If you’re thinking about growing avocados, you’ll quickly learn about type a and b avocado trees. Understanding their distinct growth patterns is the key to getting a good harvest from your backyard. This guide will explain the simple science behind these types and show you how to use it to your advantage.
It’s all about flowering behavior. Avocado trees have a unique way of blooming to maximize cross-pollination. Each flower opens twice over two days, first as one gender and then as the other. Type A and Type B trees simply have opposite schedules. Knowing this helps you plan your garden for better fruit set.
Type A and B Avocado Trees – Distinct Growth Patterns
While “Type A” and “Type B” sound like they refer to growth shape or size, they actually describe flowering timing. This timing indirectly influences growth and fruiting success. A tree’s type determines when its flowers are receptive to pollen and when they shed it.
What Does Type A Mean?
Type A avocado varieties have flowers that open first as female in the morning. They are receptive to pollen from other trees. Then they close. The next afternoon, the same flowers open as males, shedding their pollen.
- Common Type A Varieties: Hass, Gwen, Pinkerton, Reed.
- They do their main female blooming in the morning of day one.
- Their male phase happens the afternoon of day two.
What Does Type B Mean?
Type B varieties do the opposite. Their flowers open first as female in the afternoon. After closing, they reopen the following morning as males to shed pollen.
- Common Type B Varieties: Fuerte, Bacon, Zutano, Whitsell.
- They are receptive as females in the afternoon.
- They release pollen the next morning.
Why This Pattern Matters for Pollination
The distinct growth patterns in flowering create a perfect handshake between trees. When a Type A tree is shedding pollen in the afternoon, a nearby Type B tree is receptive as a female. And vice-versa in the morning. This overlap significantly increases the chance for pollen transfer by bees and wind.
The Ideal Planting Pair
For the best fruit production, planting one Type A and one Type B tree is recommended. They don’t need to be right next to each other, but within about 50 feet is ideal for bees. Some self-pollination can occur, but yields are often much lower.
Do You Always Need Two Trees?
Not always. If you have neighbors with avocado trees, you might have a pollinator nearby without knowing it. Also, in warmer climates, the timing of the flower phases can sometimes overlap more, allowing a single tree to pollinate itself a bit better. However, for reliable crops, having both types is the safest bet.
Growth Habits Beyond Flowering
While the A/B system is for flowers, different varieties have their own growth habits. Some are tall and upright, while others are more spreading. Your climate is the biggest factor in choosing a variety for it’s growth pattern, not just it’s flower type.
Considering Your Climate
Avocados are categorized by their race: Mexican, Guatemalan, or hybrids. This affects cold hardiness.
- Mexican Types (like Bacon, Zutano) are more cold-tolerant.
- Guatemalan Types (like Hass, Reed) are more frost-sensitive.
- Always choose a variety known to thrive in your specific USDA zone.
Space and Sun Requirements
Most standard avocado trees can grow 25-35 feet tall and wide. They need full sun and well-draining soil. Dwarf varieties are available if space is limited, but they still need plenty of light. Poor drainage is a major cause of failure, as avocado roots are susceptible to rot.
Practical Planting and Care Steps
Here is a straightforward guide to getting your trees established, keeping their distinct needs in mind.
Step 1: Selection and Purchase
- Choose a Type A and Type B variety suited to your climate.
- Buy healthy, grafted trees from a reputable nursery. Seed-grown trees take many years to fruit and are unreliable.
- Consider the mature size and ensure you have enough space for both.
Step 2: Planting Your Trees
- Plant in spring after the frost danger has passed.
- Dig a hole as deep as the root ball and 2-3 times as wide.
- Place the tree so the graft union stays well above the soil line.
- Backfill with native soil, don’t amend it heavily. Water deeply to settle.
Step 3: Ongoing Care for Growth
- Watering: Water deeply but infrequently, allowing the soil to dry slightly between. Young trees need more frequent water.
- Fertilizing: Use a balanced, citrus/avocado fertilizer. Apply in late winter, early summer, and maybe early fall. Follow label instructions.
- Pruning: Prune lightly after harvest to maintain shape and remove dead wood. Avoid heavy pruning which can reduce yield.
- Mulching: Apply a coarse mulch (like wood chips) around the base, keeping it away from the trunk to prevent rot.
Troubleshooting Common Issues
Even with the right pair, problems can arise. Here’s what to watch for.
No Fruit After Several Years
This is the most common frustration. Check these points:
- Do you have both a Type A and Type B tree? If not, consider planting a partner.
- Is the tree getting at least 6 hours of direct sun?
- Are you over-fertilizing with nitrogen? This promotes leaf growth at the expense of flowers.
- Young trees need time to mature. Grafted trees typically fruit in 3-4 years.
Leaf Problems and Drop
Avocados naturally shed some leaves, especially in spring. But excessive drop can signal issues.
- Yellow leaves: Often a sign of overwatering or poor drainage. Check soil moisture.
- Brown leaf tips: Can indicate salt burn from fertilizer or water, or wind damage.
- Sudden leaf loss is often due to a change in temperature or root problem.
FAQ: Your Questions Answered
Can a Type A tree pollinate another Type A?
It’s possible but less effective. Because their female and male phases are open at the same times of day, there’s less opportunity for pollen transfer between them. Cross-pollination between Type A and Type B is far more succesful.
Is Hass avocado Type A or B?
Hass is the most popular variety and it is a Type A avocado. A good partner for it is a Type B like Bacon or Zutano.
What is the best Type B pollinator for Hass?
In cooler areas, Bacon is an excellent choice as it’s cold-hardy. In warmer climates, Whitsell or Fuerte are good options. Consider your local climate first.
Do I need two trees if I only want one?
You can try a single tree, but be prepared for potentially light or inconsistent fruiting. Planting a second tree of the opposite type is the best guarantee for a regular, heavy harvest.
How far apart can the trees be to pollinate?
Bees are the main pollinators. For effective cross-pollination, keeping trees within 50 feet is ideal. They can be further and still sometimes work, but the closer they are, the better the chance.
By paying attention to the simple but important distinction between type a and b avocado trees, you set your garden up for success. Their distinct growth patterns in flowering are a beautiful example of natural teamwork. Start with the right pair for your area, provide them with good basic care, and you’ll be well on your way to enjoying your own homegrown avocados. Remember, patience is key as these trees establish themselves.