rosemary dieback

  • 16 Replies
  • 19662 Views
*

MikeHardman

  • Hero Member
    • www.mikehardman.com
rosemary dieback
« on: June 04, 2012, 09:50:22 PM »
Some of my rosemary 'Haifa' (prostrate) plants have developed dead branches in recent weeks; see photo.

I now find there is such a thing as 'rosemary dieback'
(eg. http://xtremehorticulture.blogspot.com/2012/04/rosemary-bush-very-susceptible-to.html)
I have to presume that is what my plants have.
(I have examined affected branches in cross section and can find no trace of stem borers, as an alternative explanation, for example.)

When I planted them, I made the usual little depression/wall in the soil around the plants to help keep the irrigation water where it was intended to go. That obviously left them prone to conditions favouring rosemary dieback - as the depression fills up with soil the stem gets buried a little. Wish I'd known about that sooner!

I am cutting out the affected branches, and hoping that the plants recover. At least, being prostrate and rooting as it goes, it is not reliant on just one stem, as an upright plant would be.

Any comments appreciated.
« Last Edit: June 04, 2012, 09:52:32 PM by MikeHardman »
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

Umbrian

  • Hero Member
    • Email
Re: rosemary dieback
« Reply #1 on: June 05, 2012, 05:58:34 AM »
As the rest of the branches look very green and healthy Mike I would think they will be OK. I have had this at times with some of mine and have just cut out the dead bits with good results. :)
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

*

MikeHardman

  • Hero Member
    • www.mikehardman.com
Re: rosemary dieback
« Reply #2 on: June 05, 2012, 07:08:56 AM »
That's good to hear, Umbrian - thanks.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

David Bracey

  • Hero Member
    • Email
Re: rosemary dieback
« Reply #3 on: June 05, 2012, 07:44:31 AM »
Mike as your article says they suffer from Collar rot which is a Phytopthora cactorum (possibly) (hope it's splet correctly) which is a soil borne disease along with several others.

Did you put any compost etc in the planting hole.  Trouble with the depression-type planting is that is that it is rule of thumb ............but what is the rule? Do not over water.

As Umbrian advises prune back to some healthy rooted shoots.
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

*

MikeHardman

  • Hero Member
    • www.mikehardman.com
Re: rosemary dieback
« Reply #4 on: June 05, 2012, 08:35:51 AM »
Thanks David.
The plants did not get any compost from me when I planted them. But they were still in their original nursery-supplied compost - which was typically peaty/organic. Since then (a year ago), they will have dropped a fair amount of leaf litter, hence adding organic content.
I have turned the irrigation off now.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

june grindley

  • Newbie
Re: rosemary dieback
« Reply #5 on: October 30, 2012, 12:51:07 PM »
Dear Mike,
My creeping rosemary has also died back in the centre. What happened when you cut yours back - did it recover? thanks, June Grindley

*

MikeHardman

  • Hero Member
    • www.mikehardman.com
Re: rosemary dieback
« Reply #6 on: October 30, 2012, 02:37:21 PM »
June - yes - recovered. In fact, I can't find the dead spot now because it is overgrown with new shoots.
Another plant from the same batch, planted nearby, has recently had a small bit of die-back, though.

If one had just a single plant that was dying-back, I'd suggest finding rooted shoots away from the brown patch, severing them, and planting them somewhere else (preferably with a bit of a slope to ensure they don't sit with stems in water). In planting them, I'd cut back the top growth a bit (depending on how much root it had), and putting a stone ontop of the rooted portion (to help anchor it and to retain dampness). I would remove the stone before too long, though; else the die-back might strike again. I'm still gaining experience of this issue, so these are not expert words, just my thoughts.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

june grindley

  • Newbie
Re: rosemary dieback
« Reply #7 on: November 03, 2012, 02:43:14 PM »
Thanks Mike for the encouraging words and suggestions. Unfortunately the rosemary in question is quite big with a huge area of dieback surrounded with a small halo of green!  I'll try cutting bits back but I'm afraid it may have to go. Replanting the dead centre with new cuttings is not an option because I cannot get to the centre easily without chopping it hard back.  Any ideas for replacing it? (We are only here half the yr and get frosts plus three month's summer drought!!!0

