Scottish Rock Garden Club Forum
General Subjects => Flowers and Foliage Now => Topic started by: Dionysia on December 03, 2015, 12:49:42 PM
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Many plants produce precocious (early) flowers during autumn, I have found this to be a particular problem with Dionysias. This year has been especially bad; I am having to remove several dozen flowers every day. I've always clung to the hope that by preventing flowering, they will flower fully in the spring, they do certainly produce more than one flower per rosette. The main reason however and the reason I have posted this for newer growers is as a warning not to be tempted to leave them in place as the consequences can be severe. Precocious flowers do not last as long and can quickly become damp leading to rot transferring into the rosette. I remove flowers as soon as the corolla opens, all the flowers on the attached photos opened overnight and there will be at least as many again tomorrow.
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My goodness Paul - there are a lot of flowers - I imagined there might only be one or two - that is more flowers than many ever get!
Very timely warning you make about the dangers of mould /botrytis on the spent flowers - it is always astonishing how fast these infections can occur on, for instance, Crocus flowers.
Close examination of the plants and timely action is great advice.
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Yes Maggi, I'm prepared to accept being called paranoid for checking every day but it is prudent as botrytis only needs one foot in the door to run rampant and this is the worst time of year when the weather is as mild and wet as it is down here in the banana belt. The only saving grace is that it has been very windy for a couple of weeks now.
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... that is more flowers than many ever get!
Oh so true, unfortunately :P
Wonderfully grown plants Paul, and a timely caution. Before the recent windy period even developing shoot tips of tropaeolums were attacked by botrytis in my greenhouse despite all windows and doors at both ends fully open :o The problem has been unusually acute this year.
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I believe botrytis is probably the most serious problem that affects our plants - it is a constant task to be aware. And that's without being in the banana belt! ;D
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Thanks for posting this useful warning Paul.
As a rank amateur enchanted by the beauty of Dionysia I have managed to acquire a handful of tiny plants of a few species.
D. janthina had grown well with me through the summer increasing in size fourfold. A few weeks back it produced a handful of flowers which I admired .....and left. I have a long working day & so my alpine house is unattended for 4-5 days at a time. Recent mild very humid weather with frequent haars (a local term for mists arising from the nearby Firth of Forth) have been an issue and so I was horrified to find a fur-coat of botrytis encasing my janthina having spread out from a spent flower. The rate at which this botrytis developed and spread is breathtaking!
In the coming year I will acquire a new greenhouse -is there any advice you can give regarding "infrastructure" which will help me grow these plants? Is there any "prophylactic" treatment that will help protect dionysia cushions from botrytis attack?
Once I improve my "growing environment" I will need to track down a source for new plants; they are rather scarce on Scottish nursery lists! ;)
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Unfortunately due to the intervention of our beloved EU there are no effective botrytis controls for the amateur grower. Ventilation is the most effective control. I leave all windows open except when rain is wind driven and even then they're open a crack. Some of the glass panes are replaced by wire mesh but where these are above bench height I have rigged up polycarbonate canopies to (hopefully) prevent rain ingress. Likewise doors are open except in driving rain and even then the bottom panes of glass (below bench height) are replaced by wire mesh.
Having said all that, fog or haar is clearly not kept out by this so in the event of fog I do close the doors and windows and rely on the fans to try and at least keep the air a bit buoyant. I have one 12 inch fan in each greenhouse and they last at least three or four years despite being on 24/7/365. If you're reading this Jon (Evans) the one that gave up when we were discussing it during your recent visit, woke up the following day and is still running.
Sorry about your janthina Steve. As you say, you admired the flowers and left them. I'm sorry I didn't post this warning earlier. Of course not everyone has as much time as me; check as often as you are able and remove any autumn flowers as soon as you can get a grip on the whole flower, make sure you don't leave the tube as this is enough to start the rot. You may need to do this before the flowers actually open if on a tight schedule.
There aren't many commercial sources of Dionysias. I do sometimes have spares for the AGS sales tables but we rarely venture far north enough to attend joint AGS/SRGC shows. Your best bet is probably Aberconwy; they have plants propagated from material from me and other growers.
More info can be found in an article I wrote in the September 2008 AGS bulletin.
