Choose the Right Rambutan Variety for Your Area
For home gardening, choosing a rambutan variety suitable for your climate is critical to success. There are over 200 species of rambutan trees that produce edible fruit, but only a few are suitable for commercial cultivation or home gardens in tropical and subtropical regions. The most common varieties are Rongrien, JitLee, and Mahachanok. These varieties can yield up to 100 pounds of fruit per tree annually in ideal conditions.
In tropical climates with hot weather throughout most of the year, Rongrien and JitLee are excellent choices as they are highly productive and better adapted to the heat. For subtropical regions with cooler winters, Mahachanok is a good option as it can tolerate slightly lower temperatures. It may also produce fruit more quickly, within 2-3 years of planting compared to 3-5 years for other varieties. The rounder, orange-fleshed Mahachanok is also considered by many to be the sweetest rambutan variety with a robust “tropical” flavor.
Whatever variety you choose, be sure to plant your rambutan tree in a location with fertile, well-draining soil and full sun exposure for at least 6 hours per day. With the right conditions and care, your rambutan tree can provide an abundance of exotic fruit for decades.
Prepare the Planting Site with These Simple Steps
Preparing the site before planting a rambutan tree is critical to its healthy growth and future success. Select a location with the following characteristics:
- Fertile, well-drained soil – Rambutan trees need moisture but do not tolerate “wet feet”, so choose a site with soil high in organic matter that drains well. If soil is poorly drained, plant the tree on a slope or consider installing drainage pipes.
- Full sun exposure – For at least 6 hours of direct sunlight per day. Rambutan trees grow best in tropical and subtropical climates with plenty of heat and light.
- Air circulation – Choose an open site without obstacles on any side of the tree. Good air circulation reduces disease and also helps with pollination.
- pH between 5 to 7 – Have your soil tested and amend as needed to reach the proper pH range which supports optimal rambutan growth.
To prepare the site, first remove any vegetation within a diameter of at least 6 feet around the planting hole. Then:
- Loosen the existing soil to a depth of 2 to 3 feet using a rototiller or garden fork. This improves drainage, aeration, and facilitates root growth.
- Amend and enrich the soil with 3 to 6 inches of compost or well-rotted manure. Mix into the loosened soil along with a balanced, all-purpose fertilizer.
- Create a raised planting mound at least 3 feet in diameter for better drainage. The top of the mound should be slightly flattened for the tree.
- Measure and mark planting holes for any rambutan trees you intend to plant. Holes should be at least 2 to 3 feet deep and 3 to 6 feet wide. Space rambutan trees 15 to 20 feet apart.
- Leave the area for 2 to 4 weeks so the soil can settle before planting. Optionally, you can cover it during this period to prevent weed growth.
With the proper site selected and prepared, your rambutan trees will have the best start toward producing a successful harvest. Be sure to maintain the site after planting by watering, fertilizing, and mulching around each tree.
Planting and Caring for Your Rambutan Tree
Once you have selected a suitable variety and properly prepared the planting site, you are ready to plant your rambutan tree. For the best start, choose a healthy, young tree and:
- Dig holes 2 to 3 feet deep and 3 to 6 feet wide, spaced 15 to 20 feet apart. The top of the root ball should be slightly above ground level.
- Place 3 to 6 inches of compost in the bottom of the hole. Do not add more fertilizer at this time.
- Remove the tree from its container and loosen the roots slightly if root bound. Place in the hole, making sure the root ball is level with the surrounding soil.
- Fill the hole with the soil you removed, lightly tamping it down around the base of the tree with your heel as you go to remove air pockets.
- ** Water the tree thoroughly after planting and regularly for the first two years**, especially in hot or dry weather. Rambutan trees need at least 1 to 2 inches of rain per week.
- Apply a balanced, all-purpose fertilizer 4 to 6 weeks after planting. Follow the directions on the product packaging regarding how much and how often to fertilize your rambutan tree based on its age.
- Prune your rambutan tree to establish a strong central leader and wide-angled crotches as it grows. Also remove any dead or crossing branches. Pruning will help maximize fruit production and overall tree health.
