Scottish Rock Garden Club Forum
Cultivation => Cultivation Problems => Topic started by: pehe on July 24, 2009, 08:17:24 AM
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I have brought home some bulbs from Malta in spring 2007. It is Urginea maritima and some narcissus. In autumn 2007 the biggest Urginia flowered without leaves as usual, but leaves have never emerged. The bulbs looks healthy (in 2009), but is apparently sleeping.
The same with the narcissus. The bulbs looks healthy, but no leaves or flowers, only roots.
I grow both in a green house in Denmark to simulate the climate in Malta.
Has anybody an explanation what have gone wrong and how do I wake them?
Poul
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Poul,
Is it possible that by keeping them in a greenhouse you've kept them too warm and they've never got cool enough to trigger growth? Both Urginea and Narcissus grow in the colder months predominantly, so if they never get cool enough is it possible that they would never start into growth? Maybe they think it is an endless summer and that they should stay dormant until it ends? I don't know the climatic seasonal variations in Malta, but I realise somewhat warmer than your own in Denmark, but I am just thinking that the lack of change of seasons within a glasshouse could be the problem? Of course I may be completely wrong. ???
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Paul,
Thank you for your answer.
I had the same idea after the first year without leaves, so the next winter I kept them at a temperature just above freezing point, but still no growth.
In Malta the summer is hot and dry. The winter is wet and average temperature is about 8 degrees.
Poul
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Poul,
Well if you've tried that, then I'm not sure what else to suggest. It certainly sounds like something in the conditions you're providing is somehow keeping the plants mostly dormant, and not triggering the new growth phase, although given that they are producing roots there is SOME growth triggering going on. Strange!!
Hopefully someone else here will come up with the answer. :D
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Poul,
I have no experience with Urginea but daffodils from this area (provided they are the wild growing autumn flowering ones) need a very hot and dry summer rest (best with additional warming during spells of cold weather) followed by decreasing temperatures and watering in autumn - around the beginning of September. I suppose that will suits the Urginea as well.
For the procedure please have a look into Ian Young's Bulb log (http://www.srgc.org.uk/logs/index.php?log=bulb /)!
Gerd
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I have had similar experience with several genera. It may be that the plants need a sudden trigger to initiate growth. This may be a drop in temperature or the introduction of moisture or the two in combination. The good news is that they always did grow again although like Gerd I have no experience with Urginea. Good luck - we look forward to hearing what works!
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The same can happen with Amorphophallus and Hippeastrum, for example I had two pots with five to ten small bulbs of H.petiolatum. I got them dormant last year and planted them. In each of the pots one bulb grows after some weeks, the other ones slept the whole year. I tried it with water, without water, with warm cultivation, with cool cultivation - so success. This spring it happens, nearly from one day to another, that more are growing and in the meantime most of them are green but I can not put my finger on a special change what made them growing.
Also I have some different Amorphophallus. One of them is growing now after 6 month, the others are just sleeping. Until now I only know that they will grow - sooner or later.
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About 10 years ago Alan Edwards gave me a bulb of a nice form of Sternbergia lutea which I planted out in a frame bed. In its first year it produced leaves but no flowers & since then has produced neither. I assumed I had lost it but this year I found a small bulb, still alive. About the same time he gave me a bulb of S.clusiana which has behaved in a similar fashion producing leaves for the first time last year.
I have no idea how one controls the behaviour of these plants.
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Anyone who doesn't like strange features like this in bulbs/corms should definitely avoid some of the Moraea species. I've had bulbs of some of them skip 6 years in a row for now apparent reason. I've grown more of them from seed and thankfully that means there are enough corms that some of them skipping years doesn't matter in the slightest. The original pair of corms are still both there last time I checked, but they only ever came up together the first year, and I have had shoots perhaps 4 years out of the last 10. I assumed until I moved them that I had lost one of the corms, but both corms were there (one now much larger than the other, as it obviously was the one most commonly coming up. The year I moved them the smaller one came up judging from the shoot, and I haven't disturbed them since so I don't know which one of them has come up since then. One has surfaced this year (neither came up last year), so at least something is still there. I have their seedlings flowering for me at the moment though, thankfully. Very, very strange! ::)
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I have a pot of the tetramerous yellow Beauverdia sellowiana originally given to me by Don Elick many years ago. (It's a plant which has been assigned to various genera, including Ipheion, but I throw up my hands in despair at trying to keep up with the botanists and just use the name I received it under.)
