There are no true dwarf avocado trees. The variety ‘Wurtz’ also called ‘Littlecado’ or “Minicado’ is somewhat smaller than other varieties and is often sold as a dwarf avocado. Its branches are pendulous and the tree can grow 8-12 feet tall.
Avocado trees in small nursery containers usually begin to flower three to five years after they are planted. Most avocado varieties are self-fruitful and do not need another variety for cross pollination. Another variety may be needed for cross pollination with the variety ‘Gwen’ and also with ‘Fuerte’ when it is grown near the coast.
Some environmental conditions can interfere with fruit set. Avocado flowers are pollinated by honey bees and they must be present during the bloom period for fruit to develop. Flowers may be damaged by frost and insufficient soil moisture can prevent fruit from setting or cause it to drop. Soil beneath an avocado tree should not be allowed to dry completely, especially when it is flowering and setting fruit. Avocados have shallow feeder roots which are most abundant in the top 6-8 inches of soil.
It is best to water avocado trees with sprinkler irrigation about twice a week during dry weather if the trees are growing in well drained soil. Water should be applied evenly to soil under a tree from near the trunk to several feet beyond the spread of the branches. Allow fallen leaves to remain on the soil under the tree or apply a layer of woodchips or other coarse mulch to conserve moisture.
Avocados should be given a fertilizer containing nitrogen periodically from late winter through summer. Do not place fertilizer close to the trunk or apply too much at one time as this can damage roots. Scatter fertilizer evenly under a tree and water well. Manures are high in salts and should be applied sparingly if used.
By V. Lazaneo, Urban Horticulture Advisor, Emeritus, UC Cooperative Extension, August 2012