How to Plant, Grow and Care For Rambutan Trees
If you live in the US or Europe, you might be wondering what on earth a rambutan tree is. It’s a heat-loving tropical plant that needs to grow in USDA hardiness zone 10 or higher, so many of you may only be able to buy them online or in specialty farmers’ markets. They’re related to lychees and grow hairy-looking fruits that you peel to reveal sweet flesh that’s a lot like grapes. Yum!
While you may never grow a rambutan tree in your backyard in the majority of the US, you can give it a try in a climate-controlled greenhouse. This tree loves warm weather and lots of humidity, so you’ll need a moist environment for it to grow in or for it to bear fruit.
If you live in the perfect rambutan climate or want to try your luck with some tropical fruits, read the following guide to growing this unique tree.
Quick Care Guide
|Rambutan, hairy lychee
|Days to Harvest
|Full sun or 13 hours of partial shade
|Keep soil moist
|Well-draining loamy soil with a pH of 5.5-6.5
|Heavy fertilizer needs that vary throughout the year
|Bats, birds, oriental fruit fly, green weevils, leaf-footed bugs, leaf miners, lychee giant stink bugs, mango twig borers, mealybugs
|Powdery mildew, stem canker
All About The Rambutan Tree
The rambutan tree (Nephelium lappaceum) originates from southeast Asia and can be found in the coastal lowlands of China, Thailand, Vietnam, and other surrounding countries at sea level. Temperatures under 50°F can kill the tree, so it’s no wonder why it’s considered to be so exotic in Western countries! It has since spread to southern Mexico and Central America, specifically in Costa Rica.
Rambutan fruit is sometimes called hairy lychee because of its similar appearance to lychee. (After all, they are closely-related cousins coming from the Sapindaceae family.) The soft spines create a hairy appearance, but the skin is red, and the flesh is white, just like lychee. The taste is sweet with a bit of a tang, much like grapes or strawberries.
When these trees are grown in the perfect habitat, their spreading crown can range from 32-82 feet tall! Growing them in a medium-sized to small pot in a greenhouse will likely result in a smaller tree, but you’ll still be able to get delicious fruit.
The tree has glossy green leaves with a slightly leathery feel that can sometimes be yellow-green. Although the fruit is typically red and white, the outside can sometimes look orange or yellow, and the inside may occasionally be pale pink.
After peeling the fruit, they can be eaten raw or cooked and canned in syrup. They’re often extremely sweet and can be enjoyed as a dessert, but they are full of vitamin C. The roots and bark are often used in natural medicine, and the seed oils can be used to make candles and soap. Silk can be dyed green with young tree shoots.
The Malay word rambut translates to hair in English, and the name, Rambutan refers to the hairy appearance of the fruits. These fruits appear after budded trees flower. Flowering occurs on male trees, female trees, or hermaphroditic trees in spring through summer and again in late summer through fall. The flowers are pollinated by ants and bees.
The easiest way to get a rambutan tree growing is to start from seed indoors in a container. They require TLC from every single seed to transplant, so keeping them in a controlled environment will be the best way to increase your chance of success.
Rambutan seeds are only viable for up to one week after being harvested, so you’ll need to act fast once you get your seed. Remove the fruit from the seed and let it dry completely.
Place the seed in sandy, loamy soil with good drainage. Even though rambutans like humidity and lots of water, there’s still such a thing as too much water, especially when they’re young.
Cover the seed with a light layer of soil and water it well. Make sure the soil stays moist but not wet, and keep the seed under a grow light. It can take 10-21 days for it to sprout, so don’t worry if it takes a while.
Once the tree sprouts, keep it indoors with moist soil and lots of light. It won’t be ready to move outside until it’s about 1 foot tall in about 2 years and won’t produce fruit until it’s 4 or 5 years old.
You can plant the seed any time of year if you’re growing it indoors, and when it’s time to transplant, you can do so in early spring.
Caring for a Rambutan Tree
A rambutan plant needs lots of care, especially if you’re attempting to grow it in a cooler zone than it likes. Let’s take a look at what this fruit tree needs to thrive.
