Lamb Hass plantings continue to expand in California, and the variety is rapidly approaching the number two position after Hass in terms of acreage and volume. Mid-season estimates of the Lamb Hass crop put the total fruit volume at about 7 million pounds with around 1,500 bearing acres.
Lamb Hass was selected from the progeny of open pollinated Gwen seeds and was released from the University of California Breeding Program in 1996. Recent interest in the variety can be attributed to several factors. Lamb Hass is precocious, often producing a significant crop in the second year of planting and has a significantly higher yield potential than Hass over the life of the orchard. The variety matures later than Hass, and in most areas reaches peak eating maturity in mid to late summer. Fruit from some areas is available on the U.S. domestic market when the supply of good quality Hass is limited and so may fetch a premium.
Lamb Hass has some distinct characteristics that make it gratifying to grow. It has an upright habit making it more suited to high density planting; the fruit is borne inside the canopy protected from sun; and the branches are elastic -- bending, rather than breaking under characteristic heavy fruit loads or during winds. The tree is also relatively resistant to infestations of persea mite.
But the variety is not without problems. Fruit from young immature trees are prone to exhibit a number of undesirable characteristics including early on-tree darkening of the skin (to a deep black color) along with fruit drop, often before the fruit reaches legal maturity. Also, fruit from young trees tends to be too large and may reach large size long before reaching legal maturity. These characteristics may alarm new Lamb Hass growers and in the ensuing panic they may demand that their handler accept the fruit before it has reached acceptable minimum maturity. Lessons learned over the last few years show that these actions damage the reputation of the variety amongst retail buyers and harm every Lamb Hass grower.
Fruit from young Lamb Hass trees can be slightly fibrous (stringy) when ripe. This is especially true when the fruit are picked prior to reaching minimum maturity. As the fruit matures on the tree, the tendency for fibrousness declines and usually by July or August the fruit will ripen with minimal fibers.
Lastly, fruit allowed to reach full maturity on young trees may split before harvest, particularly larger fruit, as the skin becomes inelastic and brittle.
While the problems associated with young trees described above may be the cause of some alarm amongst new Lamb Hass growers, experience has shown that most of these symptoms of juvenility will disappear as the trees mature.
Lamb Hass remains a viable option for California avocado growers who want to diversify their operations and compete in the traditionally late U.S. market. Remember, the Hass Avocado Board collects assessments on varieties "indistinguishable" from Hass -- Lamb Hass is considered such a variety and effective Nov. 1, 2003 an assessment rate of 0.025 cents per pound is levied on all Lamb Hass avocados marketed or imported to the fresh market in the United States.