growing limes

The lemon’s slightly less well-known cousin, the lime, has become a culinary stalwart in recent years. I knew it as a child only from the flavour of the rather odd-tasting Rose’s lime cordial and an array of lurid green lollies, but its beguiling floral-tart flavour always saw me saving the green ones till last when prioritising the eating order of a handful of colourful sweets. When allowed the occasional Popsicle in summer, photographic evidence shows the almost-fluorescent green lime-flavoured ice block was my preferred choice. Perhaps it’s my family’s seafaring genetics, filtered down through the generations that leave me predisposed to craving that ‘limey’ flavour.

Having only ever grown lemons in the past, I’m not sure what made my Mum decide to plant a lime tree in our West Coast backyard. The tree has flourished in the mild climate and is now a good three or so metres tall and almost as wide. It is a prolific producer of juicy green-yellow fruit, no doubt thanks to the ample rainfall, and has survived both major cyclones and flooding events with little more than a gentle prune and a sprinkle of fertiliser each year. It grows happily in the combined shade of a walnut, apple and fig and keeps scurvy far from the door of our family and friends.

If you live in a relatively frost-free climate and are either a culinary or cocktail aficionado, keen to avoid over-priced imported citrus fruit in the off-season, or just looking to increase the self-sufficiency quotient of your backyard, a lime tree might be just the ticket.

Limes: a short family history

As with many types of citrus, the array of fruits called the name ‘lime’ are actually quite genetically diverse, and therefore cannot be grouped under one specific taxonomic unit. Citrus species also hybridise easily, hence many commonly-known varieties are actually hybrids. For simplicity’s sake, in this article I’ll deal with the types we most commonly encounter in New Zealand. It is also important to make the distinction here between the trees known as ‘lime trees’ in Europe (lindens), which are a completely different group belonging to the genus Tilia, and the Citrus fruit limes.

As with other Citrus species, limes belong the Rutaceae, or rue family. There are two main species of lime that are grown commercially: the Mexican lime (also known as the West Indian or key lime, which is actually native to Southeast Asia) Citrus x aurantifolia; and the less-acidic Tahitian or Persian lime, Citrus x latifolia, (itself a cross between Citrus x aurantifolia and the true lemon, Citrus limon), which was first cultivated in Iran and southern Iraq. The Mexican lime is thought to have found its way to Europe via North Africa, the Middle East and the Mediterranean with the Crusaders, and to Mexico and the Caribbean with the Spanish. It requires high humidity combined with high night time temperatures to produce well.

An Australian native, the finger lime (Citrus australasica) is currently very popular in culinary circles, as the thin-skinned, finger-shaped fruit are easy to pop open and the fleshy juice-filled vesicles contained within are highly decorative and used as ‘citrus caviar’. Another popular culinary lime, again a tropical Southeast Asian native, is the crinkly, wrinkly, brain-like Makrut lime (Citrus hystrix), valued more for its fragrant leaves and rind than its juice. The limequat, a Citrus x aurantifolia/kumquat hybrid is a small-fruited but flavour-and-juice packed option for cooler climates, with the added advantage of being suitable for pot culture.

Historically, during long sea voyages the vitamin C deficiency known as scurvy was a huge problem for seafarers on limited rations consisting largely of dry goods, preserved meat and ale. In the 19th century, the British navy introduced a literal secret weapon against this scourge, which allowed crews to remain at sea for longer periods – the introduction of a daily ration of vitamin C-rich lemon juice (which later was substituted with lime juice, hence the sailors’ nickname ‘limeys’). Distilled lime essential oil is widely used in cosmetics and perfumery, but can cause sunlight-induced skin damage if applied topically. In modern times, scurvy is pretty rare thanks to our much-improved diets, but limes still play a large role in flavour enhancement in a number of cuisines. Worldwide production of commercial fruit is led by India, Mexico and China, with the New Zealand industry producing around 700 tonnes per year, primarily for the domestic market.

Suitable climates and growing conditions

Limes are attractive evergreen specimen trees, with their small to medium size (two to four metres at maturity) making them well-suited to the home garden. Sensitivity to frost is this subtropical’s main downfall, so if you live in a region where other citrus species fail to thrive, limes are probably not for you. In terms of cold-tolerance, limequats are the most cold-hardy, followed by Tahitian/Persian types, with the Mexican lime being the most cold-sensitive. Limes and limequats grow very well in pots and tubs when provided with adequate moisture and nutrition, and can be moved inside to a conservatory or similar in cold weather.

Lime flowers are insect-pollinated, with the flowers possessing both male and female parts (monoecious and bisexual and therefore mostly self-fertile, with only one plant being necessary to ensure a crop). Even in light of this, most fruit forms parthenocarpically (without fertilisation taking place), especially in the Tahitian varieties, which has the added bonus of the resultant fruit being seedless – no straining of juice required when you mix those cocktails! Fruit matures five to six months after fruit set – Tahitian/Persian limes are the most commonly commercial variety in New Zealand and the main crop is harvested from May to July. Summer crops are small, if not absent. Fruit will store well on the tree however, and this makes it possible to harvest fruit almost year-round in the home garden setting. Seedlings will produce fruit after about three to six years, and clonally propagated trees in their second or third year. It is not uncommon for mature trees to produce crops in excess of 20 kg/tree.

