level. It was painful to see and I was shocked when I was told the total cost of planting a tree is around £500 when taking design costs etc. into account.

Apparently this isn't an isolated incident. The main killer of our street's trees is drought stress through a combination of one or more of: poor design decisions, incorrect planting or lack of follow-up care. They suggest using the bag watering system shown above, which delivers water through a couple of holes in the bottom of the bag. Whilst it's relatively cheap (£25), I'm to be convinced it has a real place on our streets. I'm sure they'd be relatively easy to vandalise or steal.

Climate Change was mentioned, but was dismissed by Richard Bisgrove as an issue for most current/ proposed schemes as plants are much more resilient than credited. This also assumes the scheme gets refreshed in the 15-20 year timescale mentioned previously. However, extreme weather events are a different matter: an increase in soft, green, absorbant plantings should help to reduce their impact. [Here's Richard's very good article about the impact of
climate change, plus his advice to gardeners from the RHS website] John Tweddle added he needs to keep Westminster's grass green for as long as possible as that helps to reduce London's temperature by 2 degrees centigrade.

Last winter was seen as a 20-year weather event which impacted on commonly used plants such as Geranium 'Rozanne' (died) and Cornus alba (bark eaten by mice). Richard Bisgrove also said sugar maples could become a more viable planting option as our autumnal weather seems to becoming much more like that of the States and Canada.

The rapid spread of horse chestnut leaf miner means they probably won't be used in future planting schemes. Limes (Tilia sp.) and Dutch elm disease resistant Princeton Elm (Ulmus americana) were suggested as possible alternatives. I finally got to speak to our county arborist on Friday about this issue, which I'll tell you about in a future post.

Westminster council has 1 million visitors/commuters passing through their parks every day, so the management of the grassed areas is 'interesting'. Grass mixes suited to dry conditions [thus less irrigation needed] and wear and tear are used, plus mixes for shade where appropriate. In the winter, all grass area are hollow tined and the holes filled with recycled rubber crumb. [this approach might be appropriate for e.g. National Trust's most popular historic gardens - they often cordon off lawned areas to allow them time to recover, though I wasn't sure about the use of the rubber crumb]

Other management strategies adopted by John Tweddle at Westminster council include:

  • There's a tree canopy issue in London as these, particularly the London Plane, are shading out much of the planting below. A programme of crown lifting is being carried out [also needed on the public land next to our house!]
  • Increased use of drought tolerant planting
  • Replacement of annual bedding schemes with herbaceous and shrub plantings to reduce upkeep costs
  • Recycling of green waste as mulch - reduces the need for watering and reduces pests. This also includes the replacement of lawn mowers with ones which return the clippings instead of collecting them
  • Reduced usage of drinking water [i.e. expensive] for watering e.g use of grey water. Also a borehole is being sunk at Lords cricket ground, so hanging baskets will be spot watered via water bowsers filled from there. They've also found no irrigation often leads to better displays when combined with mulching, especially with herbaceous and shrub plantings
  • Use of organic seaweed extracts sprayed on plants leads to hardier plants with increased vigour and disease resistance
A number of these measures [plus a number of other non-plant related ones he mentioned] means reduced upkeep costs. A win-win all round :)
Brita von Schoenaich said that the implementation and maintenance of the design is usually outside of a designer's control and 'creating something beautiful on public land is against all the odds'. I asked her later what the main criteria were in a design brief - budget's the main one, far above anything else. I wonder if this might lead to inappropriate plant choices sometimes i.e. cheaper ones to buy and plant which may need more maintenance. I also got the impression on the day there's not much interaction between the major stakeholders in public planting, which might have a hand in some of the issues mentioned as well as those I've seen Out on the Streets?
I did originally plan another post on planting ideas, but I see I've mentioned most of them in this piece. Lots of inspirational parks and landscape architect's work were shown during the day, which I'll be researching further during the winter months so I can compile a resource guide. It seems more appropriate to do a post on planting ideas once I've completed that work.
I have a post on the afternoon's nursery visit still to do - though you can have a preview via the link and they've got a cash and carry promotion on this week, well worth the effort if you're in the area - but that can be covered outside of Out on the Streets. It was a tremendous day and I came back enthused and inspired. I still don't really understand the end to end process from design brief to maintenance, but perhaps that was too ambitious for the day. If anyone out there has anything that'll help me, do please get in touch!

