Precocious flowering - a warning

[Dionysia]

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. 

[Maggi Young]

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.

[Dionysia]

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.

[ashley]

... that is more flowers than many ever get!

Oh so true, unfortunately

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   The problem has been unusually acute this year.

[Maggi Young]

 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! 

[Steve Garvie]

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!   

[Dionysia]

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.

[Palustris]

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.

[cycnich]

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? .

[Dionysia]

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.

[cycnich]

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.

[Dionysia]

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.

[Mark Griffiths]

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?

[Dionysia]

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.

[Graeme]

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