How to Care for Imperata cylindrica (Japanese Blood Grass)

Imperata cylindrica is also known as the Japanese Blood Grass, Cogon Grass, and Kunai Grass is a perennial shrub, native to the subtropical and tropical regions of Asia, Australia, and Africa. It is called Japanese Blood Grass because of its origin (Japan) and the color of foliage that reflects a red color. This grass has also been introduced to different other parts of the world, including America, and the Caribbean.

The Japanese Blood Grass is considered a beautiful choice for your garden boundary, a landscape near the lake or to create a beautiful outlook of your lawn. This grass can adapt to a variety of different environments. The Japanese Blood Grass is considered a very flammable plant, it is also adapted to the regeneration after being burned.

The Japanese Blood Grass is one of the easy to grow plants, but it is very hard to kill or remove it from the place it was planted. That is why in some areas, it is also considered as weed grass. But due to its beautiful appearance that creates a scenic beauty, it is grown worldwide. They have also adapted to the indoor environments, so if you have a place indoors you can easily grow them.

Japanese Blood Grass also grows small-sized flowers that grow on the tip of the stalk. The beautiful texture, the color of the foliage, and when you see them from a distance, they will feel like a mix of colors is moving. The Japanese Blood Grass quickly grows and spreads all around the place, so if you are looking forward to growing them in your garden or any area, you will have to confine them with a proper boundary to control their spread.

The Japanese Blood Grass can get up to 18 inches in height. The plant spreads with the help of rhizomes (underground stem). It has large rhizomes and roots that can get very deep inside the soil, they can obtain water from very deep below the soil once the plant has been established in the soil.

Growing Conditions and Requirements

Japanese Blood Grass is one of the easiest ornamental plants to grow, you can just plant them in any type of soil, and they will grow on their own. They need a slightly cold environment, a damp soil, and full sun to partial shade to thrive.

They grow a green foliage color that gradually turns into the blood-red color as the plant grows. The Japanese Blood Grass requires very low maintenance and mostly can grow on its own once it has been planted in the soil. But with proper care, you can get even better results.

Below are the details about the growing conditions and requirements:

Water Requirements

Japanese Blood Grass needs more watering in its early days, but once its roots are established deep in the soil, it can get water on its own and becomes drought-tolerant for a short time. You can water them based on seasonal, age, and height requirements.

●     Small Japanese Blood Grass plants need more water, while the large and grown-up plants can be watered occasionally. You can water the young plants once every week, while to the grown-up grass, watering once every 10 to 15 days will be enough.

●     In hot and dry weather, they need more water than the cold and wet days. You need to water them according to the seasonal basis. If it is summer, and days are hot, you will need to water them more frequently. But when it is cold during the winter, you can water them less often.

●     As they are grown in a garden, field, or landscape, you need to openly irrigate them, do not use the shower, or sprinklers to water them. Moisture on the leaves and stems of the Japanese Blood Grass can attract different types of molds and fungus. They cause severe damage to the foliage.

You can prepare a watering schedule for them as well. This watering schedule must be prepared according to seasonal and environmental factors. You can also include the age and height of the plant as well.

Lighting Requirements

Japanese Blood Grass needs to be grown in a bright environment. They thrive under the full sunlight. You can grow them easily in outdoor environments where they can get enough light. They can also be grown in indoor environments and places where light is abundant. 

Japanese Blood Grass can also be grown in shady places. In shady areas, the plants will grow very well, but the foliage color will not be the same as the outdoor plants. You can also plant them under the shade of other trees if you are growing them in your backyard or garden. But you will have to make sure that they get direct or indirect sunlight for almost 6 hours a day.

If they are completely or partially grown under the shade, or dark environments, where they were unable to get the required amount of sunlight, they will show slow growth. Apart from the slow growth, the Japanese Blood Grass will be prone to bacterial and fungal attacks.

Temperature Requirements

The Japanese Blood Grass is a native to the cold region. It can be grown in the areas where temperatures during the winter can go below zero. They grow very well USDA zone 5 to 9. The minimum temperature where you can grow them is -20 F.

They are pretty much cold hardy and frost hardy as well. They can also be grown in moderately hot zones as well. In areas where temperatures during the summer can get higher than 80 F, they must be planted indoors or protected from the extreme heat of the sun.

Soil Requirements

A well-draining soil is considered a good choice for the Japanese Blood Grass. Such soil is porous and allows the quick drainage of water. This type of soil also does not trap the water for the long term. Making it a perfect soil for the Japanese Blood Grass. The soil can be of any type, alkaline, acidic, or neutral.

This type of soil mostly contains the cocopeat, perlite, pumice sand, and mulch. You can also add some plant fertilizers. You can also grow them in the garden soil if your garden soil is sandy and quickly drains the water.

Fertilizer Requirements

The Japanese Blood Grass is a quickly growing species, they need a soil that is rich in nutrients and contains all the essentials for its growth. During the growth of the Japanese Blood Grass, these nutrients of the soil quickly deplete and the plant needs an extra amount of nutrients. You can provide these nutrients to the plant in terms of plant fertilizers.