- In colder regions, wrap young trees to protect from frost or freeze damage. Wrapping the trunk and especially the graft union will help them survive until well established.
With consistent moisture, fertilizer, and pruning, a young rambutan tree will typically produce fruit 3 to 6 years after planting. Mature trees may yield 100-500 fruit or more each season, and will continue producing for 50-100 years with proper care. Be sure to also periodically check your tree for signs of common pests or disease and treat them promptly to avoid damage. Following these best practices will help ensure your rambutan tree thrives in its new home.
Protecting Your Rambutan Tree from Pests and Diseases
Even with ideal growing conditions, rambutan trees can be susceptible to damage from common pests and diseases. Regular monitoring and prompt treatment is key to avoiding significant harm. Some potential threats to watch for include:
Scale: Armored scale and soft scale insects feed on rambutan leaves and fruit, sucking sap and nutrients from the tree. They appear as immobile bumps on leaves, twigs and fruit. Control with horticultural oil or insecticidal soap sprays.
Mealybugs: Mealybugs are soft-bodied insects that also feed on sap and secret a white wax. They tend to cluster where leaves join twigs. Remove by hand or spray with horticultural oil.
Mites: Mites cause rambutan leaves to become speckled or stippled. They pierce and feed on individual plant cells on the underside of leaves. Increase humidity around trees and spray with sulfur or predatory mite sprays.
Fungal leaf spot: This fungus causes dark, oval leaf spots with yellow halos. It is usually a minor issue but can defoliate trees if left untreated. Apply copper-based fungicide sprays, especially during wet season.
Anthracnose: This fungus infects rambutan flowers, leaves, and fruit. It appears as dark, irregular spots on shoots, and circular spots with dark borders on leaves and fruit. Perform regular pruning for airflow and spray with chlorothalonil fungicide before and during rainy season.
Stem canker: Caused by a fungus, stem canker forms sunken, dark lesions on twigs and branches. As it spreads, it can girdle branches. Prune out infected wood, including a margin of healthy tissue. Disinfect tools to prevent spread. Apply fungicidal paint to wounds.
Monitor your rambutan tree weekly during growing season for signs of pests or disease. Remove infected leaves, twigs or fruit and dispose of them to avoid spread. Apply all pesticides carefully following instructions and safety measures. Protecting your tree properly may require both biological controls as well as chemical sprays for the most severe infestations. With vigilance and prompt action, you can avoid major damage to your rambutan tree from common threats.
Harvesting and Enjoying Your Rambutan Fruits
Once your rambutan tree starts producing fruit, it will continue bearing for 50-100 years or more with proper care. The oblong, red and green spiky fruit take 5-7 months to mature on the tree before they are ready to harvest. Follow these tips for harvesting and enjoying your rambutan fruits:
- Check for ripe fruit daily during harvest season. Rambutans ripen quickly on the tree so frequent monitoring is important.
- Look for clusters with 4-6 fruits that have turned mostly bright red. The green spines should look fresh, not dried out. Gently squeeze the fruit to check for a slight softness.
- Twist the fruit gently from the stem to pick. Do not cut the fruit from the tree or branch which can damage future harvests.
- Peel off the thick, leathery skin immediately before enjoying or storing the fruit. The hairy spines irritate the throat and are unpleasant to eat.
- Separate the fleshy Fruit arils into halves they are attached at a single seed. The translucent flesh has a sweet, tropical flavor with hints of grape or melon. Discard the bitter seed.
- Eat rambutans fresh for the best flavor and texture. They also work well in fruit salads, jams, and desserts. Fresh rambutans will last 2-3 days refrigerated.
- Consider canning or freezing excess harvest if you have a large crop. Properly canned or frozen rambutans can last 6-12 months.
Rambutan trees may produce 100 lbs or more of fruit per season, so sharing your harvest with friends and family or donating extra to local food banks are excellent ways to avoid waste.
The unusual yet delicious rambutan fruit is a tropical treat. With annual pruning, fertilizing, and pest management, a mature rambutan tree can provide an abundance of fruit for decades. Enjoying the fruits of your labor caring for this exotic tree makes all the effort worthwhile. Rambutans can be a uniquely rewarding fruit for home growers in tropical and subtropical climates.