A + B = Avocado Confusion

When we are growing up, there comes a time when we are old enough to have "that talk". I have four children. We had "that talk" a number of times. Which talk is that? The "birds and the bees". You probably know the Cole Porter tune "Let's fall in love". "Birds do it, bees do it, even educated fleas do it, let's do it, let's fall in love." How is this for irony? Birds and bees (or educated fleas, for that matter)  procreating is likely something none of us have ever seen. It used to be, you saw  all "that stuff" down on the farm. These days, not so much.
It is likely however, we have all seen plants do it. Most often with the assistance of bees, although there are a number of other insects that help out our leafy friends with procreation. One of my favorite pollinators is a moth from Madagascar that was described by Charles Darwin as the pollinator of a very cool orchid named Angraecum sesquipidale (sesquipidale means 1 1/2  feet, the length of the spur).

 The things is, "Charlie D" never observed the pollinator at work. Darwin only conjectured that this night-time scented white orchid with a ten to sixteen  inch long spur with the stigma at the bottom, must have a moth as a pollinator with a corresponding eighteen inch long proboscis. What a brilliant hypothesis! Darwin's theory was not validated until twenty-one years after his death, when the existence of the moth was documented.

I love fruit. So do you, I bet. Otherwise, why would you be reading my little "ag" blog.  Why all this talk of flowers and pollinators? Without flowers, there'd be no fruit. Without pollinators, there'd be no pollination, just lonely "wall flowers" not meeting anybody else. In flowers there are male parts, and female parts. Getting the pollen from the male part to the stigma of the female part of the flower is the work of the bees. When the pollen hits the stigma...."we have liftoff"! A marvelous thing happens. We're having a baby! Fruit is just a female flower that has been pollinated. Fruit is just a very swollen ovary.
 So to have those tasty avocados we need males and females...flowers that is. Some fruit trees are self fertile. They can pollinate themselves. Some trees need another of their species to set fruit. Avocados are classified as partially self pollinating. That said, if you have a single tree, you will get some fruit. But, if you plant two trees which pollinate each other your yields increase geometrically.

There are three types of avocados: Carribean, Mexican, and Guatemalan. No one grows Caribbean avocados here. They are pale, small, and have a bland flavor. They have a very low oil content. In the Caribbean, they are used mostly for making smoothies or shakes. Yuchhhhh! I think I'll pass.

Mexican and Guatemalan types are the ones we know and love. Please pass the guacamole! They are flavorful, large, and high in the fats that make them so smooth and tasty. Avocados are grouped into two flowering types: A and B. Sounds so simple. Even elementary. How hard can this be? Well, it is one of the toughest things to understand in all of fruit raising. Most folks wrongly assume A's are girls, and B's are boys. Maybe it should be G for girls?
 Here is how A flower types work:

(Day 1 ) Morning: Flower opens as female
(Day 1) Late morning or early afternoon: female flower closes (you're not getting in here now pollen)

(Day 2) Afternoon of the next day: SAME flower (formerly female) now opens as a male

(Day 3) flower falls off

Here is how B flower types work:

(Day 1) Afternoon: Flower opens as a female
(Day 1) Late afternoon: Female flower now closes (go away bees, don't want any pollen here)

(Day 2) Morning: SAME flower opens as male

(Day 3) flower falls off

What on earth? No wonder nobody understands A and B avocados. I can't tell the players without a program. Honestly, the beauty and complexity of the natural world amazes me. It is a wonder that we get any avocados at all! Are you confused by all this A+ B = avocados?

The bottom line is this. You need some male flowers open at the same time you have receptive female flowers that are open. The reason you only get marginal pollination with a single tree is, you have a very narrow window when you will have male and female flowers open simultaneously. The timing has to be just right...a female flower not yet closed, and a male just opening at the right time.

But, if you have a "Miss A" with female flowers looking for a morning rendezvous, "Mr B" next door is more than happy to be a pollen donor. Whereas, had "Miss A" been living alone, the male flowers on A won't open till afternoon, when the female flowers have closed for business.

Conversely, "Miss B" would love to procreate on a sunny afternoon. "Mr. A" is calling a bee to send a pollen package to "Miss B". And "ZING" went the strings of my heart. "Miss B" makes the call..."we're having a baby". Had "Miss B" been living alone, there would be no pollen from "Mr. B", because his flower opened in the morning, and is closing when "Miss B"  opens, nor any pollen from "Mr. A".

As with so many things in life, timing is everything.

How do we solve this problem? Plant at least one A and one B. If you plant one of my favorite cultivars, a Bacon (B type) avocado, a single tree is capable of pollinating up to five "A type" avocados. Pretty simple, isn't it? It doesn't need to be so hard now, does it?

A types:
Lamb Hass

B types:
Walter Hole

There is one in every group that just can't make up its mind. There is a cultivar called Wurtz (sometimes called "little cado") that is both A and B. So if you must have a single tree, this would be the one for you.


  1. I always buy avocados at different stores and can't tell what kind.. How will I tell do I look at shape... Size or what I have one tree growing inside and it is growing thick and has white flowers already.. Not even 4 in tall. There is another type next to it.. Its thin an tall

  2. I always buy avocados at different stores and can't tell what kind.. How will I tell do I look at shape... Size or what I have one tree growing inside and it is growing thick and has white flowers already.. Not even 4 in tall. There is another type next to it.. Its thin an tall


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