The MGS Forum
Plants for mediterranean gardens => Trees and Shrubs => Topic started by: JTh on June 16, 2011, 10:34:54 AM
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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).
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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!
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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.
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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.
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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
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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 (http://www.mgsforum.org/smf/index.php?topic=32.msg48#msg48) 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.
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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.
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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.
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Thank you Jorun, I suppose so, too. Anyway, I'll wait till september before harvesting them.
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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.
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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
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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.
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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?
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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.
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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.
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This is one of my favourite plants. I brought a Romneya coulteri from England many years ago and planted it in my Garden in the Southern Peloponnese. It grew to height of 1.6m and formed a clump roughly 1.2m in diameter, but was not inclined to become invasive. This may be due to the altitude of the garden - 450m above sea level with occasional winter frosts, or the soil - stony clay. I have since moved, and would love to have another, but have yet to find a source; I've had no success with seeds.
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Did you water it at all in the summer, KatG?
Some UK nurseries do sell R. coulteri and ship to Europe, but that is expensive. For instance you could ask Burncoose for an estimate - their email is info@burncoose.co.uk.
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I bought my Romneya at Beth Chatto Gardens last May and brought it down to Spain subsequently. Having gingerly planted it as I heard that roots must not be disturbed at all...its now seems to be doing very well and I have noticed a small seedling on the side of the main plant. I am not expecting it to flower this year as I often find plants take at least two seasons to settle in and flower here on our chalky soil. That being said I would love it be invasive, its such a glorious plant! Nothing but nothing is invasive and uncontrollable in my garden except oxalis and I have discussed this at length.
April is here and our Echiums are amazing, all shades of pale blue, deep blue though to mauve and they look spectacular..such a lovely month for Echiums.......A great plant for dry gardens.
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Unfortunately Beth Chatto don't export - great if you can collect.
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Alisdair, I planted it roughly 15 years ago so I don't remember exactly what sort of watering regime it had. I'm sure I hand watered it for the first summer, but I don't think it had any additional watering after that.
Thanks for the Burncoose info.
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Thanks, Kat; we've got a patch here in Sussex which has been very gently and modestly increasing over the last 15 years, and I've been wondering about perhaps taking a piece out to Greece this autumn - you've just about convinced me to try it!
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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.
This is my first posting so please excuse the nature of it. It is a plea for help. I do love this plant but unfortunately I think I need to kill it because it is seriously invading our house. It is entering under thick stone walls and passing under the plastic damp proof membrane below our flooring.
It first appeared sprouting from behind the skirting board about 15 feet into our house relative to the outside world. We tried Weedol and Roundup on it but it grew back just as vigorously.
More recently we noticed cracking and bulging of an internal plasterboarded wall extending up to ceiling height. I then broke open the plasterboard to discover that it was just on the point of invading the room above.
Clearly we will need to pull up the floor and DPM to dig it out and I think we really can't trust it not to invade us again so I suspect that we will need some serious excavation of our garden and its walls. (It has already gone beneath our 7 foot stone wall into our neighbour's garden)
Even if we do attempt to remove all its root system I think there is a very good chance that we will not manage to catch it all. For this reason I would like to poison it and hope that you might be able to suggest an effective poison.
Peter.
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Hello Peter, gosh, what a mess. This year I bought a plant of R.coulteri at the Lucca show Murabilia. The nurseryman warned me that it is invasive and he had seen it invade a bathroom. I almost did not believe him, now I do. I live in Toscana and if I had your problem I would take advice from the local Agraria, roughly, farm supply shop. They have visiting agronomists who are only too happy to give advice and to sell their products. Usually I avoid them as they are too heavy handed, but this requires firm treatment. Let us know how you get on.
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Hello Joanna,
Thanks for your Agraria suggestion. We would certainly like guidance from someone with experience of this type of problem and we were unsure who to contact. I will let you know how we get on.