Friday, August 10, 2007

To bag or not to bag?

To bag or not to bag - this is the question we ask ourselves each time we plant seedlings at our foreshore project sites. After ten years of experience in our efforts for good plant survival results, the volunteers of Cottesloe Coastcare have learnt about some of the pros and cons of using plant guards.

In a nutshell: we have learnt that plant guards are sometimes required but that weed removal followed by early winter planting gives us the best plant survival results.

We have found that guards are useful:

  • when rabbits are present
  • sometimes to mark out a revegetated area

And guards are not useful if they are:

  • used in shifting sand

  • not well installed

  • not maintained regularly

  • leading to vandalism

  • left on the plants for too long

If you are interested in our experiences click here to read the full article. Included are some website links with further observations.

Also included is a precis of a science research paper by Shane Turner and Bernard McLean of Botanic Gardens and Parks Authority, Perth, WA; 'Optimisation of Greenstock Survival for Restoration of Bold Park'.The study concerns a re-vegetation programme (2002 - 2005), to evaluate site conditions, planting techniques, planting time impacts, the impact of tree guards and weed control on greenstock establishment.

We would appreciate comments from others willing to share their 'bagging' experiences with us. Please add your comment to the blog or email us at:


August 29th -Richard sent this photo of a Banksia which was left in its tree guard for many years!! You will see a note from Richard about the 'to bag or not to bag' question in 'comments'.


Further on the subject of the pros and cons of plant guards. I received the email and photos below on 30th November 2009.

Subject FW: Snake hazard from tree guards

I have wondered about the purpose of the 12 holes in the plastic tree guards. I doubt if they are needed in our climate for reducing humidity. In this case they have killed a dugite.Anyone know of other cases ? It's the first I've seen. Should we use guards without holes ? James

Subject: Snake Date: Sat, 28 Nov 2009 08:52:05 +0800
Hello James, Attached are four photos that I took of the snake. We measured it yesterday when we took the photos. It was hard to get an exact measurement as it was pretty stiff, but somewhere between 49 and 52 cm long Two photos are from outside the plastic bag, and two inside. Richard


Anonymous James said...

Thanks for the article re:plant guards you brought up some very good points which I hadnt thought of.

There are good and bad points for the guards as I have noticed in the bits I've been looking after.

I think some plants really need them and some will do just as well without them.

I've taken some off some of the plants I've planted and it was possibly too early and the weather was still too stormy and they started to get a little weathered and had to be reinstaked (sic)

The sedges only seem to need them for a short period and then do just as well without them, but some of the soft leafy plants need them for a longer period say into the spring and then be removed before summer when the guard may heat the plant and the leaves (burning them).

The issue of maintaining them is important as per the points you raised, ie sand buildup over small plants, or erosion around plant.

I think the guards are useful and should be used in most areas even if only on some of the plants as they provide a very visible indication to the public that the area is being rehabilitated and may stop them from walking over it. Also good PR to show the groups work. It may be useful to review which plants seem to need them and which really dont as this would save unnecessary use and would reduce the amount of ongoing maintenance required.

Where it is necessary to plant a number of plants which require the guards ie to me the leafy ones it may be necessary to only install a limited amount in that area each year so that one or two people could take the role of maintaining them for the period they are in use. This seems to be working for me in the bit I'm looking after.
Cheers, James

6:05 pm  
Anonymous Richard said...

You do have such a great blog; looking at the various details you have exposed in some detail it does appear that bags would only be used where serious rabbit predation is likely on selected species only and to be removed during Spring. The exception might be in a formerly highly trafficked area or to make a particular statement. Thought you might like this bag pic around a very mature Banksia [attenuata?] that has obviously been there many years probably a decade or so and is now literally being split by the tree's trunk!
Happy bagging, Richard.

6:07 pm  
Anonymous Craig said...

To bag, or not to bag? – that is the question.

Craig Wilson
South Metro Coastcare Officer
Swan Catchment Council

The issue of plant bag use is one that is debated by many of the Local Governments and community members in the Coastcare program.
It is the specific situation requirement that determines the decision to install plant bags and this varies greatly according to location and social setting.

The experience of the South Metropolitan Coastcare Program highlights this variability.

Bags are used in the following situations:
•where rabbits are prevalent, bags provide protection from grazing,
•in locations that have a strong community or Local Government maintenance program flapping and collapsed bags are re-staked then removed after the following summer,
•in locations where summer time watering is utilized, bags make it easier to locate plants,
•where weeds are an issue and herbicides are used to provide control bags provide protection from spray drift,

Bags are not used in the following situations:
•Where there is a history of vandalism,
•If there is limited follow up maintenance

In general we tend to use plant bags on the majority of the coastal plantings as there is either a community or Local Government maintenance program that will ensure the bags are kept in place. The positive feedback from the community and Local Government due to their physical presence currently outweighs the negative issues.

10:11 pm  

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