Sun and Temperature
If you can provide full sun and temperatures over 60°F all year long, you can grow rambutan with very few problems. If full sun isn’t an option, it can make do with 13 hours of partial sun, meaning that it gets a little sun every hour for 13 hours. You may have to plug in some grow lights to achieve this.
Rambutan can grow in USDA zones 10 or warmer, so the only places in the US you can grow them outside are Hawaii and the southernmost parts of Florida, Texas, and California.
If you want to grow it in a greenhouse, you’ll probably need one that will allow you to control the temperature and humidity to create a rambutan “oasis.” Aim for at least 60°F. While trees can survive at 50 degrees or warmer, they will not be happy, and at 46 degrees, they can start to lose leaves. At 39 degrees, severe damage will occur to your plant, so it’s really best to keep the temperatures above 50 when possible!
Water and Humidity
Those of you in a dry environment will certainly need a greenhouse, as the prime humidity range is 75-80%. Rambutans prefer a year-round rainy season in their native climate, and they’re going to want you to provide that for them too!
Despite all that humidity, it will need at least an inch of water each week to keep the soil moist, and likely more. If you’re growing outdoors, you probably won’t have to water it if it rained recently or if you’re in a rainy season. But those of you growing them indoors will need to stay on top of your watering schedule.
It’s better to water rambutans a little bit several times instead of one deep water, so you may need to water twice a week in some cases.
It’s best to water in the morning at the base of your tree so the roots can soak up the water before the sun starts to evaporate it.
Well-draining soil is important so the roots don’t get too wet, so choose a sandy loam or clay loam soil to make sure excess water can run off. Rambutan like a slightly acidic soil high in organic matter with a pH of 5.5-6.5.
If you’re growing outdoors, you’ll need a depth of 6-9 feet of soil since the tree grows deep roots. If you’re growing indoors, allow your plant as much depth as possible in a large container. Container trees won’t reach the massive size of outdoor trees, though, so they likely won’t have that big of a root system.
Fertilizing rambutans can be a bit tricky, as there are different ways you can go about it, but each method is specific.
You can opt for a yearly application where you give it 60g of urea, 115g phosphate, and 55g potash for the first year. Once it’s two years old, increase the amount to 180g urea, 345g phosphate, and 165g potash. Beginning at the three-year mark, give your tree 300g urea, 575g phosphate, and 275g potash every six months.
Another method for mature fruiting trees is to use general-purpose water-soluble fertilizer throughout the year.
Give it a 15-30-15 fertilizer in the winter months before it starts fruiting to promote fruit, a 20-10-30 after it flowers to help the setting fruit, and a 20-20-20 fertilizer 1-2 weeks after you’re finished picking fruit to help it recover and grow more fruit next year.
Pruning Your Rambutan Tree
Rambutans will only need pruning to keep them healthy. While the tree isn’t fruiting, remove dead or diseased branches and any branches that look unkempt if you’d like to shape it. Be careful to only remove older growth while it’s not flowering so you won’t lose any fruit.
If you’re growing a tree in a greenhouse, you can prune a young tree to keep it compact. While the tree is dormant in the early winter, cut a 45-degree angle at about knee height. Doing this will encourage it to keep a small growth habit, which is perfect if you have a smaller greenhouse.
Growing rambutans from a single Nephelium lappaceum seed is a long and somewhat difficult process, but if you can find seeds that germinate well, it’s certainly an option for propagation. This is also the easiest way to make more trees if you only have one.
Budding is when you take the flower bud of one plant and graft it onto another. This will only work if you already have two or three trees, though, so it may not be the most feasible choice. Grafting is another choice, but it will also include two trees. Grafting is similar to budding, except it involves branches and cutting them to fit onto existing trees.
A third option is air layering (shown above), wherein you convince a young stem to develop roots. This method enables you to start a propagation on a living branch on the tree, then later cut and remove it below the area where it has developed roots and plant the new start.
Harvesting and Storing
Rambutan fruit (called rambut, the Malay word for hair) is best eaten fresh, so you may not have any left to store after you harvest them! But just in case you have some extra, we’ll cover how you can save your fresh fruit.