*

MikeHardman

  • Hero Member
    • www.mikehardman.com
Re: rosemary dieback
« Reply #8 on: November 03, 2012, 04:31:06 PM »
Oh well, yes - sounds like it'll have to go.
As for replacing it, I think it depends what function(s) it has to serve: colour/screening/bee-fodder/etc. If it needs to be self-sufficient, I'd first look at native species, and especially ones in the area (same microclimate and soil). Reckon on starting with a small specimen and thereby allowing it to develop a deep root system at the same time as the top-growth enlarges. It'll be more resilient to drought and wind that way.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

pamela

  • Sr. Member
Re: rosemary dieback
« Reply #9 on: November 03, 2012, 07:57:23 PM »
June what about Westringia fruticosa?  Fantastic plant for absent gardeners.
It looks a bit like rosemary and very pretty.
Jávea, Costa Blanca, Spain
Min temp 5c max temp 38c  Rainfall 550 mm 

"Who passes by sees the leaves;
 Who asks, sees the roots."
     - Charcoal Seller, Madagascar

Alice

  • Hero Member
Re: rosemary dieback
« Reply #10 on: November 03, 2012, 08:27:00 PM »
I would second Pamela's suggestion. Westringia fruticosa is a rosemary look-alike and keeps its shape much better.
Amateur gardener who has gardened in north London and now gardens part of the year on the Cycladic island of Paros. Conditions: coastal, windy, annual rainfall 350mm, temp 0-35 degrees C.

june grindley

  • Newbie
Re: rosemary dieback
« Reply #11 on: November 05, 2012, 04:00:22 PM »
Dear All,
Thank you for suggestions to replace the poor rosemary. I have tried Westeringia here but it grows very slowly and I'm not sure that it is frost-hardy enough for our winters. I really need something that will cover the ground quickly and stabilise the slope in full sun!!! It's a hard location to fill!
best regards, June

*

Fleur Pavlidis

  • Global Moderator
  • Hero Member
Re: rosemary dieback
« Reply #12 on: November 06, 2012, 08:58:22 AM »
Please don't give up on rosemary. There are upwards of thirty named varities to try and they all have different growth habits. I have many prostrate ones and they have never collapsed in the way that the more upright ones do when they get a bit old and they grow back over injury. If you consult O Filippi's online catalogue he describes the way each variety grows. The two types of rosemary in the pictures are locally bought, different but un-named. The first one hasn't been pruned back for a couple of years, the second was chopped back from the path last autumn. I also dug out a big weed from the middle of it and quite spoiled the shape, but as you can see it has grown over the wound very quickly. I'd dispense with the old and try some new.
MGS member, Greece. I garden in Attica, Greece and Mt Goulinas (450m) Central Greece

Umbrian

  • Hero Member
    • Email
Re: rosemary dieback
« Reply #13 on: November 07, 2012, 08:14:50 AM »
I agree, don't give up on Rosemary but I must mention again the ground covering capability of Junipers. I planted some small specimins of a prostrate form (cannot tell you the exact cultivar since ,as is nearly always the case here, the plants had no proper labels) when planning the long border beyond our pool. I wanted something towards the back that was green and pleasant to look at even in the winter when the more showy things had finished and been cut back. The soil is terrible, sub-soil in the main from the pool excavation and the border in full sun for most of the day. The Junipers have flourished though after taking a little time to get going - spreading branches root where they touch the ground ensuring that the plants stay healthy looking all through the year. In fact they have been so successful that now I have to trim them back every year to prevent them engulfing too many other things. To the back of the border they have surrounded the shrubs I planted ,to no ill effect ,and are gradually covering the area behind that slopes away - beyond all my expectations and a real bonus as this is where my wilder, less cared for garden begins. To the front I have created a wavy line that in itself is very pleasing curving around groups of lavender and gaura. Long extensions cut carefully when doing this work can be planted elsewhere and I have great success with these too with the minimum of care and given them to friends who have admired the original planting,
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

june grindley

  • Newbie
Re: rosemary dieback
« Reply #14 on: November 07, 2012, 04:27:57 PM »
Brilliant ideas and suggestions, Rosemary and Fleur. thank you best regards, june