Wrinkled Leaf on Plant Problem
Here, we're trying to troubleshoot an anomaly on my Philodendron 'Moonlight'; a leaf that is twisted, curled and wrinkled during development. This post focuses particularly on Philodendron and its cultivars (Moonlight, Prince of Orange, Congo Rojo, Pink Princess, etc.) but the information present may be relevant to other plants.
A leaf that stays unfurled, seemingly forever, and is wrinkly in appearance. This occurs most commonly in the winter, but can happen all year round. When this happens, there are a couple options that you can do:
❶ Leave It Alone
It's been reported that if left alone, the leaf may never unfurl on its own and is eventually aborted by the plant; dying off. Sometimes they will eventually unfurl, but takes a spectacularly long time.
❷ Manually UnFurl It
If you help it unfurl, the leaf will expand but never normalize: it is wrinkled forever (which is my personal experience). This does not hurt the plant and often the plant continues growing as normal.
The Causes and Solutions
Wrinkled leaves are usually an indicator of unstable growing conditions at a point in the leaf's development where growth has started, stopped, started, and so on. This can be caused by:
❶ Leaf growth interrupted by dormancy during winter
Solution: this may be unavoidable, but you can discourage new growth by stopping fertilizing early.
❷ Irregular watering with long periods of drying out inbetween
Solution: philodendron can tolerate drying out inbetween but not prolonged. Keep a better eye on your watering schedule and ensure even watering throughout the pot.
❸ Temperature fluctuations
Solution: keep away from drafty windows. This is particularly important during winter where a cold window and heated interior provide inconsistent temperatures by a sill.
❹ Inadequate humidity
Solution: a humidifier or lastly misting directly on the leaves may help.
Solution: treat with an insecticidal soap or an alternative pest control method.
❻ Cultivar (?)
@cokeandwet and @sweetnepenthes first mentioned that perhaps this is just a problem with the cultivar. Cultivars are plant varieties produced by selective breeding and perhaps the 'Moonlight' and similar became particularly sensitive to change during leaf developement.
If the following new leaves are perfectly normal, you just had a hiccup in your growing conditions and the plant is perfectly healthy. Overall, I found this problem to not be high on the worry list.