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Sansevieria Masoniana (Whale’s Fin Plant) – The Ultimate Care Guide

Sansevieria masoniana, commonly known as Mason’s Congo or Whale’s fin is a semi-succulent, stemless and evergreen plant. It has characteristic wide leaves that look like paddles or beaver’s tails. This unique shaped plant also comes in variegated forms. Easy to cultivate and grow, it is excellent as a large houseplant, for indoors as well as outdoors. Like most snake plants, it is sturdy and difficult to kill. Sansevieria masoniana needs almost the same care as the standard snake plant (Sansevieria trifasciata). Let’s see in detail how to care for this beautiful species.

Benefits And Uses

  • Mason’s Congo plant looks equally gorgeous as a single accent plant in your house or in mass in planters or beds. Even with just one leaf, it makes a great choice architectural statement.
  • Like most Sansevierias, it is believed to act as a good air purifier by removing toxins (such as formaldehyde, xylene and toluene) from the air. Big surface area of the leaves makes it even more efficient in absorbing the harmful pollutants.
  • Because of a rare CAM photosynthesis, Whale’s fin plant converts carbon dioxide to oxygen during night also. This makes it a perfect pick for bedrooms.
  • Sansevieria Masoniana thrives on minimal care and lives for many years, making it the perfect houseplant for beginners.

Plant Size And Growth

Sansevieria Masoniana is a big plant that generally grows up to 3-4 feet tall. But given the optimal growing conditions, it can reach a height of 5 feet. The leaves are up to 10 inches wide in the middle, dark green colored with smudged light-green spots. They are upright, rough, leathery and fibrous. Sometimes the leaves have slightly wavy, irregular borders. The plant also has a unique purple banded basal sheath below the soil level.

Sansevierias are slow to medium growth plants. And it will take years (or decades) for this plant to reach its ultimate height. Flowers can occur anytime of year, but mostly from summer to winter. This happens at most once a year.


A loose, well-drained potting mix suits best for Sansevieria Masoniana. It can easily grow in soilless medium also. One of the most common reasons why a snake plant dies is root rot due to wet and soggy soil. So, use a light and fast draining soil to keep your Sansevieria healthy.

Recommended soil mix for the Sansevierias consists of additives like pumice, perlite, coir or gravel to increase the drainage capacity. Read this post to know more about the best soil ingredients for making your own soil mix at home. Some ready-to-use potting mixes made for cacti and succulents also work great for the Whale’s fin plant.


Choosing a correct pot is an essential part to care for Sansevieria Masoniana. The most important thing to look for in a pot is the drainage. If your pot doesn’t have drainage holes, you can make them using a drill. If that’s not possible, consider a double potting method. Use a smaller pot with holes inside a big ornamental pot. This will make your plant look good while ensuring proper drainage.

A pot should have a suitable size, not too big and not too small. Place your pot on a stand or saucer. You can also keep the pot on pebbles, so that the roots stay above the drained water.

Masons Congo Sansevieria Sansevieria masoniana
Image source: Mokkie / CC BY-SA (

Watering Schedule

Mason’s Congo is a very drought tolerant plant. To avoid overwatering and root rot, water the plant sparingly. Take care not to water the center of the rosette because the leaves rot easily if kept wet. Misting the plant is not necessary. But if you decide to do so, mist it during the daytime so that the leaves can dry quickly.

  • Allow at least the top inch (2.5 cm) of soil to go completely dry before watering.
  • Water it slowly and deeply enough for the water to come out of the drainage hole.
  • Make sure to discard the drained water. Never allow water to make the soil soggy as that will lead to root rot.
  • After watering the plant, make sure to keep it in a bright area. And don’t water unless the soil is dry again.

You can water it once a week in summers if kept in moderate to bright light. During colder months, reduce the watering to once a month or less frequently than that. In winter, water just enough to prevent the soil from completely drying out.

Light Exposure

Sansevieria Masoniana can survive in just about any light. It tolerates bright light to full sun, and also low light. Although it won’t die in very low light levels, bright light brings out the colors in the leaves and makes it flower. For ideal growth, place your snake plant in moderately bright or filtered light.

Good location would be a north or south facing window where it doesn’t receive direct sunlight. You can also place the plant in front of a bright and sunny window behind sheer curtains. Keep them away from direct sun, especially in the afternoons.


Average room temperature, usually in the range of 60-75° F (16-24° C) is perfect for Sansevieria Masoniana. It will tolerate fluctuating temperatures, but not extreme cold. Theoretically it is safe at 30°F (-1° C) if the roots are not frozen. But don’t let the plant experience temperatures below 50° F (10° C), as it can cause cold damage to the foliage. Winter frosts will kill the above-ground leaves, but the roots can be saved if kept dry. It is prone to suddenly rot, especially if exposed to combination of cold and excessive water.

It can easily tolerate high temperatures, but don’t place your snake plant right next to a radiator or heater. It can dry out the soil quickly. Keep your outdoor plants in partial or full shade. Take a look at this post to know perfect light, humidity and temperature conditions for snake plants.

