Wax Jambu 

(syzygium samarangense)

(AKA: Eugenia javanica)

 

Wax Jambu tree overview:

• The Wax Jambu is a dense evergreen tree that produces an abundance of beautiful and refreshing fruit.

Note: This plant/fruit is known by many names (see the bottom of this article for a list of names). I don’t think that one name is necessarily better than another.  However, I will mainly use the name Wax Jambu in this article for convenience.

Wax Jambu fruit appearance:

Fruit Shape:

• The fruit is basically bell-shaped.
• The bottom part of the bell often has what looks like a little beard.  This is hair is basically the dried up remnants of the flower’s stamen and it is easily removed with a blast of water. I have also noticed that ants like to hide out in this area though, so it is not a bad idea to blast the fruit with water outside your home.

Fruit Color:

• Different varieties of Wax Jambu will have different colors of mature fruit that range from white, pale green, green to red, pink, red, purple, deep purple and even black.
• This variation in options is pretty cool, but can be challenging if you mix up your plant identification at harvest time. This is because most of the darker color fruit will go through the color stages of other fruit before it is ripe.  For example, the red fruit I have starts off pale green, then turns to pink before it gets to the optimal ripe color of red.
• The skin of the fruit is easily damaged and therefore commercial transport is challenging.
• I have also noticed that young fruit can get sunburn when developing.  This makes the fruit brown, soft and deformed on the sunburnt side.   However, full sun exposure does not seem to bother more mature/colored fruit.

Fruit Size:

• The fruit can range in size from about 5–8 cm long.

Fruit Inside:

• The flesh is white.
• The flesh is dense on the outside and fluffy on the inside.

 

Below is a pictorial progression of fruit formation;

from flower to ripe fruit.

 

Wax Jambu fruit taste:

Texture:

• The Wax Jambu fruit is crisp and refreshing; Imagine a very crisp and light apple… and then take that idea further.
• Overall, the fruit is pretty light weight.  However, the outer of the fruit most dense and it is surprisingly juicy.
• The inner-core part of the fruit is a fluffy-almost spongy mesh.
• This central fluffy stuff surrounds a seed (if a seed is present).

Flavor:

• The outer layer of the fruit is also where most of the flavor is.
• The flavor is very light, mildly sweet, not tart.
• The best way I can describe the flavor is that of rose water.

 

Wax Jambu fruit season: 

• For me, the main season in Southern California has been July to September.  However, flowers and fruit continue to appear past this date.  They will keep going as long as there is enough warmth and moisture.

• Knowing the specific variety of fruit you have will be very helpful when trying to determine the optimal color/time for ripeness (see the section above titled “Wax Jambu fruit appearance”).
• However, regardless of the expected color of the fruit when ripe, the fruit will develop a glossy sheen when ready.
• That sheen, can look a bit waxy… thus some of the common names for the fruit (wax jambu, wax apple)

• I have seen several references that state that a single tree can produce as much as 700 pounds of fruit per year. Considering how light this fruit is, that is a whole lot of produce!

 

Landscaping use: 

• The Wax Jambu is a fast growing tropical shrubby-tree with dense evergreen foliage.
• The tree is said to grow up to 12 m tall in the tropics.  However, I suspect that the mature height in California would be less.
• Depending on the time of year, the numerous flowers or bright fruit hanging on the tree can be beautiful sight for your yard.

• The tree can produce a lot of fruit per branch.  As a result, top branches can be bent down to the ground and sometimes break from the weight of the fruit.  Thinning out the fruit or supporting the heavy fruit-laden branches is likely a good idea.

Flowers:

• The Wax Jambu flowers are pretty cool looking.
• The flowers almost look like white pompoms or something you might see in a James Cameron movie.
• I have seen images of trees in the tropics where the flowers can be found on nearly every part of the trees trunk or branches.  However, around here, I have only noticed the flowers and fruit growing at the ends of branches.
• Flowers often form from June to August.

 

Pollination:

• In my area, honey bees seem to be the major visitor of this flower.

 

Propagation:

Branch cuttings:

• About a year ago, I accidentally broke off a small Wax Jambu branch while messing around.
• So then I felt bad… and I put the broken branch in some ordinary tap water by the window.
• To my amazement, the thing rooted (a lot).
• I put the rooted branch in a container with ordinary soil and then transplanted the new tree my the yard.
• The only initial problem was sunburn on the leaves when I moved it from my kitchen window to out in the yard.
• Otherwise, this unexpected-free new tree is growing great!
  • (see pictures below of the growing progression one newly rooted  plant)
• So my point here is that it seems pretty darn easy to propagate this plant.

Seeds:

• Some seeds look small and I suspect that these small ones are either immature or aborted.
• However, some seeds are rather robust looking and took like they would also grow easily.
• I’ll work on growing some from seed as one of my next projects.

Soil:

• I have seen a rather wide range of soil suggestions for the Wax Jambu.
• Therefore, I did what has worked for me in the past for my other fruit trees;  I aggressively augmented my soil with grow mulch/compost, and inoculated the roots with Micorriza.  Click here for the planting method that I have used for my other fruit trees with great success.

 

Water:

• I water most of my plants 3x week in the summer.
• For established trees, I back way off in the wet winters.
• Covering the ground around the base of the tree with a good layer of wood mulch will help to retain moisture in the summer.
• I also suspect that this plant needs well draining soil.
• I have all of my Wax Jambu trees on some sort of slope. This allows excellent drainage and also avoids the collection of cold air in the winter.

