Romneya coulteri

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JTh

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Romneya coulteri
« on: June 16, 2011, 10:34:54 AM »
I saw a plant with large flowers in Southern California a couple of weeks ago, both in the wild in a mountainous area between Murrieta (near San Diego) and San Clemente and in a garden belonging to Mission San Juan Capistrano. It looked like a giant poppy, and I had planned to post some photos here for identification. In the meanwhile I found the name of the plant in a book, so it is no longer a mystery to me, but I am showing it anyhow, since it was quite striking, with many large (around 15 cm), fragrant, white flowers, the whole plant was more than 1 m (said to be up to 2.4 m) tall, gray-green pinnately divided leaves. The name? Matilija Poppy (Romneya coulteri).  
« Last Edit: March 11, 2012, 09:28:51 AM by Alisdair »
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

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Alisdair

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Re: Californian poppy
« Reply #1 on: June 16, 2011, 03:22:21 PM »
Super pictures, Jorun! It is indeed a lovely plant.
Romneya coulteri can be invasive in mediterranean climates, particularly in light or rocky soils, eventually forming large dense clumps and growing well over head-high. This may suit large semi-wild gardens well, but perhaps not smaller ones.
It is much better behaved in conditions that it finds more difficult - less warmth in summer, heavy poorly drained soil. For years we have had a clump on a south-facing bank in our Sussex (UK) garden, on clay, where it will flower later this month. It has frost down to -10 deg C in winter, and the heavy soil can get very wet. So it has never got much taller than a metre or so in height, and never spread too much. But I don't dare plant it in our Greek garden!
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society

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JTh

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Re: Californian poppy
« Reply #2 on: June 16, 2011, 07:53:06 PM »
Thanks for the useful warning, maybe I could try it here in Norway, the winter is cold enough here and the soil in my garden is very clayey.
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

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John

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Re: Californian poppy
« Reply #3 on: June 21, 2011, 10:17:34 AM »
Many years ago I saw this plants at Hadspen where it had completely taken over part of the garden. They had to clear the whole area to get rid of it as it is so invasive. Though very beautiful. I have also heard of it invading a house wall cavity where it appeared in the roof! So be warned.
John
Horticulturist, photographer, author, garden designer and plant breeder; MGS member and RHS committee member. I garden at home in SW London and also at work in South London.

Chantal

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Romneya coulteri seeds
« Reply #4 on: July 02, 2011, 07:30:54 AM »
As my Romneya coulteri set a lot of flowers this year - flowering time was early this year - I would like to collect and keep the seeds for our seed list.
At what time and how can I collect the seeds ? The seed pods seem to be prickly. Do I wait for them to become brownish ?

Thank you for any advice
Chantal Guiraud
Montpellier-France
MGS Seed Coordinator

"The flowers of spring are winter's dreams told in the morning at the table of the angels" (Khalil Gibran)

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JTh

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Re: Romneya coulteri seeds
« Reply #5 on: July 06, 2011, 01:58:32 PM »
There are many links on the internet about starting this froms seeds, they all say that it is difficult, and that  seeds are only likely to germinate in media treated with smoke. Nitrite from combustion products has been identified as the primary germination trigger; not heat or ash. See http://www.ehow.com/how_7380_grow-matilija-poppy.html,  http://www.alchemy-works.com/romneya_coulteri.html or http://davesgarden.com/guides/pf/go/2504/.
I have also read that you should start the plants from seed in the autumn, which means that the seeds need to be fully mature before you collect them.
Did you see Alisdair's warning about this plants in the post I started about this plant some weeks ago (under wild plants - species seen- Californian poppies)? It may be invasive.
« Last Edit: July 06, 2011, 04:36:59 PM by Alisdair »
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

Chantal

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Re: Romneya coulteri seeds
« Reply #6 on: July 07, 2011, 07:16:52 AM »
Yes, I know it can be invasive, but as usual, I don't take care and surely, within a few years, I will have to do something to prevent it from smothering the neighbours.
I am just asking how can I see the seeds are mature ? I suppose they are tiny things.
How much under zero can you get in winter in Norway ? Because, in my previous garden close to Paris, I had it and it was very invasive too, but I like it, and my friends were very jealous about my plant.

