Citrus Cultivars and Selection

Orange fruits and flowers - citrus cultivars

A large number of the citrus cultivars that we know here in Australia have their origins in plants that were imported from the US or Middle East. However, many of these introduced varieties mutated once here and it is these mutant variations, known as bud sports, that have become over time, many of the citrus crops that we think of as Australian.

Home gardeners and fruit farmers alike are quick to spot new fruits – especially if they are better than that produced by the parent plant. When such a development occurs, the grower will bud and nurture the plant to see if its fruit is sustainable. An example of this is the ‘Seedless Valencia’ which was first noted in Richmond NSM in the early 1920s. This variation on the much-loved Valencia orange is almost seedless. Similarly, the ‘Red Navel’ orange comes from a bud sport formed on the ‘Washington Navel’ at Mundubbera in Queensland. Again, it had very few seeds and a rich colour which growers seem to favour.

Citrus Cultivars – Chose Right for your Region

The most important thing to consider when selecting which citrus cultivars to plant is the advice of local and experienced growers who know the particularities of your region.

Gardeners new to raising citrus cultivars can be side-tracked by factors such as when the tree fruits and for how long. However, things like this can become irrelevant almost overnight if you choose a citrus that doesn’t like the soil in your region, or hates the lack of sunshine, or doesn’t get enough rainfall or would prefer to be nearer the coast.

It’s very simple really. If your citrus cultivar isn’t right for your area, it won’t thrive.

Reputable plant nurseries, garden centres and even supermarkets should purchase their citrus saplings and bushes from local wholesalers. This means that the rootstocks that they are budded onto should be suitable for your region.

We also have strict plant quarantine rules in Australia – between states and territories as well as internationally. This makes importing plant from outside your local area quite a challenge. And some places, like South Australia, prohibit their introduction all together.

See here for more on the restrictions around importing live plants.

The regulation are so tight that the propagators have an Elite Budwood Scheme in citrus growing states, where newly imported buds or local selections that are certified virus free buds are distributed to three citrus propagators in each state. These propagators then bud them onto their local rootstocks to trial for several years before releasing some of them. For the humble home gardener, most citrus cultivars are budded and nurtured for 2 years before they are sold on as resilient tub-raised citrus plants. This is why you don’t see ‘baby’ citrus plants unless you’ve raised them yourself from seeds potted on your window cill.

Given that mature citrus tend to be very hardy, young plants tend to be quick fussy. Whilst open rooted plants like deciduous nut and fruit trees will tick alone no matter what, citrus can be temperamental with some rootstocks reacting badly to any root disturbance and many citrus cultivars putting on growth during the chillier months. And then there is the 2 years that they can take for the bud union to mature on the rootstock and for them to become sufficiently strong. These are further reasons why you rarely see small citrus for sale.

Knowing the specific rootstock that your particular cultivar is budded to is unimportant beyond being aware that some rootstocks prefer clay soil and some acidic soils and so on. Similarly, there are specialised rootstock for dwarf varieties. If you buy locally, the propagator and seller should be aware of these considerations and have selected a suitable rootstock for the cultivar.

Finally, be aware that growers and retailers can be fairly flexible on the names that they give to different citrus cultivars and some common names are often either abbreviated or spelt incorrectly. You may even find that some retailers use a local promotional name not familiar in other parts of the country.

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