Rambutan fruit is ready to harvest when the fruit is mostly red and firm and 1 inch in diameter. The tree won’t form all the fruit at once, so you’ll need to harvest 2-3 times per week while it’s fruiting.
Use a knife or garden shears to cut the stems the fruit is hanging onto. Leave the fruit attached to a stem to reduce the risk of damaging them. A common method for harvesting fruit from tall trees is to attach a knife and a basket to the end of a long pole so the fruit will drop into the basket.
Keep the fruit in the skin until you’re ready to eat it to preserve the flesh inside. They’ll stay fresh on the counter for up to 2 days, or you can store them in the fridge for up to 2 weeks in a container or plastic bag. Many people love cold rambutan, so this may end up being your favorite method!
If you harvested more rambutan than you can eat, you can store them in a freezer bag for about 3 months. Lay them out on a baking sheet and freeze them.
Once they’re fully frozen, you can transfer them into a freezer bag. Using a baking sheet first will prevent them from clumping into one big rambutan ice block. Freezing them without the skins is an option, but leaving the skins on will give them an extra layer of protection.
You can also cook them into a syrup and can them for some super sweet rambutan preserves. These are packed with sweetness and Vitamin C.
There are a handful of things that could grow wrong (pun intended), including a few pests and diseases, so it’s good to know what to expect beforehand. Let’s take a look at how you can prevent pests and other problems.
Rambutan trees don’t have a lot of growing problems, but water, sunlight, and temperature are sure to be problems if you live in zone 9 or below.
Remember that these trees need ideally 60°F temperatures to stay healthy and will begin to decline in lower temperatures. They need plenty of water but don’t allow the roots to sit in puddles. Use grow lights to allow as much sun as possible.
If your tree is struggling, monitor the temperature and take note of how much sun and water it’s getting to determine what the issue is. They’re heavy feeders and need a lot of fertilizer, so they could be lacking nutrients if they’re growing slowly or not producing fruit.
There are several critters that are out to get your rambutans, and birds and bats are one of them! They like to eat the fruit while they’re in the trees, so you can cover fruit with small organza drawstring bags or apply kaolin clay to keep them away. Many gardeners hang reflective decor in their trees to keep birds at bay.
Many pests will cause damage to the dark green leaves by eating leaf tissue or sucking sap. Pests that like rambutan include green weevils, leaf-footed bugs, lychee giant stink bugs, leaf miners, and mealybugs. Washing them off with water is an easy way to get rid of them, but you can also use neem oil to suffocate them or use insecticides for each kind of pest to kill them.
Oriental fruit flies go after ripe fruits, and mango twig borers go after developing fruits. Organza bags will keep twig borers away, and be sure to harvest as soon as they’re ready to prevent flies.
There aren’t many disease issues with rambutan trees, but you may find powdery mildew and stem canker to be problems.
Both of these are fungal issues that can be prevented with fungicides. Unfortunately, these diseases don’t have a cure, so you’ll need to remove infected plants. You can try removing only the infected portion of the plant to see if you can save what’s left.
Frequently Asked Questions
Q: Can you grow rambutan in the US?
A: You can grow rambutan outside in USDA zones 10 and up or in greenhouses in cooler climates.
Q: How long does it take for a rambutan tree to bear fruit?
A: A rambutan won’t produce fruit until it’s 4-5 years old.
Q: Where do rambutan trees grow?
A: Rambutan trees are native to eastern Asia.
Q: How tall do rambutan trees grow?
A: Full-sized trees can grow 32-82 feet tall but will be much smaller when grown in a medium-sized to small pot.
Q: Are lychee and rambutan the same?
A: They’re not the same, but they’re similar! They both come from the same family, Sapindaceae.
Q: What is the life span of rambutan?
A: Rambutan usually fruits for 15-20 years, although in some cases, they can last for 60 years.
Q: Are rambutan self pollinating?
A: Rambutan trees need to be cross-pollinated. However, some trees are hermaphroditic and have both male and female flowers.
Q: How can you tell if a rambutan tree is male or female?
A: It’s difficult to tell because you have to wait and see if it will produce fruit after flowering. Look for labeled plants at a nursery or grow a few trees at once.