Origins of the Citrus Craze
One might think that citrus plants are just starting to enjoy a renaissance of sorts given all the attention they have garnered lately; but the true pioneer of collecting oranges and lemons goes way back to the reign of Louis the XIVth of France. Between 1684 and ‘86 he expanded the Orangerie at Versailles with parterres for summer viewing and an ornate glasshouse for the winter storage of more than a 1000 fruit trees, all grown in beautiful wooden boxes for portability. He then began to collect citrus from across the known world in order to diversify and extend the growing season, as many species flowered and bore fruit at different times of the year. And while few of us have the deep pockets that Louis had back in the day, we can still put together a fairly comprehensive citrus collection with a little patience. So here are some of the citrus that I have seen growing in the gardens and greenhouses right here in British Columbia.
It might surprise you to know that there are a few species of citrus which are hardy enough to be grown outdoors in coastal British Columbia. The most durable of these at USDA zone 5 is Poncirus trifoliata or hardy orange, with the contorted forms (‘Flying Dragon’ or var. monstrosa) being the most commonly available. I have had one growing in a container on my back patio for four years now and although both the form and fall colour are quite striking, you do need to look out for the prominent hooked thorns. The golfball-sized fruits are only borne sporadically and quite seedy, but the sour tangerine flavour works well in marmalades and gin tonics. The hardy lemon or Yuzu (formerly Citrus junos) can be grown in USDA zone 7 and I’ve seen more than a few healthy specimens in Vancouver and Richmond. Reliably evergreen in mild winters, it flowers in May with its slightly warty baseball-sized yellow fruits ripening any time from late October to November. These seedy lemons are prized for their flavour in Japanese cuisine and make a fine marmalade. Last on our list of hardy citrus is Sudachi, a hybrid of Yuzu and Mandarin orange which is also hardy to USDA zone 7. It is usually picked green and used as a lemon or lime flavouring in traditional Japanese cooking. All other citrus listed below will have to be container or greenhouse grown due to their frost tenderness.
Poncirus trifoliata 'Flying Dragon' fall colour, Poncirus trifoliata fruit, Yuzu tree in West Vancouver, Yuzu Fruit,
While many gardeners are under the impression the most common lemon available, Citrus x meyeri or ‘Improved Meyer’ (virus free), can be grown in a sheltered outdoors location, the only place I’ve actually seen this done successfully in on southern Vancouver Island. Bob Duncan of Fruit Trees and More has a beautiful Meyer Lemon espalier growing on the south side of his home which produces large sweet lemons year round with a little winter protection. These also grow well in containers and can be placed out in the garden from late April to May and brought into a sunroom when the weather cools, usually late September to early October. Other lemons you might come across during your travels to garden centres could include the variegated lemon (Citrus limon ‘Variegated Pink’) with its striped fruit and pink flesh (makes a beautiful lemonade), ‘Lisbon’ or ‘Genoa’ (both a little more cold hardy) or ‘Eureka’, the most common commercially-grown cultivar.
Meyer lemons, Variegated pink lemon, 'Eureka' lemon, 'Lisbon' lemon,
Admittedly, oranges are a little less common than other citrus but there are still a few interesting specimens out there. So let’s start with the sour oranges (Citrus x aurantium) which include the essential marmalade ingredient ‘Seville’ as well as Chinotto (var. myrtifolia), which flavours your favourite Italian soft drink. Blood oranges, a variety of sweet orange (Citrus sinensis) with distinct crimson-coloured flesh are also available from time to time, with ‘Sanguinelli’ being one of the better cultivars. Last but not least is ‘Robertson’, a common navel orange (Citrus sinensis) which seems to adapt well to container culture.
'Seville' orange, Blood orange 'Sanguinelli', Navel orange 'Robertson',
The diversity of limes brings with it a lot of potential for the foodies out there. The Key Lime (Citrus aurantifolia) is well known for its pie fame while the thornless version (‘Mexican Thornless’) are staples at every well-stocked bar. The Kaffir Lime (Citrus hystrix) is grown mostly for the tasty leaves used in Thai food, but the rind of the warty fruits can also be grated and used as a spice. Hybrids such as the Limequat (Citrus x floridana) add a unique combination of Key Lime and Kumquat flavours to cocktails or chicken dishes. But as far as I’m concerned the real highlight here is the Finger Lime (Citrus australasica) with its tapered digit-like fruits that break open to reveal tangy pearls of edible beads that literally burst in the mouth. This vegetarian caviar is the perfect garnish for a fresh taco or mixed drink.
Key Lime, Limequat, Finger Limes, Finger lime caviar,
Odds and Ends
Calamondins (x Citrofortunella mitis) may look like little oranges but this kumquat-mandarin hybrid has a distinct lime flavour. It comes in an attractive variegated form (‘Variegata’) and is a staple of Filipino cuisine. The Cocktail Grapefruit (Citrus x paradisi ‘Cocktail’) or Mandelo is a pomelo-mandarin hybrid with softball-sized fruits that have a distinct grapefruit flavour. Kumquats (Citrus japonica) are perhaps one of the most common indoor citrus and were introduced to Europe by the famous plant explorer Robert Fortune way back in 1846; the most common cultivar available is ‘Nagami’. Mandarins complete our look at available citrus and while they have been a part of many important hybrids, as a species (Citrus reticulata) they can be a little hard to find. When available look for ‘Shasta Gold’, ‘Pixie’ (smaller, intensely flavoured fruit) and ‘Gold Nugget’ with its unusual pebbly skin.
Calamondin, Variegated Calamondin, Cocktail Grapefruit, 'Nagami' Kumquat
Container Citrus Check-List
Since you are going to be growing most of your citrus in pots, here’s a list of essential needs to keep you on track;
1. Citrus require a minimum of 6 to 8 hours of bright sunlight, so consider using a grow-light during the darker winter months.
2. They prefer infrequent deep watering, with yellowed or curled leaves often being a symptom of overwatering. Use tepid water in winter.
3. Choose containers with adequate drain holes and do not leave the bottom of the pot in a saucer filled with water.
4. Citrus have lower phosphorus needs (as compared to nitrogen) and should only be fertilized once a month while in growth (April to August).
5. Choose a well-drained potting mix with perlite, vermiculite, coir or peat moss; avoid those with a high compost base as these stay too moist.
6. Check often for pests (spider mite, mealybug and scale) and treat with an organic pesticide as soon as detected.
7. Acclimate plants when going inside or out, and avoid drafts or forced air vents when growing inside.
8. Remove all suckers below the root graft, prune out weak or dead branches from late winter to mid spring.
9. While most citrus are self-fertile, a little hand pollination using a natural hair painter’s brush will increase production on indoor specimens.