Bamboo plants are vigorous growers that can survive in a wide range of environments. They are often known for their ability to spread quickly and aggressively. Even slower-growing clumping varieties can establish themselves quickly in the right conditions. While they are versatile and hardy, however, they are not invincible. Like any plant, bamboo plants have needs that must be met to stay healthy and can turn yellow to signal that they are struggling.
Why Is My Bamboo Turning Yellow?
When a plant’s leaves or stems begin to turn yellow, it can be a sign that something is wrong. Usually, it means that the plant needs more or less of something or is growing in conditions that are not ideal. While bamboo can exhibit yellowing when in distress, there are also parts of its life cycle when yellowing leaves are completely normal.
Below, we’ll list a few of the most common reasons that your bamboo plant might be turning yellow and help you adjust your care routine if necessary.
Normal Reasons for Yellowing Bamboo
Before you start to worry, you should know that there are a couple of reasons that bamboo will turn yellow under normal, healthy circumstances. Although bamboo plants are evergreen, they still shed their leaves. However, unlike deciduous plants, they do not lose them all at once. Many of the leaves will turn yellow in the spring before the plant drops them to make room for the new year’s growth.
There are also some species of bamboo, like Phyllostachys aurea, whose culms turn yellow with age. Another species in the same genus, Phyllostachys aureosulcata, has a groove along each internode that will turn yellow as well. In addition, bamboo culms do not live forever. While the rhizome of a healthy plant will continue to spread underground, culms will eventually become “spent” and die back after several years. When this happens, they begin to turn yellow or tan before finally becoming grey or brown. This is part of your plant’s normal life cycle and as long as it isn’t happening en masse, there’s nothing to worry about.
If you have just planted your bamboo, it may be turning yellow due to transplant shock. This condition can occur when a plant is moved to a new environment. Transplant shock occurs most prominently in plants that have been newly divided as well as those that have been moved with too little of their original soil. If you are taking a division yourself, you should leave as much soil as you can handle around the base of the plant. You should also make as clean a cut as possible through an internode of the rhizome. Ideally, you’ll make your cut in a single pass with a sharp tool. Some good pruners or a sharpened spade are usually enough for this task, but you may want to use a sharp saw to cut through larger rhizomes.
When selecting bamboo plants for your garden or landscape, you should seek out those that have been allowed to heal after division in the nursery. These plants are better equipped to handle transport as well as the stresses that come with transplanting. Oftentimes, bamboo plants sold at a nursery are only a few feet tall. This is good, as shorter plants are often less complicated to transport. If your new plant has narrow, flexible culms, you may be able to gently bend them so that they fit in a vehicle. If you must transport a larger plant in an open-bed truck, you can wrap the branches and leaves with plastic wrap to protect them from the wind.
You can help your new bamboo plant transition into its new environment by planting on a mild day. Overcast skies and lack of wind are ideal. You should also be sure to support your new bamboo if necessary to keep it standing upright.
One of the most common reasons that a bamboo plant begins to yellow is due to improper watering. Because of how quickly it grows, bamboo requires a lot of water — usually about an inch per week. However, if your soil does not drain quickly enough, it is easy to over-water your plants. Therefore, you must monitor your bamboo’s soil conditions and adjust your watering routine to meet its needs.
If you suspect that over- or under-watering is the cause of your troubles, there are a couple of things that might help you get back on track. You can use the top couple of inches of soil as an indicator of when to water. Once this top layer has dried out, you should give your plants a good soak. Be sure to avoid creating puddles, however, as bamboo cannot survive in standing water for long periods. Bamboo rhizomes must stay oxygenated, so overly wet soil that prevents air from reaching the roots will harm your plants. Anaerobic conditions like those that occur in wet soils also put your bamboo plant at risk of contracting root rot.
In more severe cases, such as when a plant is growing in a flood-prone area, you may need to do more work to correct the problem. You may need to move your bamboo plant to a new location, or else adjust your landscape to allow for better drainage.
Depending on the species of bamboo you have chosen, too much or too little sunlight can put a strain on your plant. Some bamboo plants grow naturally in tropical understories or along wood lines and cannot handle the harsh, direct sun. Others, like the gargantuan timber bamboo, need a wealth of sunlight to reach their towering heights. If you have chosen a spot for your bamboo that doesn’t meet its needs, you may need to move it.
Remember that transplanting bamboo causes a lot of stress on its rhizome, however, and can even kill younger, less established plants. The shock can also cause your plant to abandon the culms it has already produced. Therefore you should aim to avoid transplanting and choose the ideal spot for your specific bamboo variety before you even plant it.
Yellowing foliage is not the only indication that your bamboo is struggling with its lighting needs. In intense sunlight, leaves can become scorched or otherwise curl up to prevent burning and excess moisture loss. Sunlight exposure also causes soils to dry up more quickly making it even more important that you monitor your plants and water them accordingly. While mulching is a best practice in all cases, it is especially helpful with moisture retention in bright, open spaces. Not only does it help prevent your soil from drying out, but it also keeps it cool and protects the vital microbial communities that thrive in your plant’s root zone.
Lack of Nutrients
Bamboo, being the fastest-growing plant in the world, requires a lot of nutrients to produce and maintain healthy growth. If your soil is overly sandy, compacted, or lacking in organic material, your bamboo may turn yellow as it struggles to obtain the nutrients it needs. Chemical fertilizers can help alleviate your plant’s nutrient deficiency in the short term, with consistent application of top-dressings providing long-term support.
Instead of only feeding your plants with chemical fertilizers, you can support healthy growth as well by applying nutrient-rich top dressings. Leaves, dried grass clippings, straws, and wood chips all make for good mulch. The addition of small amounts of animal manure or well-composted organic material will supplement your soil with the nutrients your plants need. One of the best parts about supplying nutrients in this way is that your soil remains virtually undisturbed. By taking this approach, you allow vital populations of bacteria, fungi, and protozoa to establish themselves. In turn, these microbes build soil diversity, drive healthy decomposition, and release nutrients for your plants over time.
Pests and Disease
While bamboo plants tend to be resistant to pests, there is still the possibility of an infestation. Although it is not very common, an aphid infestation can cause your bamboo leaves to turn yellow. As they feed on the underside of your plant’s leaves, aphids damage leaf tissue. This can cause leaves to drop off as well.
The disease is oftentimes a secondary problem. For example, stressed plants are more vulnerable to aphid infestation. Aphids, as they damage the plant, leave honeydew on the undersides of the leaves. This sugary waste then acts as a food source for fungi like black sooty mold, which can prevent leaves from absorbing sunlight. If this infection becomes bad enough, it can cause leaves to yellow and drop off.
Improper watering techniques can also contribute directly to infections. When watering your bamboo, be sure to water it at the base of the plant and avoid wetting foliage. Excess moisture on leaf surfaces can encourage powdery mildew growth. This is especially important to remember if your bamboo variety prefers shadier conditions, as water droplets will not evaporate as quickly.
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