Citrus - Mandarin Imperial Citrus reticulata Grafted

What the Riverside collection records for Imperial is its fruit, its season and its orchard habits, not its culture. It is an extremely early maturing mandarin, equal in that to the Owari satsuma: in the collection's notes on Australia the sugar to acid ratio reaches seven to one around mid-March in the earliest regions and early June in later ones, and the fruit can be harvested up to July or August, depending on the region.

The tree is vigorous and upright, by the collection, with a tendency towards alternate bearing that is sometimes managed by thinning, and cross-pollinators may help with set, yield and size. Granulation of the flesh is sometimes a problem because of the low juice content.

For the plant itself the only other reference read is the CSIRO rainforest key's account of the mandarin species: usually a shrub of 2 to 4 m that occasionally grows into a small tree, with very aromatic leaves and pleasantly perfumed flowers, an introduced plant occasionally found naturalised in north-east Queensland. That height is the species' and is the one on the facts card. No reference read gives Imperial a height of its own, or a sun, soil, water or frost note.

Imperial is a fruit variety, and what the collection gives is how its crop is handled. The fruit generally has to be clipped from the tree, not plucked, and fruit harvested early needs de-greening. The collection adds that Imperial responds poorly to the heat and cold treatments used for pest disinfestation, which makes it unsuitable for export from Australia. The 1967 description the collection quotes says its early maturity, appearance and flavour earned it a premium in the markets of that time, and that it loses quality if left on the tree after maturity. The collection names Emperor as a possible parent. The HortOS community garden cost guide lists Imperial among the plants it prices. No reference read gives a spread or a planting centre.

The HortOS listing names Imperial as a grafted tree, and the table above shows the sizes growers list. What to look for in the roots, stem and canopy of nursery stock is in the HortOS nursery plant quality guide. Stock crossing a state border travels under the state and territory biosecurity rules on moving plants and soil. The drawbacks are the collection's: a life after harvest of only two to four weeks, de-greening for early fruit, granulation at times and a lean towards bearing in alternate years.