How to Plant, Grow, and Care For Kaffir Lime Trees
Kaffir lime trees can make an excellent fruit tree for any home or garden, if you are in the right hardiness zone. They are unique looking, and are sure to be a conversation piece in your yard. In this article, hobby gardener Jason White walks you through each step of how to plant, grow, and care for kaffir lime trees in your garden space.
Unlike the traditional lime trees that most of us know, Citrus hystrix, or kaffir lime trees, are prized for their fragrant leaves instead of their fruit. Many Thai-style curries rely on kaffir lime leaves and rinds for their distinctive flavor. It is also known as the Thai lime, makrut lime, or Mauritius papeda.
Kaffir lime is an ingredient that can be difficult to find anywhere other than specialty supermarkets. Fortunately, you can grow your own leaves to use in the kitchen. A kaffir lime tree can add a whole new dimension of flavor to your meals.
Kaffir lime leaves boast a sharp, citrus flavor that’s similar to a lime. However, they tend to lend a slightly more earthy, floral note to dishes. Many compare the flavor to that of lemongrass, though it’s challenging to replicate the unique taste of these tropical fruits.
Kaffir Lime Tree Plant Overview
Tropical and Subtropical Plants
Don’t Plant With
Bees, Butterflies, Birds
Mites, Scales, Aphids
Spot Fungus, Root Rot, Citrus Canker
History and Cultivation
The kaffir lime tree is a subtropical plant native to Sri Lanka and the Mauritius area. There, the plant is known as papeda. You can find it in a wide variety of traditional local dishes dating back generations.
Early on in its cultivation, the kaffir lime spread to other areas of Southeast Asia. It gained widespread culinary adoption in Thailand, where it’s known as makrut lime. Nowadays, they still play a prominent role in many of the nation’s signature dishes, including Thai curry.
Kaffir lime trees didn’t find their way to the Western world until the late 1800s. A Scottish botanist called H.F. MacMillan brought the fruit from Sri Lanka to his home country, introducing it as the kaffir lime tree.
While the name “kaffir lime” has widespread acceptance, it’s important to note that the term may be considered offensive in certain parts of the world. The word “kaffir” derives from the equally offensive Arabic word “kapiri.” In Sri Lanka, the word had been used for hundreds of years as a racial slur and is still considered offensive around South Africa.
Despite its connotations, kaffir lime is a common term used worldwide, including in South Africa. It is generally not considered offensive. However, many chefs and foodies are shifting to more politically correct alternative names such as the Thai or makrut lime.
This tree is a surprisingly hardy plant that’s easy to propagate, even for beginners. While you can grow a fruiting tree from seed, this method can be challenging. Seeds require optimal conditions to germinate.
Even if your young plant thrives, you can’t guarantee your new tree will behave like its parent. Often, citrus trees propagated from seed fail to fruit at maturity, making cuttings a less risky propagation method. You’ll get a genetic duplicate of the parent, ensuring ripe fruit and fragrant leaves.
Propagation From Cuttings
Cuttings are quick to mature, often fruiting well before trees grow from seeds. While it can take up to ten years for a seedling to reach maturity, cuttings can bear fruit as soon as three years after planting.
You need a young branch from a fruit-bearing tree to propagate a kaffir lime plant from a cutting. It’s best to take cuttings from plants with a history of bearing healthy fruit and producing lush, fragrant leaves.
While you want a fruiting plant, you must choose a branch for your cutting that’s free of fruit, flowers, or early buds. Cut the stem about three inches down from the closest leaf node, and then strip away all foliage from the lower two-thirds of the plant.
You first need to encourage root growth before you can plant a cutting in soil. To do this, place the end of the branch in a container of water. It can help to add wet peat moss to anchor the cutting and encourage healthy growth.
Some gardeners choose to dip the end of fresh cuttings in a specially formulated rooting hormone solution. You can make your own DIY solution at home using ingredients such as apple cider vinegar, or you can purchase rooting hormones at your local nursery.
You can encourage fast, healthy growth by ensuring your cutting has access to plenty of sunlight. However, direct sunlight can be too harsh for a young plant, so keeping the cutting container in partial shade is best.
Heat can also speed up the propagation process. As a subtropical plant, the kaffir lime tree grows best in warm, balmy weather. If you live in the us, southern humid climates in states like Florida make a perfect subtropical tree growing location. Placing a heating mat underneath your plant as its roots can help to encourage rapid growth.
Water new cuttings regularly as they root, especially when growing them in peat moss. If you notice the water level starting to drop, place the container in a bowl with fresh water instead of adding more from the top. Doing this allows roots to soak up just as much as they need without becoming oversaturated. You may also want to mist the plant to ensure it stays hydrated.