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Not perhaps in the same league as Dio0nysias, but the same warning also applies to Show Auriculas. The flowers on them which appear now are incredibly prone to Botrytis which even more quickly spreads down the stem and rots the rosette.
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Many years ago when I used to grow dionysias when there were only a handful of species in cultivation and I am sure Paul will remember I actually showed janthina in flower at one of the autumn shows it then proceeded to die. I wonder if the clone in cultivation now is still the original or a later introduction. Another species that always flowered and died was denticulata which I managed to keep for four years once by removing the flowers and I wonder Paul is it still in cultivation? .
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Hi Pat, good to see the magic is still there! You're quite right, janthina and denticulata were always amongst the most temperamental. Janthina frequently flowered better in autumn than spring and to quote Chris Norton denticulata usually flowered at Christmas then died. The original clone of denticulata, GW/H674 did possibly die out in the UK but Marika from Gothenburg was kind enough to let me have a new plant last spring. So far I've only had to remove a couple of flowers from this. There is another plant purporting to be denticulata going the rounds that has come from the continent but I'm certain it's a hybrid with tapetodes as it looks nothing like denticulata and there are no other clones in cultivation. It was not recollected by any of the expeditions since the turn of the century.
The clone of janthina which you grew, JCA2806, is still in cultivation although I don't currently have it, although I do have two more recent introductions, SLIZE265 and T4Z007. You did well to flower janthina well enough to show as I have never found any clones to be particularly free flowering, whatever the season. I do also recall the late Chas Carter showing a large, relatively well flowered specimen around ten years ago.
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Thanks for the info Paul and when I see your plants and indeed nigels I sometimes miss it but not for long. If you ever decide to grow cyclamen let me know I can give you a head start. Looking forward to seeing your plants in the spring if only from the show reports.
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Thanks Pat. I do grow a few Cyclamen but more for the multi pans as I can't grow them like you and Ian Robertson amongst others. From what I have heard of next years show schedule, we're going to have to travel further in March to find a show and as for the curtailment of show reports, well don't get me going. Not popular south of the border apparently.
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Unfortunately due to the intervention of our beloved EU there are no effective botrytis controls for the amateur grower. Ventilation is the most effective control.
Does sulphur help - or does that only control other types of fungi?
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Hi Mark
I do sometimes drop a bit of yellow sulphur in a hole left by a removed rosette. I'm not convinced of its effectiveness however but it certainly does no harm. Need to be careful not to spill it on the surface as it can leave a mark. I've also tried cinnamon following a tip but again cannot be sure of any benefit.
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Paul - could you post some pictures of the fans - I have lost a couple of dionysia this year and it is really frustrating - I only get in that alpine house once a week and by that time its usually too late
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Graeme, they're basic 3 speed 12 inch desk fans that you can buy at DIY stores and similar. They can be difficult to find in the winter as they're seasonal for most users but I did recently buy a couple of back ups off Amazon, just in case one breaks down this winter.
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thanks Paul, I'm not growing Dionysias but sometimes have similar types of issues with the few things I do grow like Primula allionii - I did have one very nice plant which was completely covered in flowers - it must have sweated underneath because I then lost almost all of it to rot - this was before any flowers faded.
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Paul - could you post some pictures of the fans - I have lost a couple of dionysia this year and it is really frustrating - I only get in that alpine house once a week and by that time its usually too late
I'm not sure how long this eBay link will last but I have found these fans to be very useful: http://www.ebay.co.uk/itm/Clip-on-air-fan-circulator-cooler-hydroponic-grow-room-tent-office-desk-fan-6-/390705242971?hash=item5af7d8e35b:g:nykAAOSwuWVWFS6s (http://www.ebay.co.uk/itm/Clip-on-air-fan-circulator-cooler-hydroponic-grow-room-tent-office-desk-fan-6-/390705242971?hash=item5af7d8e35b:g:nykAAOSwuWVWFS6s)
They easily clip onto internal framework in the greenhouse, are surprisingly resistant to humidity and whilst having a low power consumption produce good airflow. I have used these types of fan on Ophrys and South African amaryllids in a greenhouse extension which has poor ventilation (to conserve heat). It is best to purchase a few and place them such that there are "criss-crossing" airflows -the swirling and airflow interference patterns ensure excellent air movement. Mine are controlled by a plug-in timer (has the facility to switch on/off in 15 minute increments over 24 hr). I am only now using these fans on cushion plants in the "open" alpine house but despite the continuing unseasonably mild temperatures with excessively high humidity I have been able to halt the spread of botrytis on my small collection of Dionysias.