As well as being my last article on my workshop attendance, it's also my last one for Out on the Streets this quarter. Thanks to those of you who've contributed thus far. If you'd like to contribute, then there's still a few days left for you to do so before I compose my wrap-up post at the end of the week :)

12 comments:

  1. Trees for Cities are one of my favourite charities and they reckon to visit newly planted trees for watering at least every fortnight for the first year. The cost of this is far more, obviously, than the cost of the tree. They also water once a month in the second year too. They lose very few trees compared to the council, though. They also encourage as many young people as possible to come and have a cup of tea on the planting day, even if they don't do any planting at all. Apparently it makes them less likely to swing on the trees at a later date!

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  2. Very good post VP. It points out quite correctly that the initial cost of planting is only a fraction of the long term maintenance. Unfortunately it is this aspect that gets so easily cut back and the trees and landscape suffer.

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  3. Oh I hope to get another post in before your wrap up, but if not hope it is okay if I post it anyway? They have been using those big plastic bags here around newly planted trees with good results. It is only for the first year or so until the tree can get some roots deeper into the soil. I don't mind seeing them at all, knowing it will help keep the trees alive when rainfall is scarce. Lots to think about in your piece, and money is always issue number one in anything publicly financed. But that doesn't mean it cannot be beautiful or appropriate.
    Frances

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  4. Emmat - they were there at the workshop too. And they're most sensible to get the kids involved - Chris Beardshaw said that in his presentation too!

    Hermes - Westminster Council have a budget of £2 million for projects and £3 million for maintenance and they're one of the better financed authorities. There's 106 parks and 3 ce3metaries to look after so the money doesn't go that far, especially when you bear in mind the number of projects most probably is quite small in comparison with the overall number of places to look after.

    Frances - thanks, you have until Saturday, but don't worry any time will do. I'll make sure you get added to the wrap up later if you let me know when you've posted :)

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  5. I've never felt planting Horse-Chestnut trees on the tops of hills where salt breezes shriek in from the sea is a good idea. Seen it and felt sad.

    Don't do too much wrapping, VP.

    Esther

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  6. Hi VP,

    could you explain, please, what 'hollow tined' means? And what on earth the 'rubber crumb' is for? To someone who has never heard of either before, this sounds distinctly odd!

    Thanks in advance

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  7. Yes, what is the rubber crumb FOR? It isn't biodegradeable, is it? For aeration against compaction after too many feet?

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  8. This post is most interesting. I read about what we're doing in plant management in the US, but never hear about it in Britain. I like your way of compiling the report and then using the bullet points.

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  9. Esther - it's crazy isn't it to spend all that money on planting a tree and then for it to die. Trees for Cities mentioned by Emmat are doing text book looking after the trees they've planted. They're making sure that everyone's donations does really make a difference.

    Tony and Elephant's Eye - thanks for reading so far down thearticle and then asking your questions. I ws a bit worried everyone would be put off by the amount I'd written. I'll answer your questions together if I may as they are linked together.

    Hollow tining is a way of lawn aeration (and counteracting the effects of compaction) that's more effective than using a fork. You use something that looks similar to a fork, but each tine looks like a tube. You then spike the lawn and little cores of lawn and soil come out leaving small holes around 4 inches in depth. These holes should then be filled so that aeration continues. The usual filler is sand, but the council are using recycled rubber instead. Now I'm not sure about this because over time there must be a chance that the hollow tining brings up rubber instead of soil. And it doesn't rot down either. I was wondering whether fine grit might be the solution instead if the usual sand isn't good for London's grass. I'll see if I can find a link for hollow tining and insert it into my post just in case others have the same question.

    Mary Delle - thanks. It's the way I used to do things at work and I'm glad it worked for you in here as well :)

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  10. VP Interesting post and how so true the correct planting and follow up are so important and not just with public planting. I have just today moved a young Liquidambar I had not chosen it's site wisely and so something had to be moved now it will be nutruring it through the next couple of years that will be the real test.

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  11. thanks for the explanations. Calling it 'recycled rubber' sounds like a bit of a con to me. Given what they're doing with it, I'd suggest they should call it 'public landfill'! I'm not convinced it's a good idea.

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  12. Joanne - good point, we save ourselves so much work if we get things right in the first place!

    Tony - only too pleased to answer your questions. I've found out there's not a good non-commercial guide to hollow tining, so I've added it to my list for future posts. And thanks for your explanation and link back to here after I left you the explanation over at your place :)

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