Bloom season is the most exciting for me when it comes to avocados. First, I look at the buds on the branches of trees to try to predict how many will become flowers. Then I observe the bees and flies visiting the flowers. Are there enough? Are the flowers getting pollinated? Finally, I search for green BBs, the sign that fruit has set and that next year will have a harvest. There’s so much hope.
Do you also enjoy this process? Is it new for you? I walked around to some of my trees this spring to show you what it all looks like from flower bud through to tiny green fruitlet. Have a watch:
Literature on avocado flowering
There is a lot that can be learned about avocado flowering. Here are five excellent articles that will teach you the basics, as well as take you into topics like flower types, cross-pollination, and pollinators.
1. Bob Bergh’s classic article: “The Remarkable Avocado Flower.”
2. Mary Lu Arpaia and Reuben Hofshi provide a glossary of terms and a list of published literature in their article: “The Avocado Flower and the Pollination-Fruitset Process: Ideas from a California Perspective.”
3. Read only the introduction of this paper for a summary of the seminal discoveries and discussions about avocado flowering over the last century: “Finding the best polliniser for ‘Hass’ avocado and the effect of honeybees as pollinators” by Bezuidenhout, du Toit, Robbertse, et al.
4. Nirody was the first to write about avocado varieties having male or female flowers at different times, and he suggested pairing trees for pollination, all in his Master’s degree thesis written exactly one hundred years ago: “Investigations in Avocado Breeding.”
5. Stout was the first to classify avocado varieties as “A” or “B” according to their flowering behavior in his paper, “A Study in Cross-Pollination of Avocados in Southern California.”
Video presentations on avocado flowering
Here you can view two comprehensive presentations by Mary Lu Arpaia, of the University of California, and Reuben Hofshi, creator of Avocadosource, about avocado flowering and pollination.
Yard Posts related to avocado flowering
You might like to check out these other posts I’ve written that are related to avocado flowering and the fruit set and fruit drop stages just after flowering:
“What are the best avocado pollination conditions?”
“Mobile avocado pollenizer tree”
“Should you remove avocados from a small tree?”
“Avocado fruit drop: Why? When? How many?”
Enjoy the bloom and fruitset season. I hope you are starting to see these:
All of my Yard Posts are listed HERE
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Hi Greg. please tell me whether these trees are A or B:
fuerte
hass
Gem. Thanks Greg. your posts are great
Hi Tom,
Fuerte: B, Hass: A, GEM: A. Thanks!
I’ve been thinking of writing a post that is just a list of all avocado varieties whose flower types I know firsthand. I should do that.
This post is very helpful to me in determining the flowering stages. The 2 trees I have are about 45 days apart in flowering. The Ettinger fruitlets/fruit sets appear at bit larger as your photo above, while the mystery tree (leaves are anise scented, pretty sure it flowering pattern is A) is in a very sparse bb stage (it had a huge crop last year). Is there any stage of flowering that will help me determine the variety? Thank you.
Hi Kathryn,
Figuring out the flower type of your tree will help narrow the variety options, and it’s not difficult to figure out the flower type once you know what to look for. I made a video about this but I think I never published it. I should do that and write a post too.
Otherwise, if you are very familiar with avocado flowers you can even spot differences in the physical appearance and smell between varieties. But very few people in the world are so familiar.
To help determine the variety of a tree, it’s best to be able to see everything from flower to fruit to leaf to canopy shape, even to the color of new stems since only some avocado varieties have red flecks on their new stems.
I look forward to your flowering video post. Until then, there are some red flecks on the new stems. I use to think the flowers were A type due to their opening and closing pattern. But then I noticed they would sometimes open and close in snyc with the B Ettinger. Your post on Fuerte characteristics mention cucumbers, a slanted bottom, and that they were planted often with Ettinger. The mystery tree sometimes hits all these notes, including the nutty flavor. This just-past crop was the first time I have ever seen the (tiny) cukes. So I’m calling it as Fuerte for now….unless you think otherwise. Thanks for all your help!
Hi…I planted a Haas avocado tree from nursery 5 years ago. Tree looks good and getting new leaves but has never flowered. Any suggestions?