 

Sun:

• Full

 

Fertilization: 

• I have not found what I consider to be reliable information about fertilization for the Wax Jambu tree.
• I currently feed it with about half the dose of fertilizer that I would give my citrus trees.
• However, based on how fast these trees are now growing, I think I might have to cut back on the fertilization.
• The soil I use at planting is pretty rich, so I am sure that is a contributing factor.

 

Temp:  

Location, location, location:

• The Wax Jambu is considered a tropical/Subtropical tree.
• Therefore, you should plant this tree in one of the warmest parts of your yard.
• Specifically, avoid planting in low lying depressions or heavy shaded areas of your yard that will collect cold air in the winter.
• I have noticed that this tree does loose about a third of its leaves in the winter, but quickly grows them back in the summer.

 

Winter Protection:

• Some have said that you need serious structural protection (such as a greenhouse) to have this tree produce fruit in Southern California.
• However, that has not my experience; I have lots of fruit with no major structural protection provided.
• My trees are planted out in the open.
• However, I do try to cover my tropical/subtropical plants with a frost cloth/blanket when we have a below freezing  cold spell in the winter.
• The key to using this frost cloth it to make sure it goes all the way to the ground to protect the trunk.
• I make a kindof pillow-case out of the frost cloth with the help of duck tape. These ‘pillow cases’ are easy to make and you can quickly throw them over to cover a tree.
• You can get frost cloth/frost blanket at various agriculture/farming stores.  However, I have seen that Amazon has some great options.  Below is a link to one option that has awesome reviews.
• Plant protection/Frost blanket.

 

USDA Plant Hardiness Zones:

• I have not seen a lot of definitive info about the exact growing zone for the Wax Jambu.
• However, I suspect the USDA Plant Hardness zone for the Wax Jambu would be around 10a and above.
• (For more information about growing zones (and figuring out your specific growing zone), see my recent article on the topic of USDA Plant Hardiness Zones)

 

Pests: 

Ants & Aphids:

• I have 4 Wax Jambu trees growing in different parts of the yard and they all seem to be a favored target of ants and the aphids they bring in.

• Overall, they only seem to attack young leaves and flower buds.
• I sometimes spray the ants & aphids off with a garden hose, which works for about a day.
• Using my citrus leaf miner spray mix of horticulture oil and spinosad works great for about a week or two… Then the spray may need to be reapplied.
  • (Note: the Wax Jambu tree does not get the citrus leafminer infection.  However, that same spray I use for leaf miners will take care of just about every unwanted sap-sucking bug in your garden).
  • (see my article on citrus leafminers for more info).

 

Prevention:

• For most of my other fruit trees, I use Tanglefoot as an organic prevention tool.
• However, Tanglefoot is more challenging to use on the Wax Jambu due to the bushy architecture of this tree.
• The reason is that TangleFoot is typically applied around the trunk of a tree to prevent unwanted guests from crawling up.
• This is great for most fruit trees.  However, the Wax Jambu is more of a big bush.  Therefore, there are a lot of branches hanging down that act like a bug-bridge around the TangleFoot barrier.

• Note:  If you do use Tangle Foot (which is a great product), don’t apply the Tanglefoot directly to the bark because the bark can be easily damaged by direct contact.  Create a skirt of masking tape around the trunk of the tree (with the sticky-side out) or get the specific Tanglefoot guard paper wrap.  Then add the Tanglefoot goop onto that skirt/paper.

 

Birds & Squirrels:

• These pesky animals haven’t seemed to fully notice the Wax Jambu fruit yet.
• Perhaps it is so foreign to them that they haven’t figured out that this fruit could be on the main menu.

Scare tape: 

• That being said, I did notice a few bird peck marks on some of the fruit early on in the season. I suspect they were trying to figure this new offering out.
• When I noticed the evidence of those curious birds, I put up bird scare tape tied to a branch next-to the fruit,  This has been keeping the aerial and ground raiders away.

Pinwheels:

• Recently, I have also been experimenting with mylar pinwheels for the same animal-scare purpose.
• I just tie the mylar pinwheels to a nearby stake or branch and make sure they can spin freely in the wind.
• So far it has been working great too.

• I often get things like this on Amazon for a good price.  However, the current price that I found for this product on Amazon costs more than the price that I stumbled upon at Target.   Here is the Amazon link for reference.  Either way they are cheap, but I got the same exact product at Target for 99 cents each.
• Note: If you are looking around at Target (or perhaps at any other similar store), I found these mylar pinwheels in the kids toy section of the store.  Unfortunately, I suspect that this product is a seasonal thing.
• Is it worth the cost of gas for a special trip to Target to save a bit on price?…. Well, probably not.  However, if you are going to a store like Target anyways, it is worth checking out.

Fruit Use:

• The Wax Jambu is a refreshing treat just picked fresh off the tree.
• In its native growing region, the fruit is also frequently used in salads and lightly sautéed dishes.
• Some parts of the tropics also pickle the fruit.

Misc:

Other names for this fruit:

• This fruit has a lot of names… many of them are some version of apple.  Example, Jambu ample, wax apple, love apple, java apple, royal apple, Jamaican apple, water apple, mountain apple, cloud apple, rose apple.
• Due to the shape, the fruit is also known as bell fruit or bellfruit.

• There are many regional names for this fruit.
  • Jambu air (Indonesian and Malay)
  • Champoo (a transliteration of the Thai name)
  • lembu or lian-woo (from the native Taiwanese name)
  • Makopa  (Philippines).
  • Jaamrool (Bengali language)

Native:

• The plant is native to South East Asia (specifically the Greater Sunda Islands, Malay Peninsula and the Andaman and Nicobar Islands)