Citrus - Calamondin Citrus x. microcarpa (syn. Fortunella)

Every growing note here comes from two American references, the NC State toolbox and the University of California Riverside citrus collection; no Australian reference read gives climate zones, a frost figure or a pruning note.

Position and soil, by the toolbox: full sun and high humidity for the best flowering and fruit, in fertile, moist, well-drained soil high in organic matter, acid to neutral.

Cold: the collection calls calamondin cold-resistant, and the 1967 description it quotes says strongly so; the toolbox says sources vary on its growing zones, and for colder winter areas it advises growing it in a container and bringing it indoors for the winter.

Flowering and fruit: the toolbox has it blooming in spring and repeating four or five times in the season, so that flowers and fruit can be seen together, and says a fruit can take up to a year to mature. The collection says the tree flowers and sets fruit intermittently throughout the year, and the description it quotes says the fruit holds on the tree remarkably well.

The toolbox gives stem cuttings for propagation and describes the stems as nearly thornless. Its pests are spider mites, scale insects, citrus leafminer and aphids, and its diseases citrus canker, sooty mould, citrus greening and root rot; that is an American list, not a record of what the plant meets in Australia.

No Australian reference was read for its status in Australia. The Atlas of Living Australia search holds records only from Christmas Island and New Ireland and says nothing of status, so the exotic status on the facts card rests on the native range the toolbox and the Riverside collection give, which is Asia.

The uses on record are American too. The Riverside collection says calamondin is planted there primarily as an ornamental, in the ground or in a container, and the toolbox lists it for containers and patios, for an Asian or a winter garden and for its edible fruit, which adds a tangy flavour to drinks and to foods such as noodles. The collection quotes a note that the Philippines has a growing industry in calamansi juice. The toolbox records, for the United States, that the flowers attract pollinators and birds eat the fruit. A variegated form with marbled leaves and faintly striped fruit is sometimes marketed in the United States as Peters, by the collection. The description the collection quotes adds that calamondin makes an excellent rootstock for the Nagami kumquat when that is grown for the same purposes, as a potted or tubbed plant. No reference read gives a planting centre.

The names vary. GBIF and the NC State toolbox use Citrus × microcarpa; the Riverside collection heads its page × Citrofortunella microcarpa and also writes Citrus madurensis; the HortOS listing adds Fortunella as a synonym, a name none of the references read uses for this plant. 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 the references give: acid fruit that can take up to a year to mature, and the pests and diseases on the toolbox's American list.