Angraecum didieri leaves yellowing and falling (6th in 2 months) - Orchid Board

mvmgems · #1 12-18-2021, 01:04 PM

My Angraceum didieri was doing ok over the summer and fall, growing leaves (slow but I guess that’s typical?), but lost some roots to the lower humidity at home. Right now, baby new leaves are starting to come in and some aerial nubbins have started, but it’s LOSING leaves at a much faster pace, usually the bottom or second from bottom in a fan. This is the sixth leaf it’s dropping in the past two months, and the largest leaf of all.

What am I doing wrong? Lives at a south windowsill screened by other plants, getting 2-3h of morning sun, temps 65-80F, humidity 35-65%, in original potting mix of what looks like small/medium bark chips, watering 1-2x a week with soak and misting the aerial roots most days, and feeding every 2-3 weeks with 33ppm N MSU.

Roberta · #2 12-18-2021, 01:31 PM

Only thing I can think of is watering too infrequently. It's in an very open medium, and should probably be treated like a mounted plant - watered every day if at all warm especially if humidity is low, every other day at a minimum. This species grows very well mounted, so the potting situation looks very good . So try increasing the watering frequency,

Shadeflower · #3 12-18-2021, 02:21 PM

can't help, same happened to my didierii. In the end the stem just rotted away completely.

Ninja would tell me it was the shop where it came from and the year I bought it - who knows... I honestly don't thik I did anything wrong with mine but it also eventually packed it in after 6 months.

edit: you might want to have a look what is going on in the substrate in the pot to check it isn't too degraded in the middle

Roberta · #4 12-18-2021, 02:40 PM

@mvgems, also skip the soak... these do like to dry between waterings So more often watering, no soak... When it gets too dry, I suspect the leaf drop is due to its reaction to "drought" - water is lost through leaves, so if it doesn't have enough water it drops them as a defense mechanism. Madagascar, where these come from, is a pretty wet place even in the dry season. The new roots and new growth are a good sign, It will do aerial roots, its natural inclination. Once it has a good supply of those, what is happening in the pot will be irrelevant once it has water at an adequate frequency. Temperature is fine - I grow mine outside, temps get close to freezing, But it does get daily watering,

mvmgems · #5 12-18-2021, 05:09 PM

I was hoping not to disturb the roots until it was well established here, but at this point it’s probably the lesser evil.

Another factor I thought of is that I misted it when I got home last night, and I think some of the other leaf drops may also have happened with nighttime watering as well. Will have to keep an eye on that too.

Roberta · #6 12-18-2021, 05:26 PM

Quote:

Originally Posted by mvmgems

I was hoping not to disturb the roots until it was well established here, but at this point it’s probably the lesser evil.

Another factor I thought of is that I misted it when I got home last night, and I think some of the other leaf drops may also have happened with nighttime watering as well. Will have to keep an eye on that too.

Generally, best in cool weather to water early in the day, Then it has a chance to dry out before nightfall.

As far as root disturbance goes, most Angraecums seem to resent it, If you unpot and just shake of old medium, that should be sufficient. In short, try not to disturb roots. Just add some fresh medium (loosely). But this species is a dominant epiphyte... so the medium should not do much more than contribute a bit of humidity. You need frequent watering and then drying.

Shadeflower · #7 12-19-2021, 06:27 AM

the last thing I want to do is recommend to grow it mounted but at the same time you should treat it a little like a mini vanda, ie lots of air flow around the roots.

Also if I were to ever get one again I would never spray the stem directly again. Spray the outsize edge of the pot to moisten the roots but avoid the stem area...

mvmgems · #8 12-21-2021, 09:28 PM

Repotted into a slotted pot and airy mix of orchiata bark with a touch of moss. I can’t do mounts as I’m often away from home for several days, and it gets hot and dry inside the house. The roots weren’t in bad condition, I took the advice here and just shook off what easily came off but didn’t disturb the rest.

Unfortunately the repot was made pressing by one of the fans getting crown rot. All the leaves including the baby were soggy brown. I cut as low as I could without sacrificing the neighboring fan, but the cut still hit soggy tissue. Packed the cut full of cinnamon and hope for the best?

Shadeflower · #9 12-21-2021, 09:38 PM

you are lucky it was just one of the smallest keiki's that rotted by the looks of it. The main plant looks in great shape tbh. All sounds good or not as bad as it would seem I think but I know the feeling. Like I've mentioned recently a couple of my neo's have been causing me similar problems too lately.

mvmgems · #10 12-23-2021, 12:47 AM

Well this might become a bit of a saga! Adjacent small fan started yellowing today, so I dug it back out of the pot dry and found one moldy and another rotten root near the two. Snipped them off with the fan, and cinnamoned the wound. On the opposite side of the plant there was a healthy looking keiki with a sheath at the base that was soggy and brown. I used tweezers to tease it off, but there were healthy roots at the base so I didn’t cinnamon.

Put it back in the pot, where luckily the roots are wide enough that it can wedge without too much wiggling, then loosely packed in small-medium orchiata bark with a couple strands of moss, lots of air gaps. Didn’t wet it today and will let it dry out a few more days before watering.

Edit to add: looking up the symptoms, this matches Pythium/Phytophora. I care enough about this orchid that I’m willing to try one of the systemica recommended by St Augustine (Banrot, Subdue, Alliette), but where can one find quantities that aren’t like a quart and well over $100?