Once you notice healthy, white root growth at the bottom of your cutting, you can transfer your tree to the soil. Fill a medium-sized pot with appropriate soil and dig out a hole in the center. Gently place the root ball of your tree in this hollow and cover it with soil to anchor.
Propagation From Seeds
While cuttings have identical genetics to their parent plant, seeds may introduce a wide variety of variations. It can take as long as ten years to know if a seedling will fruit or not.
If you choose to propagate from seed, you may want to grow several different plants to increase your odds of having a fruiting tree. Each seed that you plant may show vastly different growing and flowing patterns.
You can find ready-to-plant seeds online or in specific nurseries. If you already have a kaffir lime tree in your yard, you can harvest some fruit to extract seeds. You must clean all fruit pulp from the seed and allow it to air dry before planting to improve your chances of success.
Place the seed about 1.5 inches deep in specially formulated potting soil. This tree’s seeds tend to grow best in soil formulated for citrus trees. This type of soil contains all the nutrients that they need and offers a hospitable acidic environment for young roots.
As with propagations from cuttings, you need to keep seeds warm and provide plenty of sunlight. If you keep the soil at more than 55°F using a heating mat, it will take around just two weeks for seeds to germinate. Germinating seeds do well in direct sunlight.
It’s also crucial to water growing seeds more than mature plants. While soil shouldn’t be damp or soggy, it should be slightly moist at all times. Once the new seedling seems established, you only need to water around once per week. Soil should feel dry down to the one-inch mark. Otherwise, you run the risk of damaging your new plant through overwatering or root rot.
You can plant kaffir lime trees either in the ground or in a pot. It’s best to only grow them outdoors if you live in a warm, sunny climate. Keep in mind that if you live in a dry area, your tree may need additional watering. They do best in USDA hardiness zones 9-10.
If you choose to plant your tree in the ground, you need to make sure it has plenty of room to grow without facing competition from other plants. You should give trees around six to ten feet of space, regardless of how big they are at the time of planting.
Planting your kaffir lime tree in a pot gives you some mobility throughout the year. If you live somewhere with all four seasons, you can keep your plant outdoors during the summer and move it inside during the cold winter months. Potted trees can also live indoors full-time as long as they get plenty of light.
When planting your tree in a pot, it’s essential to ensure that it has enough room to grow. At the same time, you don’t want the pot to be so large that roots have trouble accessing water.
You should start with a small to medium-sized pot when growing from a seed or cutting. Scale-up as your plant grows. Similar to other dwarf citrus trees, kaffir lime plants don’t get much taller than ten to fifteen feet at most.
Kaffir lime trees are pretty hardy plants, and they don’t require much maintenance to grow. They aren’t as needy as apple trees or pear trees. They make a good plant for gardening beginners and novices. As long as they have access to plenty of warmth, sunlight, and water, these trees will thrive.
You’ll have to set a watering schedule for your plant that keeps the soil moist without drenching the roots. Most kaffir lime tree owners also choose to prune their plants regularly to encourage healthy new growth.
You may have to move your tree around throughout the year to ensure optimal conditions. If it gets cold in the winter, you may have to move it inside the house or near a heater. You may also have to adjust its position to ensure it gets enough sunlight during the day.
As a subtropical plant, the kaffir lime tree does best in full sun. Plants need at least six hours of direct sunlight each day, though they prefer more. Ideally, your tree should be getting ten to twelve hours of full sun daily. They can also live in partial shade, though you may see slower growth.
If you live in a hot, dry climate, the afternoon sun can sometimes be too intense. It can bleach leaves and lead to a parched, wilting plant. It’s best to plant your tree in an area that gets direct sunlight in the early morning or late afternoon when the day is cooler.
If you keep your tree indoors, you should place it next to a window to ensure that it gets enough light. It’s best to choose a south-facing window to get strong, direct sunlight. However, this might not be enough light for a subtropical plant.
Some people choose to supplement natural sunlight with specially designed grow lights. Full-spectrum lights are usually the best choice, though they can be harsh. You may need to rotate your plant to ensure that it doesn’t suffer any burns or bleaching.
Kaffir lime trees, like most citrus trees, are thirsty plants. They need access to plenty of water, especially during the growing season. They also prefer a humid environment, so people living in a dry area may need to give their plants regular mistings.
While they need water to thrive, too much can do more harm than good. These plants are prone to getting root rot in wet soil, which can lead to yellowing, wilting, and eventually, the tree’s death.
You should allow the soil to dry between waterings to avoid drenching your tree. You can test the soil down by touching it or feeling the weight of the pot. If you want a more foolproof method, you can also invest in a water meter to determine how wet the soil is.
In general, mature plants need watering once per week under optimal conditions. If it’s hot or dry out, they may need a more frequent schedule. On the other hand, they may need less water during the winter.
