Giant Bird Of Paradise leaf problems

fluppyboyg3nONhu5

Hi
I recently bought a Strelitzia Nicolai, giant bird of paradise from my local nursery. I made the mistake quite quickly of spraying the bottom leaves with aeroguard to stop my puppy from chewing on them, which led to chemical burn. I cut the leaves off and repotted it. All the roots were nice, white and healthy and showing no sign of ill-health. About a month, after that, I’ve noticed that the remaining leaves have developed little white spots, little black spots and little brown spots that look like a shallow hole in the leaf. They’ve now started to develop yellowing. I water well, once every 7 to 10 days, and the plant sits in a north facing window (I live in Australia and it’s Summer now). I’ve had two different horticulturists give me different information. One says it’s a fungus issue and I need a fungicide and the other says it’s a watering issue (too much or too little) and small circular burns where I’ve misted the plant and the sun has magnified the droplets.

As the leaves are getting worse, I can’t see it being a magnifying issue, but I’m asking for some help with this as I don’t want to lose the plant.

Any suggestions would be greatly appreciated 

Thank you 😊 

AnniD

*bump* 

thevictorian

Hi,

I don't know what is in aeroguard but unless you specifically sprayed those areas of leaf more than the tips, I don't think it's chemical burn. Chemicals can definitely cause a similar appearance but I would have thought you'd see evidence of it all over.

I also don't think it's over watered and I'd rule that one off the list just from the pictures but you can check the soil is moist and not soggy and only water when the top of the soil is dry down to an inch or two (just stick your finger in the soil and if it comes out clean you can water again). Over watering usually presents with yellowing leaves as the roots begin to rot and the plant can't take in the nutrients it needs. 
If it was underwatering then you would likely see some dry brown leaf tips and edges, which I can't tell from the picture.

I'm not sure what your climate is like but higher humidity (as well as to much water) can cause fungal leaf spots. We wouldn't need to mist them here and they can normally cope with our sun, although it's still not the best idea to have direct sun on them in the hottest part of the day in summer. I would have thought if it was caused by humidity it would present in more places, the same if it was caused by magnification.

It's really hard to diagnose which is why the ideas people have put forward are all plausible. The easiest thing is to rule things out. I can't see any pests like mealy bugs or scale but I'd check for them. I'd then check the soil to see if it is to wet or dry. These plants like good drainage so perhaps raise the inner pots on a thin layer of shingle (it will also aid humidity). Then I'd move on to fungus as I think there are a couple quite common with bird of paradise.    

Fairygirl

I'd have thought you'd have it outside at this time of year if you're in Australia.

The ordinary Strelitzias can certainly go outdoors in the UK in summer. Perhaps it would benefit from a bit of outdoor air. 
It looks quite pot bound in your first pic. It might benefit from some fresh soil and a bit more room 

Paul B3

I can only envy (in a nice way) , the opportunity to grow a plant like yours outside in dappled shade during an Australian summer .

Your plant would be much healthier and stronger in the open air ; agree totally with Fairygirl .

If you can , lose the pot and plant in open ground ; you'll probably be amazed at the rate of growth .........good luck !

Obelixx

I'd have thought it would be better off outside in the ground in most of Oz except maybe Tasmania.   I have a large one here that is in a pot but goes outside on the south facing front door steps, so full sun, once night time temps get to 10C in spring.  

Normally it would spend winter in the polytunnel but this year it's decided to flower again so is in the living room, south facing window, and is being watered when the top part of the compost feels dry.   It'll get a monthly shower to kep the leaves dust free and humid.

Try putting yours outside in a bigger pot with fresh, loam based compost, and keep it watered as needed.  It should recover unless there is a pest or disease we can't see in the photo.