Mexican limes are often propagated from seed, as offspring are usually true to their parents. For other varieties, it is possible to propagate from cuttings, but these often only form weak root systems. If the parent tree produces suckers at the base of the trunk, the simplest propagation method is to dig these up, pot them and grow them on. If you fancy trying some more sophisticated techniques, air layering with the use of a rooting hormone and grafting or budding on to suitable rootstocks (e.g. bitter/sour orange, Citrus x aurantium or rough lemon, Citrus x jambhiri) are also options. On the whole, you are best to cut your losses and purchase a healthy commercially-raised plant from your local nursery or garden centre.

Site selection and planting

Choose a sheltered site in full sun – limes will not tolerate wind or the salty conditions of coastal locales. Limes do not transplant well, so choose your site carefully, and allow approximately five metres between trees for Tahitian/Persian limes and about seven metres for Mexican limes. Plant from late autumn through to early spring in warm regions but wait until August or September in cooler areas. A shelter structure enclosed in windbreak-type cloth will be of assistance in the establishment phase in more marginal climates. Limes are tolerant of a range of soil types, provided there is adequate drainage, but do not tolerate heavy clays and the waterlogging that often accompanies them.

Culture and care

Limes tolerate moisture stress a little better than other types of citrus, but fruit best with an adequate year-round water supply. Thick skins and dry flesh may result if the tree is placed under water stress for extended periods of time.
A balanced citrus fertiliser should meet the needs of your lime tree – the amount required should be calculated according to the label directions and split into two or more applications, two-thirds applied in late winter/early spring and the other third in late summer. Spread the fertiliser around the base of the tree to the dripline (the zone underneath the outer circumference of a tree’s canopy, where water drips from onto the ground when it rains). Aim for a coverage of about a cupful of fertiliser per square metre of ground. Mulch containing rotted seaweed can also be useful as the potassium it provides is beneficial for fruit development.

Pruning

As with other citrus trees, limes generally form their own neat structure and so little in the way of major annual pruning is required – in fact, it can actually be detrimental, as evergreen species such as citrus store their reproductive reserves in the leaves and over-pruning will remove this stockpile, resulting in reduced or no fruit set. Flowers are borne on the new season’s growth and pruning at the wrong time will also knock off your crop. On the flipside, over-cropping one year can lead to biennial bearing – or a small or non-existent crop the following year, so if the fruit set is particularly heavy one year, thin off the excess fruit to ensure a balanced crop the subsequent year as well.
Follow the standard rules for of removing the “three Ds” (dead, damaged and diseased wood) for general maintenance pruning after the main harvest is complete. Also keep an eye out for suckers forming at the base of the tree and remove those too. Don’t forget to seal any pruning cuts with paint such as Yates Bacseal®

Pests, diseases and what to do about them

Limes are susceptible to several of the more common citrus diseases, including verrucosis (fungal scab) and brown rot. A copper spray (e.g. Yates Liquid Copper, applied according to label directions) in November or December once the fruitlets have formed should help – this can be repeated again in late autumn/early winter. If you notice black sooty deposits on your lime tree’s leaves, you likely have an infestation of scale insects. Yates Conqueror Oil applied at label rates during February and again in May should take care of these as well as other sucking insects like mealybugs, and also mites.

The New Zealand endemic lemon tree borer beetle (Oemona hirta) also takes a fancy to lime trees, so make sure you conduct any pruning outside of egg-laying season (roughly September to January) and seal any pruning cuts immediately with pruning paint. See Your Backyard Fruit Bowl: Beyond the Meyer Lemon for more detailed information about the lemon tree borer.

Varieties: My top picks

Tahitian/Persian limes are the most reliable choice for the New Zealand climate and several selections are available. They are medium-size trees at maturity, more vigorous but less thorny than Mexican/West Indian limes and also have a slightly thicker skin than the latter.

Tahitian – small, oval, relatively thin-skinned, juicy, seedless fruit which ripens to yellow from green. Main crop is ripe in winter.

Bearss – similar to Tahitian, thought to be either a hardy Tahitian seedling or indeed just a synonym. Crops in second or third year, can produce larger crops of fruit with noticeably superior characteristics to other Tahitian selections. First found in the orchard of nurseryman Mr. T. J. Bearss of Porterville, California in 1895.

Limequat ‘Eustis’ – Reasonably cold-tolerant Mexican lime/kumquat hybrid producing good quantities of small, thin-skinned lime-like fruit about 3 cm in diameter. The sharp-flavoured, juicy fruit can be quite seedy (but makes excellent marmalade) and is ripe in autumn and winter. Suitable for container culture.

Finger lime – very small-leaved, thorny Australian native, growing to two to three metres in the New Zealand climate. A bit more cold-sensitive than Tahitian limes, so perhaps one for those who dwell in the winterless north. However, can be grown in containers you Mainlanders! The finger-shaped fruit have thin skins and jewel-like flesh - ripening from autumn to early winter. Great novelty value but keep kids and pets clear of the thorns.

