400 years is possible. 30-40 years is typical.
Evergreen. Some leaves start dropping during flowering,
and on into warmer months, and are quickly replaced.
Usually rapid. A few cultivars are slow.
30-40' high and 25-35' wide is typical. Some
can reach 80' in a suitable climate. Dwarf cultivars are available.
Yellow-green, small, clustered. While flowers have both male and female parts,
avocado cultivars fall into two flowering types called A and B. In the morning, type A
are open as females, and type B are open as males. In the afternoon, type A are open as
males and type B are open as females. This unusual flowering behavior increases the chance
of cross pollination and genetic diversity.
There is an overlap on the same tree between male and female openings, however,
especially when previous night temperatures were below 70°F, increasing the chance
of bees pollinating flowers within the same tree. Usually no fruit set occurs below 60°F.
Late winter or spring. Avocado trees can display "alternate bearing" with a heavy
crop in one year followed by a light crop the following year. Some cultivars are more
prone to this than others.
Yes. Most trees get better at producing fruit with age and
residential gardeners do not need a second tree. For commercial growers,
two trees, one of flowering type A, the other B, can provide a 20-95% increase
in fruit production depending on distance between the trees and cultivar used.
Years before fruiting:
Grafted rootstock 3-4, grown from seed 8-20.
Egg-shaped, pear-shaped, or spherical. Yellow-green
to purple-black skin can be smooth or pebbly, and range from thin to thick.
Flesh is light green to yellow. The single seed varies from small to large.
Since the tree has an extended flowering period, it will have fruits of
varying degrees of maturity. Weight range 3-40 ounces depending on cultivar.
Months for fruit to ripen:
6-18 depending on cultivar. Avocados
attain maturity on the tree but can only ripen after reaching maturity and
after dropping or being picked off the tree. For many cultivars,
the fruit reach full size before they mature, so the only reliable
indicator of maturity is when the fruit falls from the tree, making
a tarp under the tree worthwhile. One harvesting problem is picking the
fruit too soon, before maturity, and then the fruit never ripens.
Storage after harvest:
Mature avocados can take 4-5 days to ripen at
room temperature. To speed ripening, place in a paper bag with
apples or bananas. Once ripe, the only storage is to cut them open, mash
the ripe flesh in a bowl, and add lemon juice. This will keep for a day
refrigerated or longer frozen.
Dark green, glossy, oval, remain on tree for 2-3 years. Some leaf drop
when flowering is normal and may continue into warmer weather. Mexican cultivars
have an anise aroma. Guatemalan and West Indian leaves, without an anise aroma,
are mildly toxic.
No thorns. The thin green skin on the trunk is prone to sunburn, especially
during the first three years. This tree should not be pruned, particularly lower
branches, so that its leaves can shield its trunk from direct sun. After three
years, the trunk skin gradually hardens into a thicker, bark-like covering.
Tap root plus shallow feeder roots no deeper than 6-8". Most trees are grafted
onto a hardy rootstock.
The 'Lula' rootstock, which originated in Florida, is salt tolerant, does well
in alkaline soil, is cold hardy to at least 28°F, and is vigorous and heavy bearing
as a tree. This is a preferred rootstock in Texas and Arizona.
The 'Dusa' rootstock is used in California because of its disease resistance,
high yield and salt tolerance. It is also known to be hardy in Arizona.
In climates with winter freezes, the graft union should be placed low on the
rootstock to make it easy to protect with soil or mulch.
Cultivars of Note:
'Bacon' - Hardy to 25°F, tree grows 20' tall, medium sized fruit, large
seed, green skin, low-oil watery flavor, fruit tends to spoil quickly when ripe,
'Lila' / 'Opal' Hardy to 18°F, possibly lower,
medium sized fruit, green skin, average flavor, average and inconsistent production.
Slowly grows about 10" a year, reaching 20-30' tall. Easy to grow in a container for
those wanting a small outdoor tree. Will need 50% all day shade protection in the summer
for up to 10 years. Sold by Texas nurseries.
