Trifoliata (Poncirus trifoliata)
Poncirus trifoliata or trifoliate orange has been used worldwide for many years and is commonly grown on heavy soils in WA. It produces small to standard-sized trees, depending on soil type. They bear well for their size, and fruit quality is good.
Trifoliata performs best on heavier clay loams to loamy soils and is not well suited to sandy soils where growth is slow. It is cold hardy but has poor drought tolerance and is poorly suited to saline and highly alkaline or acidic soil conditions.
This rootstock is resistant to citrus nematode, tristeza virus and some species of Phytophthora. It is very susceptible to the exocortis viroid. It is responsive to viroid dwarfing and suitable for use in replant sites.
Compatibility
Trifoliata is incompatible with Eureka lemon. Because of reports of incompatibility with some minor varieties, it should be used cautiously with untested varieties.
Local experience
Trifoliata has become less popular in recent years as it produces small trees that can take a long time to yield. It is not as tolerant of saline conditions — an increasing problem in some areas — as some other stocks. It is known for good quality fruit and is better suited to heavy soils. It has performed poorly in deep sands at West Gingin where trees are slow to reach a good bearing size.