Plant profile- Citrus

Citrus were one of the first fruit trees I planted on the farm shortly after moving in. I did the usual thing of buying expensive grafted trees (more acceptable when I was still working full time) and then planted them out during a very wet season, with the large holes I had to dig for their congested roots filling up with water as I dug them. Since I was away from the farm during the week I figured this was a more acceptable risk than having them dry out in their pots without me watering them regularly. Shortly after they were planted we entered a severe six month drought that saw me carrying buckets of dam water most weekends to keep them going. The size of the plants meant that it would take them a long time to send roots out and become properly attached to the soil. Life moved on and my focus shifted to other priorities. I stopped watering when the drought broke and once a year I would pull the grass back from their bases. When the pasture grasses died back in 2018 I stopped weeding them and cobbler’s pegs up to 2 m tall grew around them. After four years the trees had grown to 2-3 m tall but the fruiting was pretty meagre. I chastised myself for not doing all the things you are supposed to do and buying all the things you are supposed to buy to force your trees to be productive whether they feel like it or not.

Then 2019 happened and we were drowned in citrus fruit. So many mandarins we shifted from eating them whole to juicing them. I started selling them at the local shops. I made mandarin and jam melon jam. I did nothing different to earn this bounty other than waiting. Other friends in the area reported the same thing. It was just an especially good year for citrus. Like all plants that are not shielded from the vagaries of the weather they will have good years and bad years. And like all living things not pushed along with industrial inputs they will have their own natural seasons and rhythms. Mandarins herald the start of citrus season in late autumn, stretching into mid-winter. Then the navel oranges are followed by the Valencia lasting into late spring. True lemons fruit mainly through autumn and winter, complemented nicely by Meyer lemons that fruit more sporadically through the summer.

Wanting to liberate myself from the hassles of grafted trees I looked into the alternatives. Many types of citrus are polyembryonic, meaning their seeds are predominantly clones of the parent. I had planted all my mandarins together on one dam edge to allow even the few percent cross pollinated seeds from them to still be mandarin. The oranges and grapefruit were a bit away from the lemons and lime. Oranges, limes and true lemons also tend to come true from seed. Grapefruit, pomelo and Meyer lemons are more recent hybrids between unrelated citrus species and give more variable seedlings. Luckily I either don’t want to grow them (grapefruit overlap with the long season of Valencia oranges) and just a couple of Meyer lemon grafts are enough to produce a few lemons through the summer. Years ago I stumbled across a seed grown spiny mandarin in a fruit tree catalogue and added to the order. It arrived only 10 cm tall, was plonked in my old orchard and ignored. Five years later it produced a respectable crop of fruit more sweet and easy to peel than any of my grafted trees. The spines were also no worse than some of the grafts and diminished as the tree grew. It formed a more upright tree so we needed a ladder to pick all the fruit, but this is a reflection of it having a stronger root system. Citrus in our district are relatively unbothered by pests, and citrus being an intensively grown crop sure has plenty to worry about. Avoiding fertiliser probably helps a lot as plants overloaded with nitrogen are a magnet for pests. Our naturally magnesium rich soil probably suits them. Fruit trees, especially grafted ones, are fairly short lived organisms. Rather than fighting borers I would rather always have vigorous young trees coming on to replace the old ones as they fizzle out.

Seed was collected from the spiny mandarin were collected as we ate and sowed. Citrus seed are unable to survive drying out and must be kept damp until sowed. This is a fairly common trait among fruit tree seeds and explains why citrus seed are almost never offered in seed catalogues. The seedlings germinated readily in group pots and were potted on into small tree tubes. I hoed the spots clear and laid a little goat manure in each position, then pre-dug the holes with a shovel. These were planted out in a grove near the house, mixed in with acerola and mulberry. It was raining at the time of planting so they needed no irrigation. I put three seedlings in each position so I can thin to the best one later.

