Rough lemon (Citronelle)
Rough lemon was the most popular rootstock during establishment of the citrus industry in WA. It is still widely used for lemons and backyard plantings of oranges and mandarins.
It produces large, vigorous, highly productive trees that are drought-tolerant. It grows well on a wide range of soils but is particularly well adapted to deep sandy soils. It does not perform well on poorly drained soils and is sensitive to saline conditions.
Fruit quality can be poor. Poor skin colour and thick skins are a potential problem. Good water and nutrient management is important to get the best out of this stock.
Rough lemon is susceptible to citrus nematodes and phytophthora root rot and is not recommended in replant situations. It is tolerant of tristeza virus, and exocortis and xyloporosis viroids.
Compatibility
Rough lemon is unsuitable for some mandarins such as Ellendale and Satsuma types. As with Volkameriana, it should not be used with mandarins like Imperial that are susceptible to internal granulation (drying), especially in areas where this is a problem.
Local experience
This stock is no longer used extensively because of its susceptibility to phytophthora. Its main use is for Eureka lemon.
Yield has been quite good in a Newhall navel rootstock demonstration block planted at West Gingin in 1995. In the sandy soils there it out-yielded many stocks including Trifoliata and Swingle, especially in the early years.
As with Volkameriana, fruit sugar and acid levels are usually lower than with other stocks and can drop relatively quickly.
Fruit should not be left on the tree too long or it can become bland. Imperial mandarins on this stock have had problems with internal granulation (drying), especially on sandy soils.