Pests And Diseases

In general, Sansevieria plants are quite immune to pests. Due to their thick, succulent leaves, they’re not easily bothered by bugs. However, sap-sucking insects like spider mites and mealybugs can attack the plant on rare occasions. Your snake plant won’t necessarily die even after the pest infestation. To control these two bugs, wipe off the affected area with alcohol dipped cotton balls. You can also use diluted liquid soap to remove the bugs from plant leaves. Repeat weekly until the insects are completely gone.

The most common disease that affects the Sansevieria Masoniana is root rot. This happens when the soil remains soggy for too long. It makes plant roots dark, mushy and turns the leaves yellow. Presence of moisture on the leaves can also cause fungal diseases like red leaf spot.

Early detection is good to prevent major infestation. So, inspect your plant occasionally for the signs of infection. Read more for symptoms and treatment of different pest infections in snake plants.


Sansevieria Masoniana doesn’t need a lot of fertilizer. Feeding this plant 2-3 times a year is good enough. Natural fertilizers like cow dung, worm compost should also be used sparingly. Throw in a handful of it in the potting soil mix. The best time to feed your plant is just before and during the growth season, which starts from the spring.

If you use a slow release fertilizer, add it in the soil once a year in summer. Liquid fertilizers are very convenient and less risky. Use a half strength diluted liquid fertilizer with balance N-P-K ratio. It can be applied up to once a month during the spring-summer seasons. Check this fertilization guide for more details.

Never fertilize your snake plant in the winter. Sansevieria are in the state of dormancy during this time, and they don’t need much water or nutrients. Supplementing your plant with a fertilizer adds to the plant stress. Also, don’t fertilize young plants, especially after propagation. Wait for at least a month after the plant is repotted in soil.

Grooming And Maintenance

Generally speaking, a whale’s fin plant doesn’t require frequent maintenance. It grows slowly and doesn’t spread wildly. However, because of the wide leaf surface, it may acquire some dust on the foliage. Gently clean the leaves a couple of times a month. You can do this every time you water the plant. Other than that, you can keep the plant in your home for years, and it’ll look just fine.

If you wish to retain the size of the plant, it can be trimmed down every 2-3 years. For this, remove the old, mature leaves from the plant. Make sure to sterilize the pruning shears or knife to avoid any infection. Then cut off the selected leaves right from the base.

Pets And Kids Safety

Sansevieria Masoniana can be mildly toxic for humans and animals when chewed or eaten. All parts of the plant contain a toxic compound called Saponin. When ingested, Saponin causes mouth and stomach irritation. It can numb the tongue and mouth and make them swollen.

Common symptoms of plant poisoning include vomiting, diarrhea, nausea, drooling etc. The juices of this plant can also affect some people and cause rashes or dermatitis on skin. So, be sure to take precautions while handling this plant. Avoid direct contact with the cut and exposed parts. Use gloves whenever you are pruning or repotting the plant. Although the consumption is not likely to be fatal, the plant should be kept away from children and pets.


Repotting your whale’s fin plant is necessary to avoid plant overgrowth. It also makes the plant look neat and tidy in a new container. When you see the leaves getting crowded in the pot, it’s time to repot. Usually this needs to be done every 2-3 years. Repotting makes the plant stronger by encouraging a healthy root growth.

Click here for an in-depth guide on repotting a snake plant. Here are the basic steps to repot your Sansevieria Masoniana:

  • Make sure to get a container with drainage holes. It should be 1-1.5 inches wider in diameter than the current pot.
  • Add a thin layer of rocks or pebbles at the bottom to cover drainage holes. Then put a layer of potting medium over that.
  • Carefully remove your plant from its old pot and gently clean off some soil from the roots. Place the plant in a new pot.
  • Then fill the rest of the container with your soil mix. Plant it at the same height as before. Don’t bury the leaves.
  • Finally, water thoroughly and wait for 1-2 weeks before watering again.


Vegetative propagation, means using the parts of a snake plant is a great way to create new baby plants. Furthermore, this can be done in a soil or using water. Sansevieria Masoniana can be propagated by root division or by leaf cuttings. Dividing the roots is the quickest way to propagate, but it needs a mature plant.

  • To propagate by division, first gently remove the plant from its container.
  • Inspect the roots to see where they can be naturally separated. 
  • Using a sharp and sterilized cutter, cut the plant in half. For bigger plants, it’s possible to make more than two sections.
  • Repot each section in a separate container. Water them thoroughly and place them in medium light.

Propagation through leaves is a very easy and popular method. For making new plants from a single leaf, you’ll need some leaf cuttings.

  • Take a long, healthy-looking leaf and cut it to make 3-4 inches long sections. You can leave them for a couple of days to form calluses. Or they can be planted immediately.
  • Plant each section base-side down into the soil or water. The orientation is particularly important for the root formation.
  • Make sure that at least 1 inch of the leaf cutting is under the soil or water.
  • Water the soil whenever it becomes dry. Replace the water in case of water propagation.
  • You’ll have to wait for a month or two until small roots will start growing from the cuttings.
  • After the roots grow 2 inches long, plant them in soil.
  • For detailed information on the propagation process, check out this guide.