Watering When: cauline type Pterostylis

A common question asked is when to water terrestrials. The short answer is to keep them dry over summer but there are variations such as was previously posted about the watering regime for Chiloglottis. In the March 2017 NOSSA Journal, Les Nesbitt’s article highlights another watering variation.

Blue Tags

Les Nesbitt

Jane Higgs’ lovely pot of the red form of Pterostylis coccina in flower had a blue tag. Jane explained that a blue tag meant that watering had to commence in January for that pot and not at the end of February as is normal for most terrestrials. Start watering later and there will be no flowers. Her pots are under a solid roof. She explained that in the ANOS Vic cultural booklet (Cultivation of Australian Native Orchids) there is a list of cauline type greenhoods which she tags with blue, and includes Pterostylis decurva, aestiva, laxa, coccina, revoluta, reflexa, truncata, robusta, alata, and fischii. To this list can be added abrupta and also the rosette types ophioglossa and baptistii which shoot early.

I have trouble growing and flowering this group of Autumn flowering greenhoods. I went home and dragged out my ANOS Vic booklet and brushed up on the notes. I found several old blue labels in the shed and cut them into strips. I now have blue labels in my pots and the pots are grouped together in the shadehouse where they get afternoon shade. They were given a thorough watering but it will be too late to expect flowers this year. I find large tubers of this group rot easily in Spring and the plants go dormant earlier than other greenhoods. I will try to remember to move the pots under cover in September to let them dry off.

Diplodium in cultivation
Diplodium robustum – one of the cauline greenhoods

Having a visual reminder would certainly make it easier to know when and which pots to water. Obviously other coloured tags can be used instead of blue, so long as they stand out from the label.

 

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