My plant looks amazing with new growth, however this just started happening with the leaf? Do you have any idea what is causing this? Also, I have a bird of paradise that was doing well and now seems to have stopped growing. There is a new leaf that has been there for approximately two months yet does not grow or open, also the one leaf is curling in and turning brown. Any suggestions? Thank you so much.
‘Black Magic’ is one of the loveliest of the many varieties of Colocasia, with its spectacular deep burgundy-black foliage. The most frequent cause of yellowing leaves on indoor plants is overwatering. It isn’t possible to tell with certainty from your photograph, but it looks as though your plant’s pot is not resting in an outer saucer, and I wonder if there are drainage holes in the bottom? Good drainage for any houseplant is crucial for good plant health – excess moisture retained in the soil can cause root rot, which will show itself in yellowing of leaves, and if you check the roots themselves, root rot is indicated by spongy, slimy root structures.
If your pot does not have holes for drainage, we recommend repotting your Colocasia in a slightly larger pot with drainage holes, using a good commercial indoor potting medium (never use outdoor garden soil), and sitting your new pot inside a glass or plastic saucer so that any excess water can run through. Don’t let the pot stand in water – empty any that remains in the saucer after watering.
Too little light can also cause yellowing of leaves. Colocasia does best in bright, indirect sun and appreciates a higher degree of humidity, so a regular misting of its leaves, or having a humidifier close by, should be helpful.
Many tropical plants such as Colocasia have a natural period of dormancy through the winter. During winter you can cut back on watering, allowing the top layer of the soil to become quite dry between waterings. In the early spring, you can begin to increase your watering schedule. Also in spring you should consider a fertilizing regimen every two weeks, using a weak fertilizer formulated for houseplants with a balanced ratio of nutrients which will be indicated on the container (e.g., 1-1-1).
Like Colocasia, Strelitzia, or Bird of Paradise, is a tropical plant that will typically experience a period of dormancy or slower growth indoors in the winter. In Strelitzia leaf browning can be a symptom of overwatering, so be aware of allowing the soil to dry out between waterings. As noted above, good drainage is important, as is bright indirect light (this plant can also tolerate some direct sunlight). Leaf curling and browning can also be a symptom of dryness: like other tropical plants whose natural habitat is humid, our own households are often not high enough in humidity during the winter. Misting the leaves regularly, or using a humidifier in the room, will help to combat this. In spring Strelitzia will benefit from a weekly regime of fertilization with a product formulated for houseplants. It will also happily spend the summer out of doors.
Best of luck with these two spectacular specimens!