After one cold winter 10 or so years ago, it refused to start into growth. For some years thereafter, it remained asleep, the number of corms gradually diminishing. Nothing I tried broke its dormancy. A posting on the PBS mailing list (iirc) suggested that some of these South American amaryllids need a fair amount of heat, so one summer I brought the pot into the house and parked it in a sunny window to bake. Within a couple of weeks it was starting to grow and since then I've been careful to protect it against hard freezes.
It's as though once exposed to cold, it stays dormant until there is a sure sign that warm (recte, seriously hot) weather has returned. And our summer temperatures here are simply not hot enough.
I've seen Ipheion 'Rolf Fiedler' behave in much the same way.
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I have a pot of the tetramerous yellow Beauverdia sellowiana originally given to me by Don Elick many years ago. (It's a plant which has been assigned to various genera, including Ipheion, but I throw up my hands in despair at trying to keep up with the botanists and just use the name I received it under.)
After one cold winter 10 or so years ago, it refused to start into growth. For some years thereafter, it remained asleep, the number of corms gradually diminishing. Nothing I tried broke its dormancy. A posting on the PBS mailing list (iirc) suggested that some of these South American amaryllids need a fair amount of heat, so one summer I brought the pot into the house and parked it in a sunny window to bake. Within a couple of weeks it was starting to grow and since then I've been careful to protect it against hard freezes.
It's as though once exposed to cold, it stays dormant until there is a sure sign that warm (recte, seriously hot) weather has returned. And our summer temperatures here are simply not hot enough.
I've seen Ipheion 'Rolf Fiedler' behave in much the same way.
Just so you can throw up your hands in further despair Rodger according to the Kew checklist it's now Tristagma sellowianum ;D
Late last year or maybe early this year Tony Willis was kind enough to send me a stack of very small bulbils (cormlets?) -if it's any consolation he sticks to Beauverdia sellowiana too!, and having checked that they were winter growers I potted them up in dry compost and intended to leave them until September before watering them. In mid June they sent up shoots without the benefit of water and are now in very healthy growth.
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Gerd, Tony, I will try a really hot summer bake followed by a cooler/wetter period in September to see if that could break dormancy.
Rodger, the temperature was quite low in the first winter, so that could be an explanation of why this long dormancy started.
I have got some usefull advices, thank you all. I will give you a report wether your advises helps(hopefully) or not.
Poul
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Poul,
Please go back in this Forum to : Narcissus miniatus and others / Reply # 56 /
October 21, 2008 ****
Sorry for this late advice - I had difficulties to find my own contribution !
Gerd
edit by Maggi: ****See here for Gerd's post : http://www.srgc.org.uk/smf/index.php?topic=2496.msg59350#msg59350
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Gerd,
What a good idea to give the pots a black topdressing and place them in black lava to secure an extra hot summer bake.
I will try that.
Poul
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Hi Poul,
I'm sorry I don't have any experience on the plants your asked advice for. But I can give 2 different examples:
4 years ago I bought a tropical orchid flower ( holcoglossum kimballianum ). The plant had a flower stem. It never flowered again since this year: I have-at last- a promise of flowers. And I didn't change its cultivation conditions...
5 years ago I purchased a Tropaeolum Beuthii tuber. It grew and flowered ( a little ) only once. The tuber has been repotted recently: still alive and in good health. This species requires a summer dormancy and in spring-apparently-humid& foggy conditions which I certainly haven't been able to give.
Some plants may take a long time ( several years ? ) to acclimatise to the growing conditions we are offering them.
Don't loose hope! and good luck...
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I followed your advice and gave the bulbs a hot dry summer bake. In the beginning of September, after a period with low temperature I started watering.
And with good results! Two of the bulbs have gone out of dormancy and new leaves are emerging.
Thanks for your advices.
Poul
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Congratulations, Poul. I'm glad you sorted it out and got them going. 8)
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Any suggestions for an easy method of dealing with Arisaema bulbs for the winter? Ditto Pinellia. We've taken them out of the old mix but don't care to replant them unless necessary, in which case they'd be kept cold and unwatered.
johnw
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I recently asked this question for some excess arisaema that I don't want to plant yet. I was advised to store them in pots in dry compost but to be planted out by February/March time.
