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Help! Westringia hedge dying

PostPosted: Wed Feb 26, 2014 9:23 pm
by ArchieBarkatron
Grateful for anyone's help.

I planted a Westringia Wynyabbie Gem hedge from tube stock approx 18 months-2 years ago, at the recommended spacing (can't remember exactly, think it was 40cm or 60cm apart.

A single plant in the middle of the hedge died when they were still young, only about 30cm high, and the two subsequent plants I planted to replace it also died so I didn't bother trying to fix the gap until I could determine the issue. Now the plant directly beside the gap turned yellow and died and I'm a bit worried it's an omen of things to come (the hedge is now approx waist-chest high after I have it a light prune of about 20cm just a fortnight ago). I'll try to attach a pic to assist.

I'm in the western suburbs of Brisbane and the hedge faces approx north west. It is planted in rubbish soil above a retaining wall (ie filled with rocky fill which is why i chose Westringia in the first place, but when I planted each tube originally I put probably a half bucket of native potting mix in each hole to try to help them out). The hedge grew really well until now and I'm a bit late in top pruning it so it's probably not as dense as it could be but otherwise looks great (except the gaping hole). And of course it's been a rough summer in Brisbane.

Please let me know if you think it's dire straits and what I should do. And what else you'd recommend I plant either just in the gap or as a replacement hedge if this one gives up the ghost (I really didn't want murrayas like everyone told me to do but if it's the only thing that will survive... or maybe lomandras).


Re: Help! Westringia hedge dying

PostPosted: Thu Feb 27, 2014 5:58 am
by Pam
When you say 'rubbish soil' is it YOUR rubbish soil, or from another site? If it's from elsewhere it could have anything in it.

First thing to do, I guess would be to dig down a bit to what the roots are growing in and do a ph test so that you know what you're dealing with.

Re: Help! Westringia hedge dying

PostPosted: Thu Feb 27, 2014 2:13 pm
by ArchieBarkatron
Thanks Pam.

It is our 'rubbish' soil from another part of our block. It came from an excavation we did from behind another older retaining wall in our back yard and we then used it to backfill the retaining wall you can see in the picture I attached (it being too costly to pay to have it removed and then to purchase more 'clean' fill). But we found lots of old building materials in that excavated soil so whilst it is from our block, the fill itself is probably not fully reflective of the local soil and was extremely dry and rocky etc. The roots would most definitely be in this 'rubbish' soil as it goes right to the base of the retaining wall (approx 1.5m down). I have had trouble growing a number of natives that in theory should suit the soil and climate and am beginning to think it could be because of the rubbish building materials contained in the soil.

Grevillea Bronze Rambler, banksia integrifolia, an acacia and a few callistemons are really the only ones that have done well but I've still lost even a couple of those (as well as a dianella, brachyscomes, hardenbergias). And other natives planted are still alive but only limping along. Or they do what the westringia is doing - grow like crazy then just keel over.

I must confess I've neglected them with insufficient watering and probably not regular enough native/organic fertilizers but it seems like there's more at play than just that. I'll try your advice re testing the ph if I can but grateful for any suggestions on how to deal with poor soils and if there's any other plants better suited.