A fenestration is an opening. In architecture, a door or window is considered a fenestration. When it comes to botany, or plants, a fenestration is a naturally forming hole or split in a leaf. Learn more about the types of plants with fenestrations and the best guess anyone has had to date about why these foliage holes exist.
Tropical Vibe
A fenestrated plant leaf will have holes or splits. Deep splits are known as lobes. Many types of Monstera and Philodendron have fenestrated leaves. Only mature plants produce holey or split leaves, regardless of the species. Young plants will exclusively have solid leaves, and splits or holes will develop at a certain point. New leaf growth on a mature, fully fenestrated plant will be solid, and the splits will come later.
What is the Purpose of Fenestrated Leaves?
There are a lot of ideas about why some plants have this unique leaf shape.
Prevent Water Catchment
Some claim that holes allow rain to pass easily through the leaves. The opening increases the odds of rain reaching the roots instead of being caught and held in the leaves.
Reduce Wind Damage
The holes may reduce the risk of gusty wind ripping a climbing vine or snapping a stalk. A solid leaf may catch the wind and receive damage, while the holes or splits create access for wind to blow through.
Cool Down
Another idea is that the increased edges help the plant cool down. Plants in particularly warm climates are less likely to overheat because the holes allow for increased airflow, regulating the temperature.
Catching Rays
An interesting theory that has gained support from people who study plants is that the fenestrations increase the plant’s ability to soak up sunlight. All the plants with fenestrations are understory plants, meaning they live underneath the tree canopy. Understory plants receive filtered sunlight, and there are a lot of plants fighting for this necessary resource. The splits or holes create a wide or broad leaf, which is more likely to receive sunlight. Some light may pass directly through the openings, but the openings are generally small enough to help more than hinder.
These theories make sense, but it’s hard to prove, and no one can definitively identify why some plants have fenestrations. Opponents of these various theories argue that fenestrations would be more common if they were such an excellent design. The notion is that more plants would have evolved to have fenestrations if they were such a superior design. Regardless, fenestrations exist for whatever unknown reason, and they give plants interesting character and a unique look.
Properly Identifying a Fenestration
Not all holes in foliage are fenestrations. Naturally occurring fenestrations will have smooth edges and a consistent green color throughout the entire leaf. Holes from pests or even curious pets will have jagged or inconsistent edges. The edges of the holes will turn yellow and eventually transition to brown.
Promote Fenestration in Plants
The unique shape and look of fenestrations make certain plants more sought after by collectors and plant enthusiasts. It’s completely understandable that you want your plant to form fenestrated leaves. Hedge you bet by purchasing a mature plant if you want the immediate gratification of a fully fenestrated plant. You can help a young plant along by providing plenty of sunlight and routine doses of fertilizer. Do not overdo it, because too much sunlight or plant food can have negative consequences. Plants that receive excellent care will reach maturity and start producing fenestrated leaves as soon as possible.