Instead of my usual core flute tree guards I tried an alternative. I hammered six slit bamboo stakes into the ground around each tree in the shape of an inner triangle with a second triangle just outside the first. This created gaps that I could fit short sections of Tithonia stems into from a nearby hedge planting. By alternating which side of the triangle I was filling I could gradually build up the walls of the shelter. I built them up to about 20-30 cm, just above the tops of the trees. Since then they have held up well, with a few weeds growing around them but not enough to cover the young trees too much. In the six months since they were planted the seedlings have advanced from 10 cm to 20 cm tall. Plants established at a small size often seem to barely grow for quite a while as they establish a good root system then race away later.

Since this time I have collected seeds from seedy Valencia and navel oranges (yes old strains do sometimes have a few seed) plus true lemons. It is important when collecting seed to not cut straight through the fruit as this often damages seed. Instead cut around the outside then twist the two halves apart. I am aiming to only grow mandarins, true lemons and oranges from seed since these species complement each other nicely. There is an optimum level of diversity between monoculture and one of everything. I need to be careful to not grow too much citrus since it is a fruit with a limited shelf life and few options for preservation. Freshly picked ripe fruit that isn’t dipped in wax like in the supermarket shrivel up in days. Jam is very time consuming to make and we don’t eat much refined sugar any more. Selling surplus during bumper years sounds nice but the logistics of picking, carrying, sorting, bagging, weighing and transport is a hassle on a small scale. I would rather end up with enough trees to just meet our needs during poor years. It is nice to look forward to the first mandarins of late autumn every year, but also nice to say goodbye to the last Valencia of spring as well. When you count your remaining years in seasons of fruit life sure is short but sweet.

Grafted trees weighed down with fruit, reminding me of battery meat chickens too fat to walk
The spiny mandarin seedling with an elegant upright form and more sensible burden of fruit
Close up of spiny mandarin fruit. Size, flavour, sweetness and ease of peeling were all excellent.

3 thoughts on “Plant profile- Citrus

  1. The seeds you gave me of ‘Spiny Mandarin’ had an excellent germination rate and have ended up as healthy trees. Mine are between Mulberry and Albizia pollards with overhead shade provided by a Inga alley. While they were started in pots of a standard bark-based potting mix, they are weathering these dry conditions nicely though I have given them the occasional supplementary watering (tap is only metres away).

    We had a heavy fruiting year of Imperial and Navel, Emperor didn’t do as well. Lime and Lemon were above average.


  2. When you say ‘true lemon’ does that apply to both the common varieties available—Eureka and Lisbon? Are these just varieties of the one species and if so where has the variation come from? I was aware that Meyer is a hybrid, but didn’t realise grapefruit was. I’ve grown a seedling grapefruit from a friend’s tree but it hasn’t fruited yet. I don’t like them to eat, just use them for mixed fruit marmalade.

    I have an Imperial mandarin which doesn’t do well. I read that they don’t do well in Melbourne. I gave up on it last summer (which was very dry here) and didn’t water it at all. It didn’t die, but it wasn’t very happy. The fruits are the size of walnuts and rock hard, not the large ones in the shops with nice loose rind. I have something called a Japanese Seedless mandarin which does a lot better with larger, sweeter fruit. That’s what the nursery called it, but I can’t find any info about it. I have a good Valencia and Washington Navel. I might try those from seed.


    1. As far as I can tell only Meyer lemons are of recent hybrid origin. The history of citrus species is a complicated mess, with a handful of original species that have been selected and hybridised in a very messy family tree. Even fairly well established species like Citrus limon (true lemons) is a cluster of closely related genetic lines. I grow other lemons like eureka and lisbon from seed, but even single named varieties have a fair bit of genetic variation on top of that. I will be able to let you know from personal experience how they perform from seed in a few years. Added into the mix is variations in rootstock, graft quality (grafts can partially fail years later), and root system quality. If you only had one imperial mandarin that did poorly any of these other factors could be behind it rather than the name on tag it came with. If your oranges are performing well I would strongly suspect the mandarin just had some flaw or was past its prime and wouldnt hesitate to try mandarins again. Grapefruit seed will still mostly produce grapefruit from what I have read, but the tree and fruit qualities are supposed to be a lot more variable than for other citrus. Like any variable you can just plant loads with a view to thinning back to the good ones later provided you have plenty of space spare.


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