Male and Female Lakshmi Taru Trees: Why Much of Your Block May Never Fruit

Simarouba glauca is polygamodioecious — male, female and mixed trees are separate plants, and only female trees crop. How to tell them apart, why grafted material matters, and how to fix a male tree.

The short answer

Simarouba glauca is polygamodioecious. A seedling grows into one of three kinds of tree, and they are separate plants:

Female (pistillate) — bears fruit. Roughly 40–50% of a seedling population.
Mixed (andromonoecious) — mostly male flowers with a few bisexual ones. Sets little. Roughly 40–50%.
Male (staminate) — pollen only, never fruit. Around 5%.

You cannot tell which you have until the tree flowers, in year four to six. Plant an acre of unsexed seedlings and, on those proportions, something close to half of it will never give you a crop worth harvesting. You find this out five years in.

This is the most important fact about growing Lakshmi Taru, and it is missing from almost every Indian listing selling the plant.

"Dioecious" is the word you'll see, and it isn't quite right

Most Indian material — including, until we checked, this page — calls the species simply dioecious, meaning male and female trees are separate. The botany is a step more complicated, and the difference matters commercially.

Polygamodioecious means the population carries male, female and mixed trees. The mixed ones are the trap: an andromonoecious tree flowers heavily, looks productive, and sets very little fruit, because most of its flowers are functionally male. A grower watching a block flower in year five can easily believe it is about to crop, and be wrong.

Purely female trees are obligate cross-pollinators — they carry no pollen of their own and cannot self. They need pollen from somewhere, which is why you deliberately keep some non-female trees rather than rogueing them all out.

Why this costs people so much money

A farmer buys 160 cheap seedlings and plants an acre. Pits, manure, fencing, four summers of irrigation, four years of weeding. Somewhere in year four or five the trees flower for the first time — and only then does the composition of the block become visible.

If it came out male-and-mixed heavy, nothing gives back the four years. The options are top-working to female scion, which costs money and another two to three years, or starting again.

The seedlings saved a few thousand rupees. The mistake cost four years and the whole establishment cost.

Telling them apart

Before flowering: you cannot — not in any way available to you. There is no reliable way to sex a Simarouba seedling from its leaves, vigour or form. Anyone who claims otherwise by eye is guessing.

One honest caveat: this is an active research area. A DNA marker linked to sex in Simarouba glauca was reported in the Journal of Horticultural Science and Biotechnology in 2009, and work on biochemical and molecular markers for the species' polygamodioecy has continued. So the problem is not scientifically unsolvable — it is simply that no routine, affordable sexing service exists for a farmer buying saplings in India today. If that changes, it will change this crop. Until it does, a graft from a known female mother tree is the only practical answer.

At flowering, the difference becomes readable. Flowering is annual, beginning in December and continuing into February.

	Male (staminate)	Mixed (andromonoecious)	Female (pistillate)
Flowers	Pollen-bearing only	Mostly male, a few bisexual	Pistillate, no pollen
Fruit set	Never	Light and unreliable	The crop
Share of a seedling block	~5%	~40–50%	~40–50%
Worth keeping?	A few, for pollen	A few, for pollen	All of them

The practical test remains simple: a tree that flowers freely year after year and carries no fruit by April is not a female tree. Fruit matures from March into April, so that is when you walk the block and mark it.

What to buy instead

Grafted planting material from a known female mother tree. The scion carries the sex of the tree it came from, so a graft off a proven pistillate tree is female. You know what you planted on the day you plant it, instead of finding out in year five.

Grafts cost several times what seedlings cost. In a crop with a four-to-six year verification lag, that premium is the cheapest insurance available.

Questions to ask any seller, and what the answers tell you:

Is this grafted or seedling? — evasion means seedling.
Which mother tree is the scion from, and has it fruited? — a real nursery can answer.
Can you supply pollinator trees too? — a seller who asks "why would you want those?" does not understand the crop.
What ratio do you recommend? — see below. A seller with no view, or one who quotes a single number as settled fact, has not looked into it.

You still need pollen

A block of nothing but female trees sets poorly or not at all, because pistillate trees carry no pollen and cannot self-pollinate. The tree is insect-pollinated, largely by bees.

How many pollinators is genuinely unsettled. Tamil Nadu Agricultural University's material recommends a male:female ratio of 1:6. A study of the species' polygamodioecy points to 1:20. That is a threefold difference, and nobody quoting either number at you usually mentions the other.

What to do with that: err toward more pollinators if your block is isolated or there is no other Simarouba nearby, and toward fewer if there are established trees in the area. Every tree given over to pollen is a tree not giving fruit — but a block that sets nothing is worse than one carrying a few extra males.

Distribute them through the block rather than clustering them at one edge. Pollination is by bees.

We list pollinator saplings as a product for this reason. Almost nobody else in India does, and the omission tells you most of what you need to know about how well a seller understands what they are selling.

If you already have a block of unsexed seedlings

Not a disaster, but act deliberately.

Wait for flowering, then walk the block in March–April — when fruit is visible, not just flowers. Mark every tree: fruiting, flowering-but-barren, not yet flowered. Paint or tag them properly; you will rely on this record.
Count what you have. Expect roughly half to be worth keeping as croppers.
Keep a handful of non-female trees for pollen, spread through the block — on the order of one in twenty.
Top-work the surplus. Cut back and graft female scion onto the established root system. You keep four years of root growth, which is the expensive part, and return to bearing faster than replanting.
Replant only the weak trees, this time with grafted female material.

Top-working is ordinary nursery work, but it is skilled. If you have not done it, get someone who has.

Frequently asked questions

Why is my Lakshmi Taru tree not fruiting? The usual reasons, in order: it is a male or mixed tree and will never crop properly; it is not yet old enough, as fruiting starts in year four to six; or there is no pollen source near enough to pollinate it.

Can you tell if a Lakshmi Taru seedling is male or female? Not before it flowers, which takes four to six years. This is why grafted material from a known female mother tree is worth the premium.

Is Simarouba glauca dioecious? It is polygamodioecious — the population contains male, female and mixed (andromonoecious) trees rather than only two sexes. Only the female trees crop reliably.

How many pollinator trees do I need? Guidance ranges from one in six (TNAU) to one in twenty (from research on the species' polygamodioecy). Lean toward more if your block is isolated, fewer if other Simarouba trees grow nearby, and spread them through the block rather than clustering them.

Can a male Simarouba tree be converted to female? Effectively yes, by top-working: cutting it back and grafting female scion onto the existing rootstock. You keep the established roots and return to bearing faster than by replanting.

Are grafted Lakshmi Taru plants worth the extra cost? In our view yes, and it is not close. The alternative is discovering the composition of your block in year five with no way to recover the intervening time.

Sources: sexual system and population proportions from published work on polygamodioecy in Simarouba glauca*; flowering and fruiting months and fruit description from* eFlora of India. See docs/SOURCES.md.