What to do with your crop

Limes are among the more popular and trendy fruits, but can reach eye-watering prices in the New Zealand off season (think $40-$80, yes $80 per kilo), which happens to be bang smack in the middle of summer when we all need lime juice for summer drinks, salad dressings and guacamole…

Avoid the overpriced, under-ripe, rock-hard imported fruit by acting now to secure your summer supply. Squeeze juicy ripe yellow limes when they are cheap and plentiful, pour the juice into ice cube trays, freeze, and then free-flow bag the cubes. Freeze larger quantities in plastic tubs for cordials and desserts. Make lime curd (Nigel Slater’s lemon curd recipe from the Observer online is my go-to) and freeze in tubs to fill cakes with, and to serve alongside pancakes. Grate the zest, mix with some juice, pack into ice cube trays and free flow as for juice above for any recipes requiring lime zest, e.g. cakes and icings. Lime juice is a key ingredient in the many and varied marinated raw fish salads of Pacific, South American and Asian cuisines.

Limes make fantastic marmalade, with their thin skins and seedless flesh making preparation a doddle. Interestingly, lime marmalade takes on a cloudy hue and goes a bit solid if refrigerated – it doesn’t affect the taste, but I’ve noticed it’s the only type of citrus marmalade that is affected this way. Try a big spoonful in the mixture for your next fruit cake for extra zip and zing.

Lime pickle, in either a cooked or uncooked style, is an excellent accompaniment to curries. I’m a big fan of the uncooked (salted) version, which has a really fresh flavour. A little goes a long way, it keeps almost indefinitely in the fridge and is a great way to use up every little last lime on your tree. A teaspoon mixed with a generous dollop of mayonnaise makes a statement when used in burgers and wraps or served alongside fried fish. At the recommendation of a friend, I’ve taken to adding a spoonful when I steam rice for serving with curry – any leftovers make great fried rice too.

Lime pickle

Small limes, quartered, or larger limes, sliced into 0.5 – 1 cm rounds or half-moons
Plain (table) salt – it is of utmost importance that you DO NOT used iodised salt, the mixture will discolour something chronic
Fresh turmeric root (can substitute dry/ground)
Fresh ginger root
Extra limes for juice
Neutral vegetable oil, for sealing

Sterilise a large glass preserving jar or jars, of sufficient capacity to hold the quantity of limes you wish to use (hot soapy rinse, then place in oven set to 125°C for 30 minutes. Remove and place on a wooden board to cool, covered with a tea towel).

Quarter or slice limes, and for every cup of prepared fruit you will need ¼ cup plain salt. Mix the limes and salt together in a large, non-reactive (glass or plastic) bowl. Add 1 tsp ground turmeric or a thumb-size knuckle of grated fresh turmeric, plus 1 tbsp grated fresh ginger for every three cups of prepared limes. Mix well and pack into the sterilised jar/s. Top up with extra lime juice so the fruit is completely submerged, fix a clean cloth over the mouth of the jar with a rubber band, and leave on your kitchen bench for 10 days. I like to give the mixture a stir with a sterilised spoon every three days or so. You will see the fruit and its peel start to soften and break down over time.

To store, sterilise some smaller glass jars in the oven as detailed above. I like to use jars with non-metallic lids for this purpose, as the pickle’s very high salt and acid content quickly erodes even enamelled metal lids. Vegemite jars are perfect – just dip the plastic screw-top lids briefly in boiling water to sterilise.

Pack the pickle firmly into the jars, avoiding air bubbles. Top with a thin layer of oil and screw on the lids. I like to store this at the back of the fridge – I’ve noticed pickles containing turmeric will often lose their bright colour when exposed to sunlight for long periods.

Add a generous teaspoon of pickle for every cup of uncooked rice before cooking using your favourite method. I steam my rice by selecting a bowl that fits inside the steamer insert of a large saucepan, placing the dry rice (and lime pickle) in it and covering the rice with ¾ inch of water above the level of the rice. Fill the lower saucepan with water, set over high heat and steam until the water in the top (rice) bowl has been absorbed and the rice is cooked. You can then turn off the heat so the rice keeps warm without sticking or burning.


Anna-Marie Barnes is an active member of the New Zealand Tree Crops Association who endeavours to grow and preserve as much of her own fresh produce as possible. When the weather’s no good for gardening, she can usually be found inside working on a batch of homemade cheese or soap.

The New Zealand Tree Crops Association is a voluntary organisation promoting interest in useful trees, such as those producing fruit, nuts, timber, fuel, wood, stock fodder, bee forage and other productive crops. Find out more about the NZTCA here: https://treecrops.org.nz/

Image credits
Tahitian lime fruit – Image by Forest & Kim Starr, CC BY 3.0 US https://creativecommons.org/licenses/by/3.0/us/deed.en, via Wikimedia Commons
Basket of limes – Image by Ray Shrewsberry, via Pixabay.com
Cut limes - Image by Johanna Pakkala via Pixabay.com