When growing a young tree from a seed or cutting, you’ll have to water the plant more often to establish a healthy root system. You can cut back to a regular once-weekly schedule once the plant establishes itself.
You can tell if you’re overwatering your plant by checking the leaves. Overwatered trees tend to experience wilting and leaf drop. You may also notice fungus or small bugs such as gnats breeding in the soil.
Underwatering can be more difficult to detect. It can also include yellowing and wilting. Instead of leaf drop, though, you’re more likely to notice flower drop. If your tree is having trouble, adjusting its watering schedule will often help.
Because kaffir lime trees are prone to root rot, they need well-drained soil to thrive. It’s best to use loamy soil for this plant. A mixture of sand, silt, and clay allows water to trickle through quickly and freely. Components such as clay also provide extra nutrients that trees need to thrive.
You can mix organic matter into the soil to improve both drainage and nutrient content. When mixing in materials such as compost or manure, make sure to allow for at least six months for the organic components to break down. Otherwise, your soil may contain toxic byproducts that can harm your plant.
This tree tends to grow best in acidic soil. Ideally, the pH should be somewhere between 5 and 6 for plants to thrive. You can quickly lower the pH by using acidifying fertilizer or adding materials such as sphagnum moss.
Like most subtropical plants, the kaffir lime tree prefers an environment similar to its native climate. You should aim to keep your tree at temperatures above 60℉ at all times. Otherwise, you may notice slow, stunted growth.
These trees are cold-sensitive and don’t tolerate frost well. If you live in an area where temperatures drop at night or during the winter, you should move your plant indoors. Otherwise, it may not survive the cold.
When placing your tree back outside in the spring or summer, make the transition gradual. If you don’t, you may shock the plant. Gradually introduce it back outside just a few hours at a time, eventually leaving it out all day once it’s warm enough. Your tree will transition back to its growth cycle, and in mature plants, you may see flowering and fruiting.
Using fertilizer can transform a scrawny, unhealthy tree into a lush, fruit-producing beauty. However, you need to know the right kind of fertilizer for your plant. Kaffir lime trees have specific needs when it comes to available nutrients.
As a citrus plant, kaffir lime trees require more nitrogen than other plants. The best soil will boast around two to three parts nitrogen to potassium and phosphorus content. These will have labels marking them as having a 3-1-1 or 2-1-1 NPK ratio.
It’s also a good idea to look for fertilizers that contain iron, zinc, and manganese. These minerals are crucial for healthy growth and fruiting in citrus plants. Other micronutrients can help encourage growth as well, including magnesium, copper, boron, and more.
With new plants, using a fertilizer can help establish a healthy root system and provide essential nutrients. You should apply citrus fertilizer every month for the first year of growth. Once your tree establishes itself, you can start using fertilizer once every four to six weeks.
It’s best to fertilize in the spring and summer months when your tree is at the peak of its growing season. Cut back on fertilizing by late summer to help your tree prepare itself for the coming winter months. Don’t apply fertilizer at all in the late fall and winter.
Kaffir lime trees are relatively low-maintenance plants. However, if you want to encourage healthy growth, it’s a good idea to set up a pruning schedule when your plant is still young. You should prune every year or two for the best results.
Pruning not only improves the appearance of these trees but also improves airflow and strengthens limbs. It also reduces the risk of disease spreading between leaves and branches. If you’re growing your tree for culinary use, pruning makes it easier to reach the best leaves and fruits.
The best time to prune your plant is after the last frost and before the first bloom. If you see frost damage, make sure to wait until the first new growth appears before pruning your plant.
In most cases, all you need to prune this tree is a set of sharp garden shears or clippers. As a dwarf tree, kaffir limes don’t usually require breaking out the chainsaw like their larger counterparts.
Before pruning, make sure that you pick any remaining fruit that might be on the tree. In most cases, the previous year’s fruit should have all fallen away by the time you pick up the pruning shears.
Remove all damaged, diseased, or dead growth from your tree at the base. It’s best to cut at a 45-degree angle, as this prevents water and debris from getting caught in the open cut. You reduce your risk of inviting fungus, bacteria, and disease.
Pests and Diseases
Kaffir lime trees are relatively hardy plants, but they’re susceptible to many of the same diseases as other citrus trees. Greasy spot fungus is a common disease amongst citrus trees characterized by the appearance of yellowing, greasy spots on leaves. You can treat greasy spot fungus with citrus oil and fungicide.
Root rot is another common condition that can affect trees planted in the ground. Microscopic parasites enter and infect root tissue, leading to cracked, gummy bark, and trunk discoloration. Improving drainage is the best way to prevent foot rot. If you notice a case taking hold, you can usually stop it in its tracks using fungicide.
