Paph delenati will not grow or bloom

[MJG]

I've had this paph for 6 years now. It is labelled Paph delenati 'SM' x delenati var - vinicolor (dualcel). It does not grow or flower. I'm wondering why.

I grow it and my other paphs in my sunroom (just a room in my house, cental air/heat like a house) with eastern exposure in central NY. I use supplemental lights and humidity in the fall-winter-spring. I fertilize with Jack's 30-10-10 once a month in winter and every other week or weekly/weakly spring through fall. All of my other paphs grow and flower in these conditions.

This is a small plant. It is in a 3 inch pot. Every year it will grow a new little leaf or two but that's all. Suggestions?

[SouthPark]

That's probably one of the things with this particular kind of orchid. It's along the lines of a vietnamense type, right?

If starting from a small plant, or juvenile baby plant, then it can take a long time to get to a flowering stage - for this particular type maybe.

The nice thing about this plant of yours is that --- it appears to be retaining its leaves. Your initial comment says it will not grow ...... but that cancels with your subsequent remark about it growing a leaf or two each year.

The slippertalk (forum) guys and girls could possibly help out too with this particular kind ..... delenatii. They can definitely give some opinions too, aside from anyone growing delanatii within orchidboard forums.

I don't grow delenatii, but have two juvenile vietnamense ..... relatively slow growers heheheh.

I wouldn't be surprised if your plant does actually flower in the near future!

Maybe you could even 'up' the lighting level a tiny bit - just to try something extra.

[MJG]

Interesting thought sparked by your comment about upping the light... I have always kept this with my other paphs and adjusted lighting based on how most of them react. Maybe I should treat this one differently and group it with some higher-light loving orchids.

To clarify my comments about not growing. It does grow one or sometimes two new leaves per year, but it also sheds one or two. So it remains the same size. It is the same size today as it was when I bought it 6 years ago.

I watched an online video about delenatii on a grower's website. Theirs have much bigger leaves than mine. After 6 years mine isn't a juvenile. I wonder if mine could be a miniature cross if such a thing exists, or if its growth is just stunted for some reason.

[Paphluvr]

My first impression of your plant is that the mix looks rather coarse for a Paph. mix and is very dry. I would normally not use a pot with that much aeration for a Paph. No roots are visible on the wall of the pot. Generally, slow growth is the result of a poor root system. Do you have any idea of the health of the root system (i.e., has it been repotted recently)?

[MJG]

I did repot this about a month ago. The new potting medium is a mini bark mix. The orchid has only 2 roots, both very thick and hardy looking and about 2.5" long. They're both very stiff and go straight down which is why they're not visible. I used some rooting hormone on it when I repotted.

It does look dry, doesn't it? I watered it thoroughly 2 days ago.

Before I repotted it was in a 4" ceramic orchid pot in a courser bark mix. It stayed damp for much longer. So, that's been its growing condition until recently. I repotted it thinking that I might be leaving the roots too damp between watering. It also needed a smaller pot.

What potting medium would you suggest? Also, what do you think about the root situation?

[Paphluvr]

Did you wet the new mix before you repotted? With bark I generally pour some boiling water over it, give the bag a good shake, seal it and let it sit overnight before using it. It should be moist when you use it.

The mix I use for my Paphs is quite different than yours. I use small CHC mixed with coarse perlite and a bit of sharp silica sand. This is just something that works for me. Plenty of growers grow in fir bark. I'm sure you'll get other replies as to what other growers use. I am glad to see you using a clear pot, it helps to guage when watering is necessary.

[BeautifulDay]

Hello,
I purchased a paph Delenatii nearly five years ago it didn’t grow very much and sadly this summer in some hot Australian summer temperatures and high humidity rotted and slowly died.
Because I LOVE this orchid I brought 3 other varieties of Delenatii from different growers not long after my first one. These three flower every year (well three years in a row ) and are great even though they were smaller orchids then my first one when I got them.
My opinion is some varieties of this orchid are more difficult to bloom than others, because I treated all mine the same and one was difficult and the others are reliable bloomers.

[estación seca]

My observation over a few years here on Orchid Board has been that people who grow Cattleyas and Phalaenopsis before they grow Paphiopedilum generally underwater their Paphs. I sure did. When I stepped up the watering, and fixed the pH, Wow!

Catts and Phals are not bothered much by the wrong pH, but Paphs can be.

[SouthPark]

Originally Posted by BeautifulDay

Because I LOVE this orchid I brought 3 other varieties of Delenatii from different growers not long after my first one.

BD ----- did you make any adjustments after that first one didn't make it due to high temperatures etc?

In North QLD, I haven't got a delenatii, but have two small vietnamense (in separate small pots). Both doing nicely for a couple of years or so now. There was one time when one of them was getting hit by something - starting out as leaf rot, which slowly spread across two leaves ...... slowly, not quick spread.

I tried phosacid, and thiomyl and mancozeb - giving each a chance to do something ----- none of them improved the situation. Finally, a spray of yates liquid copper stopped whatever it was in its tracks. Completely stopped it. Pretty sure whatever it was - would have wiped out the whole plant.

My growing area has pretty good air-movement in general. But anyway - both vietnamense are doing nicely - each growing in about 5 mm average diameter scoria. I water them every morning (got time on my hands heheh) ------- I just spray water down into the media toward the sides of the pot.

Originally Posted by MJG

I watched an online video about delenatii on a grower's website. Theirs have much bigger leaves than mine. After 6 years mine isn't a juvenile. I wonder if mine could be a miniature cross if such a thing exists, or if its growth is just stunted for some reason.

Hard to say MJG. I like that comment from ES about pH ...... could probably check pH.

Anyway - I think that as long as the orchid isn't taking a bad turn in health, then that's a good thing. If it maintains its health, but grows very slowly, then that's definitely better than a backwards health thing.

[BeautifulDay]

Hi South Park ,
I have got better with Paphs as the years have gone on so maybe that’s the reason my first Delenatii struggled , but I only had the first one six months longer than the next three but as it was my first ever paph mistakes were definitely made!
I swear by advise given to me by Nicky a breeder and grower from Nickys orchids in SA he said most people who say they don’t have any luck with Paphs either keep them in too bright light or overpot them. You should choose the smallest possible pot with their roots just fitting into their pot.
He also said he sprays as a preventative to rot Mencozeb and liquid copper ( mixed together)a few times a year. He has a huge paph nursery and I have a lot of his plants from orchid shows.
He only told me the spraying advise six months ago so hopefully that works next summer.

I pot my paphs with perlite, 6-9 mm orchiata bark and charcoal but I put a little sphagnum moss on top and when that is starting to dry slightly I water.
I change the sphagnum on the top every six months as it breaks down more quickly than the rest of the media but it doesn’t disturb the rest of the pot.
So I water my paphs individually as some dry more quickly than others. Like the ones with big root systems. Some need watering once a week some two weeks. I check the moss every day. I don’t have much spare time like you but as my collection is small ( 30) I can baby them!
I have three orchids that this year have put out two spikes each so I’m very proud and excited about that!
I now have the normal Delenatii and also have colour variety “Album“ and “Vinicolour”. They are all in bud again now, mine seem to bloom at the same time each year not sure if it is a coincidence, they must be seasonal?