Chantal Guiraud
Montpellier-France
MGS Seed Coordinator

"The flowers of spring are winter's dreams told in the morning at the table of the angels" (Khalil Gibran)

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JTh

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Re: Romneya coulteri seeds
« Reply #7 on: July 07, 2011, 10:07:03 PM »
I don't think it would be invasive in Norway, if it would survive at all, we had more than two months with temperatures between -15 and -26 ˚C last winter in Oslo. I would love to try it here in northern Greece, I thought it was very specail as well when I saw it in California this spring. I would guess the seeds are ripe when the capsule is dry, like other poppies.
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

Chantal

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Re: Romneya coulteri seeds
« Reply #8 on: July 09, 2011, 07:46:38 AM »
Thank you Jorun, I suppose so, too. Anyway, I'll wait till september before harvesting them.
Chantal Guiraud
Montpellier-France
MGS Seed Coordinator

"The flowers of spring are winter's dreams told in the morning at the table of the angels" (Khalil Gibran)

Umbrian

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Re: Romneya coulteri seeds
« Reply #9 on: July 21, 2011, 02:41:26 PM »
If only I could get this wonderful plant to invade my garden! In England I first saw it growing from between the cracks of some paving outside a cottage in a village near to me - it had "travelled" from the garden behind. I eventually did manage to establish it in my garden there but have had no luck since moving to Italy. Two, very expensive, plants did not even see the year out. I did manage to get some seeds to germinate (in England) but even though they appeared to be strong and healthy they soon keeled over when planted in the garden. I am told the reason for it always commanding a high price is that it is notoriously difficult to propagate - quite a paradox when in some places it is considered invasive.
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.

Chantal

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Re: Romneya coulteri seeds
« Reply #10 on: July 23, 2011, 01:53:13 PM »
I had 50% good results when I divided the roots in february. I cut big pieces of root (around 10 cms long) and planted them in big containers in normal soil well drained. The trick is at the plantation in situ. When they have rooted just cut the bottom of the pot and plant it with the pot, so you don't disturb the roots at all.
Good luck
Chantal Guiraud
Montpellier-France
MGS Seed Coordinator

"The flowers of spring are winter's dreams told in the morning at the table of the angels" (Khalil Gibran)

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John

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Re: Romneya coulteri
« Reply #11 on: March 13, 2012, 09:42:36 AM »
I saw the reply to Umbrian's comment about Romneya under Ebenus cretica and Jth pointed her to the subject here, under herbaceous. Surely Romneya coulteri is a shrub? It always has been in my experience though I can see that their suckering habit may confuse this.
John
Horticulturist, photographer, author, garden designer and plant breeder; MGS member and RHS committee member. I garden at home in SW London and also at work in South London.

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John

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Re: Romneya coulteri
« Reply #12 on: March 13, 2012, 09:45:31 AM »
I have just re-read the previous comments and though I no longer have it in the garden I seem to remember that it never set viable seed. I don't know the reason unless you need two clones to get seed set?
John
Horticulturist, photographer, author, garden designer and plant breeder; MGS member and RHS committee member. I garden at home in SW London and also at work in South London.

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Alisdair

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Re: Romneya coulteri
« Reply #13 on: March 13, 2012, 10:34:07 AM »
John, Of course you're right about its habit - it is indeed a shrub or at least sub-shrub. So I'm moving this thread to the Trees and shrubs section.
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society

Umbrian

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Re: Romneya coulteri
« Reply #14 on: March 14, 2012, 07:04:36 AM »
Old age creeping on apace - I had quite forgotten my previous posting about Romneya and the interesting replies it received  ::) If I manage to find a reasonably priced one this spring I shall follow the advice to plant the whole pot in situ and see if that is successful. I have plenty of space for it to romp about in, if only it would, I just love the beautiful white flowers and the glaucous foliage- a real show stopper of a plant in my eyes but agree it could be a severe problem in a small garden.
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.