Avocado trees are broad-leaved evergreens in warm U.S. Department of Agriculture hardiness zones 8 through 11. They grow to a mature height of 30 to 60 feet and produce avocado fruit. All avocado trees are either Type A or Type B. This has to do with their blooming habits. They are also Guatemalan, Mexican, West Indian or a hybrid combination thereof.
Type A and B
Avocado trees that are Type A produce flowers that open in the morning, close back up and then open again the next afternoon to complete the pollination cycle. When the flowers open on the first morning, they are female. The flowers open the next afternoon or evening as males to disperse their pollen. Avocado trees that are Type B produce flowers that open in the afternoon or evening as female flowers, close back up and then open again the next morning as male flowers. Planting Type A and B avocado varieties together can improve pollination success rates.
Guatemalan avocado trees are native to the tropical highlands. They can withstand temperatures to 28 degrees Fahrenheit. These trees bloom in March and April. The resulting fruit matures from September to January, weighing between 1/2 and 5 lbs. with a medium to high oil content. Gwen, Meya and Reed are Guatemalan varieties with Type A blooming habits. Kampong and Tonnage have a Type B blooming habit.
Mexican avocado trees are also native to the tropical highlands and can withstand temperatures to 26 degrees Fahrenheit. They bloom in January and February. The fruit ripens from June to October and weighs less than 1 lb. This type of avocado also has a medium to high oil content. The foliage has an anise or licorice fragrance. Mexicola and Mexicola Grande are Type A blooming varieties. Shepard and Winter Mexican are Type B varieties.
West Indian avocado trees are native to the tropical lowlands. They can withstand temperatures to 30 degrees Fahrenheit and bloom in February and March. The resulting fruit matures from May to September and weighs between 1 and 5 lbs. with low oil content. Dupuis and Simmonds are Type A blooming varieties. Hardee and Pollock are Type B varieties.
The Fuerte variety is a Mexican x Guatemalan hybrid with a Type B blooming habit. Lula is a Guatemalan x West Indian hybrid that has a Type A blooming habit. Marcus and Monroe are Guatemalan x West Indian hybrids with Type B blooming habits.