Avocado Trees (Persea americana)
As a member of the Laurel plant family (Lauraceae), Avocado trees are botanical cousins to the plants that produce cinnamon and bay leaves. Not surprisingly, Avocado trees are prized for more than their bark (cinnamon) or leaves (bay laurel). The luscious fruit from the Avocado tree, which is actually a large one-seed berry, is the primary ingredient in guacamole. These fast-growing evergreen trees can grow 3 feet in a single season, reaching heights of 30-60 feet with a 20-30 feet spread, although some varieties and cultivars are only half this size. Avocado flowers, from which the fruits form, are unusual among many fruiting plants; in fact, trees are classified based on the type of flowers it bears -- Type A or Type B. The flowers open as female at a certain time one day, then close and reopen as male at a certain time the next day. This alternate opening and closing mechanism can make pollination tricky, but all you have to do is plant two different types of Avocado trees, which allows for successful cross-pollination. Generally, Avocado trees are cold-hardy perennials in USDA plant hardiness zones 10-12, although there are cold-hardy varieties that grow in zones 9-11.
By growing creamy, buttery-tasting avocadoes, you’ll have your own backyard source of vitamins, minerals and other healthy nutrients. Avocadoes provide “good fats,” which help decrease cholesterol levels and reduce the risk of heart disease. Fiber-rich avocadoes are also packed with anti-oxidants, such as vitamin E, and are an excellent source of potassium.
As a landscape specimen, Avocado trees provide shade underneath their wide rounded or umbrella-shaped canopy. You can also grow Avocado trees in containers, both inside as well as outdoors. The containers will limit the size of your tree to keep it to a manageable size. If you live in a climate outside an Avocado tree’s hardiness range, you can bring in your potted Avocado for the winter and set it outside again when temperatures warm in spring.
Hint: Although starting an Avocado plant from the seed found inside a grocery-store fruit is a fun and easy gardening project, the resulting tree may never bear fruit. If it does, it will likely not be like the avocado you enjoyed from the store; plus, it will take up to 7 years to produce avocadoes. This is why we offer grafted plants.
- Full sun is what an Avocado tree needs for healthy growth and maximum fruit set -- at least 6 hours daily.
- Avocado trees must have well-draining soil, because their roots will rot on waterlogged sites.
- Slightly acidic to slightly alkaline soils are best for Avocado trees.
- Dig a hole only as deep as the root ball and about twice as wide, and backfill the hole only with the soil that you removed -- don’t fill in with potting mix or bagged topsoil.
- Water your newly transplanted tree thoroughly, and keep the soil moist but not soggy so the roots don’t dry out while the plant becomes established on site.
- If you plant during a windy time of year, you can stake your young Avocado tree; otherwise it should be okay. Remove the stake once the tree’s roots have taken hold.
- Water. Water your Avocado tree deeply instead of making light sprinklings. Let the soil dry slightly before watering deeply again. In hot weather, when your Avocado tree is fruiting, you may need to water it more than once a week if natural rainfall isn’t sufficient.
- Fertilizer. A rule of thumb for fertilizing your Avocado tree is to apply ½ to 1 pound of nitrogen each year. Add other nutrients based on soil-test recommendations.
- Pruning. If you want to reduce the height of your Avocado tree, don’t cut off all the limbs at one time, because this will drastically limit fruit production. Instead, each year cut back the tallest branch until the overall shape and size of your tree is what you want.
- Harvesting. Avocadoes don’t ripen on the tree, so you’ll want to pick them when they are fully formed and let them soften at room temperature for several days.