Encouraging terrestrial orchids to increase vegetatively

[Tristan_He]

Hi Orchid lovers,

I have a query about this. I recall somewhere reading about a technique to encourage terrestrial orchids to bulk up. I can't remember if this is exactly right but from memory it was by knocking them out of their pots while in growth, cutting off the newly developing tuber and replanting both the plant with the old tuber still attached and the newly developing tuber. But now I can't find any information.

Did I imagine this, or is it a recognised method? And if so, what is the correct method and when is the best time to do it? I don't want to start hacking randomly at my orchids without knowing what I am doing.

Thanks!
Tristan

[Anders]

Certainly a recognised method. It is described in detail in Cribb and Bailes, 1989, Hardy Orchids - Orchids for the garden and frost-free greenhouse. Page 43: "Summer propagation. The method is used just as the flowers begin to fade (which will be any time from early spring onwards, depending on the plants being grown, and the conditions under which they are housed). Remove the plant from its pot and separate the new tuber from its rosette by cutting the stolon, or at the place of attachment, The rosette and old tuber,  which should have most of the root system intact, should then be repotted in the normal way, as should the new tuber. Aftercare of the two differs. The new tuber should immediately be treated as if dormant, whilst the flowered shoot and old tuber should be kept in growth for as long as possible, to allow the maximum opportunity for new tubers to develop before dormancy.  Do not allow seed set, or the rosette will die off more rapidly, and reserves will be taken from tuber production to seed production. Shady, moist conditions will delay dormancy in those species which are summer, or dry season resters. After the rosette has died down, give the normal conditions for rest, and thereafter treat normally".

Ian showed how to do this for Dactylorhiza in his Bulblog a few years ago. I tried it with several Dacts with good results. You don't need to cut them with a knife, the old and new tubers separate easily with a little twist. Btw,  the Cribb and Bailes book is the best hardy orchid book, if you ask me.

Anders

[Tristan_He]

Thanks very much Anders! I thought I had read this somewhere. I'll give it a try in the spring.

[Maggi Young]

From the  Forum : "The technique used for dactylorhiza can be applied to certain Orchis and Ophrys species " quote  from Hristo ( C. Greenwell)  in 2009

Method described  in Ian's  Bulb Log

http://www.srgc.org.uk/logs/logdir/2015Sep161442400879BULB_LOG_3715.pdf

Videos parts  1 2  and 3 





part three of the Dactylorhiza method.



In this  Bulb Log, Ian shows how  many  tubers  can  be  encouraged  by  this  method  to produce  as   many  as  four  extra new  tubers after the  initial growth has  been removed. ...
https://www.srgc.org.uk/logs/logdir/2016Mar161458126109BULB_LOG_1116.pdf

[Ian Y]

Here is part three of the Dactylorhiza method.

[Tristan_He]

Thanks Maggi and Ian, I will give that a go with my Dacs next autumn.

I feel like Dactylorhizas should have some sort of collective noun having watched that last video!

[Claire Cockcroft]

When I first started growing dachtylorhizas, I watched them increase slowly.  To hurry things up, I planted old flowering stalks in a pile of compost when I divided some tuber clumps.  As Ian predicted, those stalks produced many small tubers.  Over the years, nothing has worked as well as that pile of compost.  Since then, dachs have filled my garden with many, many hybrids so I no longer need extras.  Now I have to give them away when clumps need dividing.
...Claire

[Leena]

Those were very informative videos, thank you! I have only one Dactylorhiza, planted five years ago, and it has flowered every summer, but not increased at all. I should try this method next summer, and see if I could get more this way. If I have courage to do it:).

[Maggi Young]

Leena, so long as  you remove  the  new  tuber  carefully, there  is  no damage  to the  old  stem and  tuber  and  the  chances  of  success  are  good.

 It  is  unusual that your  plant  is  not  increasing at  all -  perhaps  too short  a  growing  season is  preventing  more than one  replacement  tuber   being  formed - in which case,  a careful attempt  to increase  using th is  method  could  be  just  what you need!

[Neil]

Leena it depends on how wet the soil that it is growing to wether it will produce extra tubers naturally. If it is too wet you will find that the current season tuber will start to rot away as the new tuber is being produced, so will probably only produce one tuber.

[GordonT]

Neil and Leena, I too have a Dact that refuses to multiply, however I suspect that its reluctance to set more than one tuber is due to excessively dry conditions after blooming. I'll have to try this method, and probably relocate the plant to an area with more consistent moisture.

[Leena]

Thank you Maggi for the encouragement! 
Growing season here is shorter, you are right. It starts to flower in the beginning of July, or maybe in the first week, and flowers almost all month. It is very pretty and I like it very much. I bought it from Dryad bulbs autumn 2014 so it is now six years old, and it is Dactylorhiza majalis x foliolosa.

Leena it depends on how wet the soil that it is growing to wether it will produce extra tubers naturally. If it is too wet you will find that the current season tuber will start to rot away as the new tuber is being produced, so will probably only produce one tuber.

Thanks Neil! Soil is moist where it grows but it is slightly raised so there is no water logging, but when I looked at Ian's video, his spot looks even more raised and dry than where mine grows.. I built that spot for my first Trillium (T.chloropetalum giganteum var Album) that same year 2014, with lots of humus. Trillium has grown well and multiplied slowly. Still, maybe that spot is too wet for Dactylorhiza!

Here are two pictures of it taken July 8 last summer. Now that I look at them, maybe it is too crowded and that is why it doesn't multiply.