'Mexicola' - Hardy to 18°F, very heat tolerant, tree grows to 25' tall
and 20' wide, high yield, small fruit with large seed, thin edible skin, very good
'Stewart' - Hardy to 18°F, tree grows to 30' tall and as wide, low yield,
small to medium fruit, medium seed, excellent flavor. This might the best tree for those
not wanting an over-supply of avocados when the tree becomes large.
'Wurtz' / 'Little Cado' - Hardy to 25°F, slow growing dwarf tree 8-15' tall,
weeping growth habit, small to medium fruit with small seeds, medium-thick green skin,
good flavor, consistent moderate yield. Best avocado to grow in a container on wheels
and run inside when freezes are predicted.
'Zutano' - Hardy to 25°F, tree grows 30-40' tall and wide, grown primarily
as a pollenizer for 'Hass' in California. Medium sized, glossy green skin, fibrous
fruit with large seeds, low-oil watery flavor, high yield, poor disease resistance
leading to short life span.
Attracts bees. Fruit attracts mammals.
Toxic / Danger:
All parts mildly poisonous to animals. Unripe fruit mildly poisonous.
Leaves of Mexican varieties and ripe fruit of all varieties are not dangerous to humans
except in the case of rare allergies.
Cultivation and Uses
USDA hardiness zones:
8b-11 for a few cultivars, 9b-11 otherwise.
Sunset climate zones:
16-17, 19, 21, 23-24.
A few cultivars, listed above, tolerate temperatures over
Full sun when the tree is over 8' tall and in the ground three years.
Yes, after three years in ground.
Water after becoming established:
Deep water weekly when fruiting, monthly
at other times, especially during drought. Use
. Soil should be dry 9" deep before watering.
Root rot and other diseases occur in moist soil.
Very well drained, high in organic content, low salinity, pH tolerance
varies by rootstock.
Use organic compost, worm castings, or fish poop. Chemical-based
fertilizer use should be avoided so as to keep soil salinity low, a problem with
desert soils. In any case, chemical-based fertilizers must not be used the first
year in the ground. A composted foliar spray can also be employed.
Use up to 1' of mulch. Keep mulch 8" away from trunk in moderate
to high rainfall regions. Avocado leaves that have been dropped by the tree
make the best mulch. Use leaves, pine needles or shredded bark when avocado leaves
are not available.
Test the proposed location for the tree by digging a hole,
filling it with two gallons of water, and checking that the water has
drained completely within one hour. If not, place the hole on top of a large
mound of soil at least two feet above ground level.
First three years care:
During the hottest months of the summer, provide
afternoon shade until the plant is over 8' tall. For some cultivars, all day
50% shade cloth may be necessary in the hottest months of the year.
A cloth sheet may need to be draped over the entire tree and
down to the ground when nights are below freezing until the plant is 8' tall.
Water the tree every two to three days, unless freezing temperatures are near,
using basin irrigation
, to establish a strong
During the cold winter months, build a temporary block wall on the north side of
the newly planted tree, about 3' away from the tree in the first year, to keep it warm
in winter. Use stacked blocks without mortar, about 6' long, 3-4' high and 1' wide.
The wall should be white on the north side and dark on the south side facing the tree.
As the tree grows, move the wall back to avoid branches and roots. The wall, which
will radiate heat during winter nights, may be removed when the tree is more than 8' tall.
Never prune branches, especially lower branches, except to keep them
barely off the ground. The leaves must protect the trunk from direct sun top
to bottom. Fruit develops on new growth.
Pruning can be used to dampen alternate bearing. In the fall after a light bearing
year, remove 50-75% of new growth that would result in new flower clusters. This
will lower fruit set in the following year.
Fruit if not harvested. Fallen avocado leaves must not be discarded, but
used as mulch under the tree, directly on the soil.
Cuttings grafted onto rootstock. Seeds are only viable for
one month after being removed from their fruit and often do not grow true.
Ornamental, edible fruit.