By: Angela Chandler, www.thegardenacademy.com , www.facebook.com/pages/TheGardenAcademy/118766921485456

Avocados have a somewhat complicated pollination cycle. They are slightly confused about their sexuality! Their flowers are perfect (male & female parts), and so should be self-fruitful, right? 

Two complications: 

1. the flowers have a 2-day life cycle in which the male and female parts are not accessible at the same time. 
2. there are Type A and Type B trees, and their sexual cycles are different. 

A simplified explanation: In Type A, flowers open as females during the morning of Day One, close, then open as males the afternoon of Day Two. In Type B, flowers open as females in the afternoon of Day One, close, then open as males the morning of Day Two. 

Type A females would benefit from the Type B males every morning and Type B females would benefit from Type A males in the afternoon. 

Since not all of the flowers are the same ages, there should be some females open at the same time as some males on the same tree regardless of type. However, females are only receptive to pollen for about 2 – 4 hours, which narrows the pollination window. 

A lot of texts stop there, and leave the impression that in a perfect situation, one would plant a Type A and a Type B for the best pollination and would have little chance of pollination otherwise. 

But temperature changes things. The seemingly strict rule of sexual cycles only applies in tropical locations where temperatures are consistently above 70 degrees. In our climate, where cool temperatures can persist during the bloom time, the female and male cycles can become irregular, creating MORE of an opportunity for overlap. This results in having enough receptive females and pollen-shedding males open at the same time for pollination, regardless of type. 

Of course, a mature avocado may present hundreds of thousands of blooms, where only a few hundred will be successfully pollinated and produce fruit, but that is what we are looking for; 200 – 400 perfect, organically grown, creamy avocado fruits. 

For the record, Haas is a Type A. Mexicola and Mexicola Grande are also Type A. I have had almost no luck finding out the type of the “found” Mexican varieties. But since we benefit from the irregularity of the sexual cycles due to the avocados blooming during our cool winters, we should still have good crops from them, even if we plant only one type. 

The problem with a seedling grown Haas is that it may be 10 – 15 years from seed before it will bloom and produce. It is also not a terribly hardy cultivar. So, all things considered, if we don’t have a harsh winter for the next 5 or 10 years, she may have fruits from her Haas. In the meantime, I would plant one of the hardy Mexican varieties as an insurance policy. 

If you have more questions, email Angela at: achandler@thegardenacademy.com