Citrus cankers are another issue to watch for in kaffir limes. The disease is highly contagious and can spread between different parts of the plant, so it’s essential to treat it as soon as possible. Citrus cankers are easily recognizable, as they leave yellow, ring-shaped lesions on leaves, twigs, and growing fruit. You can find specialty sprays designed to kill bacteria and stop infection.
The scent of citrus deters many pests, so these trees are generally safe from infestation. However, if they’re close to another plant affected by mites or scales, you may see insects on leaves and fruit. You also run the risk of insect infestations when overwatering.
Aphids are perhaps the most common pest affecting kaffir lime trees. Depending on where you live, you may see black citrus aphids, cotton or melon aphids, and spirea aphids. With an infestation, you’ll often find bugs on the underside of mature leaves or new plant growth.
To get rid of pests such as aphids, use the spray from your garden hose to knock them off the plant. In advanced infestations, you may need to turn to horticultural oil or insecticide to kill bugs. Adding diatomaceous earth to potted plants can also help to kill most insects.
Kaffir lime trees are easy to distinguish thanks to their joint, rounded leaves, and small, rough-skinned fruit. The fruits are typically a darker shade of green than traditional ones, with thick, bumpy skin that can be a challenge to peel.
Kaffir limes tend to offer much less juice and pulp than Western limes. They aren’t typically a popular ingredient in foods, though the rind sometimes gets used for zest. Instead, people prize these trees for their leaves.
Leaves boast a floral, fruity fragrance that they transfer to dishes such as Thai curry. By simmering leaves in soup or stock, you can achieve a delicious citrus flavor that’s unlike any other. You remove the leaves before eating in most instances, as they tend to be tough to chew.
The leaves can be used fresh or you can freeze them in an airtight bag for later use with little flavor degradation. You can also dry leaves for long-term storage, though they may lose some potency. You’ll have to increase the number of dry lime leaves you add if it calls for fresh ones for most recipes.
Kaffir lime leaves have uses outside of the kitchen as well. Many people value them as a health and beauty supplement. Not only do they add a clean, fragrant smell to cosmetics, but they can also help to strengthen and condition hair.
Frequently Asked Questions
Will my kaffir lime tree fruit indoors?
As long as your tree has access to enough water and sunlight, it should produce fruit at maturity. For cuttings, this often takes around three years. Plants grown from seed can take up to ten years to fruit either indoors or outdoors.
The more light you give the plant, the faster it will grow. If you’re growing indoors, be sure to place your tree beside a sunny window. Adding grow lights to your setup can also encourage fruiting and improve yield.
How often do they fruit?
Kaffir lime trees produce fruit every year once they reach maturity. Fruit ripens in late winter and is ready for harvest soon after. However, most people don’t use the tough, dry limes of this tree. The main attraction is the leaves, which can be harvested and eaten year-round. Just make sure that you leave enough foliage for plants to absorb a healthy dose of sunlight each day.
Why are my kaffir lime leaves yellowing?
Their leaves can turn from a rich green to pale yellow when they aren’t at their healthiest. Yellowing leaves is most often a sign that you’re overwatering your plant. Cutting back to a once-per-week schedule may be the best way to solve the issue.
Another common cause of yellowing is nutrient deficiency. If there aren’t enough vitamins, minerals, and trace elements in the soil, your plant can suffer. It may also display stunted growth and unhealthy fruit. You can add fertilizer to your soil to boost levels of essential nutrients such as nitrogen for your tree.
In some cases, yellowing can be due to illness or disease. If you notice weak, yellowing areas on your tree, you can remove them to reduce the risk of disease spreading to the rest of the plant. In some cases, using a fungicide or insecticide can help to improve symptoms.
Is kaffir lime safe for animals?
Citrus leaves can be toxic to some pets, particularly cats. You should avoid feeding pets food containing kaffir lime. It’s also a good idea to place trees somewhere out-of-reach to prevent pets from chewing on leaves.
In most cases, you won’t have to worry about your pet trying to get a taste of this particular tree. Dogs and cats alike get turned off by the scent of citrus. Even so, always watch your pet around your plants to ensure that both stay safe and healthy.
Can kaffir lime trees survive the winter?
Kaffir lime is a subtropical plant, and as such, it’s not cold-tolerant. Temperatures below 60℉ can cause damage to the plant’s tissue. If temperatures drop low enough, it will kill even a well-established tree.
Plants can’t survive through the frost of winter when living outdoors. However, owners can take potted plants inside to keep them alive when the weather gets cold. Doing this is the only way to ensure that your tree survives the winter.
Growing a kaffir lime tree can help to spice up your cooking with its zesty, fragrant leaves. It’s an easy plant to grow at any skill level, whether you grow it outside or in a pot. This unique looking plant is sure to compliment your garden space, and start plenty of conversations with guests and fellow gardeners. With the proper care, a kaffir lime tree can continue to add some flavor to your meals for decades to come.