Our experience here in Australia is that the Acacias, which have the common name of wattle, only produce pollen and no appreciable amounts of nectar. The protein value of some of the Acacias is quite good being as high as 30% crude protein. I have not worked areas where Acacia longifolia grows in large numbers so am not familar with its traits. I have seen it but only in small numbers. At present I have bees in areas where some Acacias, namely A. fimbriata and A. leiocalyx are flowering. They are producing pollen and the bees are coming out of winter quite well. When the Acacias flower, if the air is not very moist, the bees tend not to collect the pollen as it is too dry. Also, the propolis from the Acacias is usually quite distinctive and can be easily recognized. Acacias tend to "bleed" if damaged in any way and are susceptible to borer attack. Acacias, with a couple of exceptions, only live for a maximum of 10 years. They are regarded as "pioneer" species. Hope this helps. Trevor Weatherhead AUSTRALIA