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John,
I think they would all be fine stored dry. Some people store their aroids totally dry and without any mix, watching until they start to naturally shoot then planting them. I know of a few people who realised their Amorphophallus konjac was in flower when they're basement (or office in one case) started to smell like something had died. The Amorph tuber sitting in the cupboard had shot and flowered without soil or water, just sitting on a shelf. They're larger tubers and therefore have more moisture stored, but I wouldn't be too worried about storing the Arisaema or Pinellia either.
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Here is the latest news about my sleeping bulbs from Malta:
All of them are awake!
The 3 Urginea maritime have leaves and all the narcissus (which I believe is tazetta) are visible above ground.
To reward them I have decided to build a small glasshouse in my greenhouse. I can then give them (and my other heat loving bulbs) a minmum temperature of 10 degrees and some extra light too. When you have this high temperature extra light are needed as the light level in my greenhouse is very poor in the winter as it is isolated with some "bubble plastic" to keep it frost free.
Poul
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Good news indeed Poul!
Here's another challenge for all of you - find a way of waking up my tubers of Walleria gracilis. It germinated and grew fine in year one but all tubers have now been fully intact but dormant for 5 years! I've tried hot dry summers, summer watering etc, all with no effect. I almost wish the tubers would rot away rather than torment me like this.
I wondered about trying some ideas such as a VERY warm summer in our 30C incubator at work, smoke treatment etc.
For info, it is a fascinating winter growing little sprawling climber from South Africa , with prickly leaves & stems and scented flowers. There is a picture in Goldblatt & Mannings Encyclopedia of Cape bulbs.
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Darren, it seems others have the same difficulties.... have you seen this post from the pbs archives?.....http://lists.ibiblio.org/pipermail/pbs/2008-October/031812.html
..... it may suggest one answer! :-\
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It does indeed Maggi, thank you! So a long soak in very warm water is the thing to try. Now, where's the Radox...
I'll try this next autumn.
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Last autumn I obtained a couple of bulbs of Narcissus dubius, potted them in my usual Narcissus mix & placed them in an open plunge. Neither broke dormancy so I emailed Paul Christian to ask for suggestions. Here is his reply:
"This species, along with serotinus, elegans and viridiflorus, is notorious for this kind of behaviour and can miss a few years at a time. It frequently then appears without leaves and makes flowers!
It is best treated as if it had leafed up and kept very gently moist, just enough to prevent shrivelling, then given its normal summer rest. In autumn I would inundate with tepid water containing weak, high nitrogen fertiliser, then leave to dry out, then repeat. The inundation and drying coupled with nutrients and the inevitable drop in autumn temperatures is often enough to break dormancy in many of these species that are either arid-land plants or which behave as such.
I am a great fan of planting our rather than potting and we grow very very little in pots now."
I'll try this next Autumn.
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Hi,
As I live in a climate which has seriously hot dry summers I haven't yet had any experience with bulbs suffering extended dormancy but perhaps my observations based on temperatures may assist.
I have Urginia maritima and a range of autumn-winter growing Mediterranean climate species growing in the garden. The dry hot summer rest is much hotter than 30deg C we get at least three weeks where the temperatures are 35deg +. Usually we get cooler intervals of 28 to 30 deg in between a couple of days above 35deg. I guess the point I'm trying to make is for some of these bulbs 30 deg may not be hot enough.
The other thing that I've noticed is that the U. maritima comes up in late summer, often while it is still hot in February 40C + days are not unusual, but I have noticed that U. maritima and some South African species start to move when we move to autumn patterns and the night time temps drop. For example yesterday was 32C and the night was 14C. I wonder if this disparity between days and nights could be some kind of trigger telling the plants that winter rains are not far off and its time to do their thing.
Perhaps in homes and greenhouses the temperature fluctuations are less dramatic and the plants therefore sit tight waiting for nature to tell them its autumn.. i.e. warm days and cool nights.
Cheers Anita
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That is interesting thank you. I've got a Narcissus broussonetii that has slept for two years, I'll have to make sure it gets a bit more heat this summer.