Can You Grow an Avocado in Zone 8?
Avocados fall into three categories: Guatemalan, Mexican, and West Indian. Each group is named after the region where the variety originated. Today, there are new hybrid varieties available that have been bred to be more disease resistant or more cold hardy. Depending upon the category, avocados can be grown in USDA zones 8 to 11. The West Indian is the least cold tolerant, hardy only to 33 degrees F. (0.5 C.). The Guatemalan can survive temperatures down to 30 degrees F. (-1 C.), making neither of them a great choice for a zone 8 avocado tree. A better choice when growing avocado trees in zone 8 is the Mexican avocado, which can tolerate temps down to 19 or 20 degrees F. (-7 C.). Keep in mind that the range of minimum temperatures for zone 8 is between 10 and 20 degrees F. (-12 to -7 C.) so growing any type of avocado outside is a risky undertaking.
Avocado Plants for Zone 8
Due to its cold tolerance, the Mexican avocado is classified as a subtropical tree. There are several types of Mexican avocado plants more suitable for zone 8.
The Mexicola Grande is a Mexican type of avocado that can take colder temperatures without injury, but it does like a dry climate. The Brogdon is another type of hybrid Mexican avocado. This avocado is cold resistant and tolerates a rainier climate. Another hybrid is the Duke.
All of these only tolerate temperatures down to 20 degrees F. (-7 C.). Choosing a zone 8 avocado tree depends upon your microclimate, the amount of rain your area receives, the level of humidity as well as the temperature. Age also has to do with how well a tree survives a cold snap; older trees weather it much better than young trees.
Growing Avocado Trees in Zone 8
Avocado trees need to be planted in a warm area with full sun for at least six to eight hours a day. Although they will grow in part shade, the plant will produce little to no fruit. Soil may be of almost any type but with a pH of 6 to 7 and well-draining. Since they are semi-tropical, water them deeply and frequently. Allow the soil to dry out between watering so the roots don’t rot. Be aware that if you live in an area of high rainfall or the tree is planted in poorly draining soil, avocados are highly susceptible to Phytophthora fungi. Space additional trees 20 feet apart (6 m.) and situate them in an area that is sheltered from high winds which can break limbs. Make sure you plant them on the south face of a building or underneath an overhead canopy to protect them from cool temperatures. When temperatures threaten to dip below 40 degrees F. (4 C.), be sure to place freeze cloth over the trees. Also, keep the area around the tree out to the drip line free of weeds which tend to hold the cold in the ground. Mulch the plant above the graft union to protect both the rootstock and the graft from the cold air. Again, each USDA zone may have many microclimates and your particular microclimate may not be suitable for growing an avocado. If you live in colder areas where freezing is a common occurrence, pot the avocado tree and bring it indoors during the winter.