Another more expensive option is to use a dessicant dehumidifier. These have only recently become available at an affordable price. Basically the technology is based on humid air being sucked in over a zeolite disc which very effectively absorbs the moisture and is then "recharged" by a small heating element in a regular cycle. A cheap unit will cost about £130+ but can effectively remove 8L of water per day -more than enough for a large greenhouse. Unlike compressor dehumidifiers these units remain efficient even at low temperatures.
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Those SwiftAir fans are available via the Amazon link at the foot of SRGC pages :
http://www.amazon.co.uk/QUALITY-Office-Hydrophonics-Cooling-Fans4less/dp/B00EUZB4JW/ref=sr_1_fkmr1_1?ie=UTF8&qid=1449782493&sr=8-1-fkmr1&keywords=SwiftAir+clip-on+electric+fan (http://www.amazon.co.uk/QUALITY-Office-Hydrophonics-Cooling-Fans4less/dp/B00EUZB4JW/ref=sr_1_fkmr1_1?ie=UTF8&qid=1449782493&sr=8-1-fkmr1&keywords=SwiftAir+clip-on+electric+fan)
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Good to see further tips being given. I adopt a lower tech method of reducing moisture. Every morning I check for condensation on the windows and remove with a Kärcher window cleaner. Only realistic if you're retired with a tolerant spouse.
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Another more expensive option is to use a dessicant dehumidifier. These have only recently become available at an affordable price. Basically the technology is based on humid air being sucked in over a zeolite disc which very effectively absorbs the moisture and is then "recharged" by a small heating element in a regular cycle. A cheap unit will cost about £130+ but can effectively remove 8L of water per day -more than enough for a large greenhouse. Unlike compressor dehumidifiers these units remain efficient even at low temperatures.
Have got one of these in a shed somewhere - I bought a battered second hand one when we were trying to dry out the plastering in the house - I had never ever considered using it in one of the alpine houses - thanks
The fans look good too - I had been looking at ones which look like a drum and hang from the ridge bar - but they get in way or the lighting
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Another good source of desk fans is to find your local auction house that deals in the bottom end of the auction market. You can usually get working 12" fans for about £5
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Thank you for this thread.
As someone who is slowly building up a collection of winter flowering Salvia it is something that I am vigilant towards. Thankfully so far this year the greenhouse door and windows have barely been shut which helps but I have been extra cautious too. I wipe the glass down at least once a day with workshop paper towel and have newspaper on all flat surfaces which is chucked every two or three days - small measures which offer small but useful benefits. The hardest part was leaving all my Echium seedlings outdoors as they all exhibited signs of infection as early as October outdoors.
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just to add I've started using a dehumdifier which started after a decade to become too noisy for the house. Of course now it is out in the greenhouse it is silent. I've run it on foggy days but so far haven't been able to do enough measures to see what the effect on humidity is. It does put out some heat which is ok for me as most of the my plants are cyclamen but might be an issue for others.
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I am rather fearful of mains electricity in a glasshouse. At one time I thought of getting an electric fan from a car and connecting it up to a twelve volt battery in a garden shed and keeping it topped up with a mains battery charger. A cable carrying 12V would not present any danger. I think it would work but have yet to get round to it....like most other ideas !
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I had an electrician wire it up. From the house with armoured cable, to the garage with a seperate fuse set to the greenhouse with plenty of power available for heaters, light, fans etc.
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I did the same in the polytunnel.
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I have 20 feet of armoured cable left over from the wiring job to my shed. I have a consumer box fitted with two ring circuits and lighting circuit.
I have fitted a PIR controlled lamp connected to the ring circuit with a weatherproof outside switch. Fitting the electrics does not bother me but routing out a channel in the concrete base for the armoured cable seems too much of a bother. Anyway, the costs of electricity would put me off.
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My builders overcame that little problem by bringing the armoured cable up just short of the base and mounting a double outdoor switch on a 4x4 post. An appropriate extension lead is then used to route the power in via one of my louvre panels, with a suitable drip loop of course.