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The Monstera genus (Araceae or Aroid family) are particularly intriguing plants demonstrating heteroblastic (having different young and adult forms) leaf morphology.
Monstera plant vines produce fenestrations, holes within the leaf, and deep lobes from both sides close to the leaf’s midrib. Monstera vines are identifiable by their leaf splits, known as fenestrations, formed by genetically programmed cell death.
- More About Monstera
- Why & When Do Monstera Leaves Split?
- When Do Monstera Leaves Split?
- Boosting Monstera Leaf Splitting
- Monstera Leaf Splitting Summary
More About Monstera
Monstera deliciosa, also known as the split-leaf philodendron, Swiss cheese plant, or window leaf, is a tropical plant native to the rainforests of Central America, ranging from southern Mexico to Panama.
It is frequently grown as a foliage houseplant. It has glossy, leathery leaves with spherical or heart-shaped shapes that age to include deep clefts and oblong holes (fenestration). The leaves on foot-long leafstalks can be up to 18 inches wide.
The leaves of the “Variegata” and “Albovariegata” cultivars are variegated and typically somewhat smaller than those of the species.
This plant is an epiphytic vine that climbs or trails through the rainforest canopy, also called an evergreen liana. It rarely branches and can reach heights of up to 70 feet using hefty, rough, cylindrical stems that are two and a half to three inches thick and are covered in leaf scars.
Monstera Clinging Aerial Roots
As the vine climbs, it develops numerous, long aerial roots that resemble tentacles and cling to adjacent branches and tree trunks.
The thick stem produces robust roots that grow downward and take root if they come in contact with soil. The fenestrated leaves catch rain and channel the water down these aerial roots.
Heteroblastic Leaf Morphology
The youngest plants have a completely different appearance from adult plant leaves. Young Monsteras are skototropic, i.e., unlike most plants that grow toward the light, they grow towards darkness.
Monstera plants grow towards the darkest space on the horizon as evolution has taught them that the dark shape represents a tree upon which they climb to greater heights.
Young plants are known as “shingle plants,” like the Monstera Dubia, with smaller individual leaves without lobes or holes. The leaves develop closely, overlapping one another up the tree trunk, and they start splitting as they become older and are exposed to more light.
Monstera Plant Flowers and Fruits
The flowers are a sort of Jack-in-the-pulpit eight to twelve inches long, creamy–white, and hardly ever seen on houseplants. The boat-shaped spathe is positioned around the fleshy upright spike (spadix) with tiny flowers.
The fruit takes over a year to fully develop, growing to a height of nine inches and resembling a green cob of corn with hexagonal kernels. The edible fruits, also known as cerimans or monsteras, are rich in potassium and Vitamin C and are said to taste like a blend of banana, pineapple, and mango.
Monstera as a Houseplant
In the summer, the Monstera plant needs bright indirect light and can direct the winter sun. The Monstera plant grows well under fluorescent lighting, but insufficient light prevents the development of leaf fenestration.
Once acclimated, it can tolerate a range of environments but prefers a warm ambient temperature and medium to high humidity. However, below 50°F (10°C), plants will become stunted, and frost will kill them.
Grow Monsteras in a well-draining, organic-rich soil that offers enough root space to encourage the development of larger leaves. They tend to increase, so support is necessary to prevent the stems from breaking.
Give the aerial roots moss-covered support or wrap sphagnum moss around a wooden slat, watering it occasionally for moisture and nutrient access. Water the Monstera plant thoroughly and let the soil dry out between applications.
Plants cultivated in a dry environment will grow more slowly. Winter means less water. Regularly fertilize from spring to fall. If the humidity is too low, the leaf edges will become brown. Periodically wipe the leaves to remove dust, and ensure you watch for signs of root rot.
This plant hasn’t many indoor pests, although it could get aphid, mealybug, scale, or spider mite infestations.
Plants growing in containers need regular repotting to make room for growth and ensure root health.
Monstera and Pets
Aside from the ripe fruits (which seldom develop indoors), all portions of the plant contain oxalic acid toxic to humans and pets. Keep the Monstera plant out of reach of teething pups, catnip hunter cats, and curious future culinary chef kids.
Why & When Do Monstera Leaves Split?
Research by the University of South Florida has eliminated one of the most commonly cited reasons why the Monstera’s split leaves evolved to manage hurricane winds. According to the research, it is more probable that the fenestration ensures a better water supply down the trunk, directly to the roots.
The enormous variance in leaf morphology among various plant species is a crucial part of tropical forests’ biodiversity. Adaptations to the unique environmental circumstances of a particular ecosystem or habitat frequently lead to changes in leaf shape and the reason monster leaves split.
Monstera leaves split as a product of age, light, relative humidity, and ambient temperatures, so let’s see how we may boost the likelihood of fenestration.
Split leaves help the Monstera plant to survive when it is high in the canopy. Split leaves allow water and light to reach the lower parts of the plant.
When Do Monstera Leaves Split?
Managing the Tension Between the Need for Light and the Need for Water
Encourage Monstera growth with adequate light and pruning. Younger plants have whole leaves without fenestration, pinnations, or lobed margins. This is because your baby Monstera is more interested in generating food under a canopy of plants that afford only stochastic (randomly variable) access to light.
Photosynthesis is a Top Priority
Because light is more limited than water to your juvenile Monstera leaves, photosynthesis is a top priority. The monstera leaves need to grow in size to maximize photosynthesis, gathering as much light as possible.
Young Monstera and Light
Younger monstera or baby monstera have dark green leaves that are lower in the canopy and must attract much more light. As they grow, these heart-shaped leaves split as they climb the canopy.
Evolution has also taught this plant that light availability improves the higher up one goes in the forest canopy. Enter skototropism. Skototropism is a variation of phototropism, a plant’s response to light stimulus.
What is Negative Phototropism?
Negative phototropism is a plant’s negative response to light, i.e., growing away from the light. Skototropism takes it a step further; not only is your little Monstera growing away from light, but it is also actively seeking the darkest shape on the horizon.
Your young Monstera does this because it has discovered that the dark shape on the horizon is most likely a host tree.
As young Monstera grows up the tree and the light levels improve, water becomes more important than light, so the leaves morph, developing fenestrations and lobes to channel this liquid resource down its stem directly to its roots.
Boosting Monstera Leaf Splitting
You can help your Monstera leaf fenestrations, lobbying, and even variegation processes by providing it with an optimal environment. This would include the following:
- Medium-light in winter and indirect bright light in summer. Your Monstera plant will suffer sunburn if put in direct sunlight.
- A humidity level of around 60%. The lower the humidity level, the higher the levels of transpiration (water loss), and the more water the plant will need.
- An adequate support structure. Your Monstera can grow to extraordinary lengths (+70 feet), and giving it a support structure signals the plant that it is starting to mature. It can now stop prioritizing photosynthesis and start monstera leaves to split.
- A soil that drains well yet can retain enough moisture to keep the plant hydrated, especially in warmer weather and at increased light levels.
Monstera Leaf Splitting Summary
As we’ve seen, Monstera plants are ingenious, managing their leaf morphology to respond to prioritized needs. As light levels increase, so does fenestration, and monstera leaves splitting. We also looked at optimizing plant health for the way to split monstera leaves. I trust we’ve been able to provide you with answers to when Monstera leaves split.
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