My two-year old Sir Prize is very happy this season when we took it out of the half wine barrel and mound it in the ground. When should the Sir Prize begin showing developing flowers? I am looking forward to watching the tree go through these stages.
Hi Laura,
This depends a bit on your climate and the age of the tree and the weather in a given year, but Sir-Prize for my area in San Diego County generally start pushing flower buds in January. (They’re all finished or near finished blooming here in mid-May.)
This year I experimented with spraying a weak urea solution on the cauliflower stage. The additional nitrogen has been shown to increase fruit size in the research of Carol Lovatt. She has a video online at https://www.youtube.com/watch?v=oALcUac5YVM&t=5s and addresses urea at 25:45.
I have a wurtz that doesn’t change from male to female , my second one does , familiar with the two stages of the flower but this one puzzle me , is this possible ? Thanks.
That’s weird, Jose. Sounds like the behavior of a B type avocado tree. Could it be mislabeled, or have you gotten fruit from the tree and know it’s Wurtz?
Greg, I enjoy your posts so much especially about the citrus trees and the avocado. I live below Selma AL and my trees are in pots. I take them in during the winter and they don’t like it 😏. My avocado tree was doing great until I moved it in then it lost its leaves but started blooming like crazy. At this point I’m just praying for it not to die and the leaves come back.
I have a Fuerte, a Gem, and a Hass all blooming alongside Bermuda buttercups (weeds) and broccoli (not a weed but I let them go to blossom). I figure my avocados are like the snack bar next to the main attractions that have attracted bees for weeks. Not everyone knows this: Theaters break even on movie rentals, profit is all from the snack bar.
Greg I have an approximately 10 year old avo tree grown from a pit (my friend planted it so no other info) that is reasonably healthy- about 10’ tall- that is starting to flowe now. Any suggestions on how to promote fruiting? I am 1.5 miles from the coast in Cardiff. Thanks for your time and help Dave
I have a fuerte that has new fruitset and baby avocados growing. How much and how often should I water?
https://gregalder.com/yardposts/how-much-and-how-often-to-water-avocado-trees-in-california/
Hello Greg,
I am a recently retired San Diego County Park Ranger and thought I would take up a new hobby of trying to successfully grow some Avocado Trees. My first attempts failed miserably (I did virtually everything wrong, based on subsequent research). I have since read many, if not all, of your posts and have tried to implement as much as possible. I purchased two trees (a Haas and a Fuerte, both 15 gal from Maddock Ranch Nursery in Fallbrook). They are wonderful people! The trees were planted on March 19, 2024. I’m keeping a weekly diary, using the “Yard Posts” calendar, put together by you, that I find highly informative and beneficial. I keep track of growth; new leafs, flowering, any damage and misc. observations along with weather conditions. The trees were planted approx. 12’ apart and on mounds. The drainage is good and I installed a drip system. Should I be expecting substantial growth now or does it take longer to see growth? Both trees are the same height as when planted 69” and 71” The Haas is showing substantial new leaf development and a good amount of flowering. The Fuerte appears to be virtually the same as the day it was planted, no flowering and many small buds but no new leaves appearing. Should I be worried or do I need more patience? Thanks, for all of your wonderful posts!
Hi Ken,
I love the attention to detail. Now is the time of year when the trees begin growing after a winter sleep, but not all are on the same schedule. Even among trees of the same variety there will be variation. It’s possible that your Fuerte started growing earlier than the Hass and is now pausing before its second flush of growth for the year. It’s also possible that it’s about to start any day. Avocado trees usually have two or three periods of growth each year.
Thanks for the kind words about my posts here!
Hi Greg I live in east of England about 70 miles from London. I have been growing an avocado for about eight maybe nine years it stands in a tub about 3‘ x 2‘ deep( it’s on wheels ) it’s about 6 foot high and quite bushy. I feed it blood fish and bone mixture and each year we have a lot of growth. it lives in a greenhouse through the winter and move it out side for spring summer and autumn. Sadly, there’s no sign of flowering.
Hi Tony,
Great to hear that your tree sounds very healthy, but seedling avocados are a long-term commitment when it comes to flowering. You just never know if they’re going to flower after a couple years or ten years (or more!). If your tree was grown from the seed of a Hass though, there is a good chance that it will flower soon.