Before applying any type of fertilizer conduct a soil test to know which are the nutrients that your soil lacks. You can use a fertilizer that contains those nutrients and add them into the soil. There are three different ways to fertilize your Japanese Blood Grass plants.

1.    The first method is used before the plantation of the Japanese Blood Grass. The fertilizer is mixed with the soil in which the Japanese Blood Grass will be planted. You can take a required amount of required fertilizer and simply mix it with your ground soil. Provide it some water so that the soil can absorb the fertilizer. Once the fertilizer is absorbed, you can plant the Japanese Blood Grass. This method is considered a very helpful method to promote an early-stage growth of the Japanese Blood Grass plants.

2.    The second method involves spreading the fertilizer in the soil after the plants have been planted. This method is used when you feel that your Japanese Blood Grass plants are not showing proper growth. In this method, you take a required amount of plant fertilizer, and then you can simply spread it.

3.    The third method involves creating a mixture of plant fertilizer and water and then feeding it to the plants. You can feed this mixture to your Japanese Blood Grass regularly once every 50 days.

Before applying any plant fertilizers, you must have a soil test otherwise you will not be able to efficiently use the fertilizers. You can use the proper guidelines and usage instructions, only use according to the recommended methods. Guidelines and usage instructions are mostly written on fertilizer bags.

Pruning Requirements (how to control the spread):

Japanese Blood Grass plants do not need pruning, but you can do this to control their spread. You can cut off the extra plants that are growing like a weed. You can also cut off the dead or diseased plants as well. This is more like controlling the spread of the Japanese Blood Grass.

If you do not control their spread, or allow them to grow freely without any pruning or control, they will take over all other plants and your garden will look like a weed grass field. Grow them in a confined place, draw a boundary line around them. This will help you control their spread from rhizomes. In a confined place, the rhizomes will remain at the same place and will not spread, you can also cut off the extra plants and rhizomes.

Once you see them spreading wildly, you can start pruning them and cutting them off. When you are cutting them, make sure that you also cut off the rhizome and get it out of the ground. If the rhizome remains in the soil, there are chances that in favorable conditions, the grass will grow again.

Common Diseases and Pests Control

Root Rot, Snails, Slugs, Fungi attacks, and leaf Rust are a few common problems. They mostly occur if the plant is not grown properly. Root rot happens due to the improper watering of the plants. If you are overwatering or overfeeding the fertilizers, these can lead to the root rot. It can sometimes kill the plant as well. The only way to prevent this is by properly watering the Japanese Blood Grass plants.

Snails and slugs also attack the foliage of the plants and eat the leaves. Their attacks are not severe and you do not need to worry about them, but if there are too many snails and slugs you can use the chemical sprays to control the population.

Fungi attacks and leaf rust are also common problems that mostly happen if the foliage of the plant is wet. During the rainy days, the foliage of the plant becomes wet and this attracts fungi to attack the leaves. This leads to the rusting of leaves. You can prevent this by protecting the foliage of your Japanese Blood Grass from the wetness and moisture.

How to Plant

You can easily plant the Japanese Blood Grass with the help of its underground stems (rhizomes). These rhizomes can be easily divided and then replanted after division and they grow into a new plant. To grow them from rhizomes, you need to spot a mature plant that has no signs of any illness.

You can uproot the plant, and divide its underground stem with the help of a sharp sterile knife and then plant the divided rhizomes into well-draining soil. Provide them some water and keep them in a slightly warm environment.

Growing from seeds:

The seeds of the Japanese Blood Grass can be obtained from the online stores and nurseries. You can sow these seeds during the spring season. Place the seeds in the soil and provide them some water. Cover the pot with the plastic sheet, and keep them warm and moist. They will germinate in a few days. Once they are out of the soil, you can replant them into the ground or any place where you want to keep them.

Frequently Asked Questions

Question: How to Kill/remove Japanese Blood Grass?

Answer: The Japanese Blood Grass if not grown properly and not taken care of, can become a weed and spread all over the place. It becomes very difficult to remove it as it has very deep roots and its seeds keep on spreading. You can kill or remove the Japanese Blood Grass from your Garden by uprooting the plants and killing the rhizomes as well. You can also have the herbicides sprayed on them.

Question: What is the botanical name of Japanese Blood Grass?

Answer: The Botanical name or the scientific name of the Japanese Blood Grass is Imperata cylindrica. It has many common names in different areas but its botanical name is also its universal name.

Question: Can I grow Japanese Blood Grass in Pots?

Answer: yes, it is possible, you can grow the Japanese Blood Grass into the pots. But this will require more care. If you can provide them full sun to a partial shade environment, proper watering, fertilizers, pruning, and protection from diseases, you can successfully grow them in pots as well.

Question: Is Japanese Blood Grass a perennial?

Answer: Yes, Japanese Blood Grass is a perennial plant that is grown for its beautiful red-colored foliage.