Evergreen, Deciduous, Semi-deciduous Orchids

[TheOrchidHut]

When it comes to these botanical terms for orchids, it seems that evergreen and deciduous are clear. However, how would a semi-deciduous orchid loose its leaves? Some schools of thought seem to promote leaf loss specifically every two years in order to meet the semi-deciduous definition. Other interpretations seem to support any sympodial orchid that looses older leaves on back bulbs/canes as semi-deciduous as well, regardless of the time it takes to do so.

Any input is appreciated - the debate seems to be never-ending.

Thanks!
-D.

[Roberta]

Originally Posted by TheOrchidHut

When it comes to these botanical terms for orchids, it seems that evergreen and deciduous are clear. However, how would a semi-deciduous orchid loose its leaves? Some schools of thought seem to promote leaf loss specifically every two years in order to meet the semi-deciduous definition. Other interpretations seem to support any sympodial orchid that looses older leaves on back bulbs/canes as semi-deciduous as well, regardless of the time it takes to do so.

Any input is appreciated - the debate seems to be never-ending.

Thanks!
-D.

First, welcome!

I'm not sure there is a solid definition of "semi-deciduous" ... even "deciduous" has some "shades of gray". Cultural conditions play into this too. There are quite a few that tend to lose leaves in response to dryness or cold or other environmental stress, but may keep their leaves under more mild conditions. (In nature , not just in cultivation) I think that these are more functional descriptions. The main takeaway here is, if you have an orchid that is considered "deciduous" or even "semi-deciduous", and it loses leaves, it doesn't mean it's dying. For instance, when I have a Dendrobium that looks sort of dead, even somewhat shriveled, I keep it around for about a year to see if it revives. If it stays "dead" it probably is. But don't rush to dump a plant that looks bare, especially in cool weather. As you get used to obeserving these plants over time, you do learn which canes or growths have already totally given their vitality to the plant, which are old but still viable, and which are bare but are very alive (and likely to bloom) Rather than getting too involved with the definitions, use the descriptions as an indication of what to look for, and observe the plants over time.

[mr.wolfe]

It's rather like those "evergreen in Hawaii" tags you see in gardening books. Many orchids that are deciduous for people in colder climates won't die back in temperate zones. On the other hand, there are ones like the Corybases, which grow from a small tuber, and die back after blooming without fail.

I guess it depends on your personal definition, like Roberta said. No standard that I know of.

[Roberta]

Also a note, no leaf lasts forever. So losing an old one even under perfect conditions is likely just force of nature. So it's not "if" , it's "when". And the overall health of the plant, as well as knowledge of its normal seasonal habits, will help to tell you whether you have a problem or are just watching nature at work.

[Ray]

Yes, culture can also play a role. Those “deciduous” Chinese phalaenopsis held their leaves well when I kept up the watering.

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