4 minute read
Gardening
Crushing It! WORDS LYNDA HALLINAN
They’re a sour lot, the citrus clan. They’re all lemon lips and acid tongues, or at least they were until the mandarin and the pomelo got together a few centuries ago to add some sweetness to the gene pool.
All the citrus we eat today share four common ancestors: the pithy citron (Citrus medica), mandarins (Citrus reticulata), prodigious pomelo (Citrus maxima) and largely unpalatable papeda (Citrus cavaleriei). However, thanks to plenty of hanky-panky and hybridisation, their family tree now looks like a complicated Venn diagram sketched by a children's spirograph. Take the lemon (Citrus limon) we all know and love for winter cordials, cakes and curds. Genomic sequencing suggests this most versatile of juicy winter fruit is a hybrid of the citron and the bitter Seville orange (Citrus x aurantium), which in turn is a pomelomandarin hybrid. The Tahitian limes (Citrus x latifolia) we squeeze into cocktails and Nuoc cham are the offspring of lemons and the Mexican key lime (Citrus x aurantiifolia), which in turn is the child of a Filipino papeda and a citron. Tangerines were bred from pomelo and mandarins, while tangelos are an incestuous cross between a tangerine and a pomelo. The yuzu's parents are the papeda and the mandarin; ugli fruit are oranges crossed with grapefruit; and the Ponderosa lemon is a citron-pomelo hybrid.
Bear with me. Oscar Wilde once described the grapefruit (Citrus x paradisi) as “a lemon that saw an opportunity and took advantage of it”, but it actually arose from a West Indian holiday romance between a Jamaican sweet orange (Citrus sinensis) and an Indonesian pomelo. And, because every family needs a long-lost relative, the makrut lime (Citrus hystrix) and kumquats (Citrus japonica) were only recently welcomed back into the fold, having formerly been fostered by the Fortunella family. Okay, okay, no one likes a smarty pants, so I'll stop there and offer advice for keeping all these citrus trees happy and healthy. As citrus are mostly subtropical in origin, they can tolerate light frosts but they certainly won't thank you for it. My lemon trees lose all their tender tips to Jack Frost but spraying with the organic wax-based protectant sold in garden centres as Wally’s Vaporgard makes a big difference (use it on passionfruit and subtropical vireyas, too). Yellowing leaves suggest the need for a feed, while margined or mottled foliage reveal mineral deficiencies. On both counts, wait until spring, when the trees return to active growth and warmer soils allow the uptake of slow-release citrus fertilisers, then apply liquid leaf-greening tonics such as Yates Magnesium Chelate or Yates Zinc and Manganese Chelate. Scale, aphids and whitefly tap into the sap of citrus trees and excrete sugary honeydew that black sooty mould grows on. Tackle the former and you'll deal to the latter, which can simply be washed off with soapy water. As for citrus verrucosis? The fungal disease that causes scabby skins is largely cosmetic, but if it bothers you, spray with copper to clean up the infection. Should you encounter squishy patches on the sides of ripe fruit, the pesky guava moth caterpillar is most likely the culprit (sorry to say there’s no easy way to foil this foe), while the calcium deficiency known as blossom end rot causes dry fruit with sunken bottoms. Make a note in your diary to fertilise your trees at Labour Weekend to avoid it next season. Oh, and if you need to prune your citrus trees, it’s safe to do so now. As a rule, between the A months of April and August, the native lemon tree borer beetle, Oemona hirta, isn’t out and about looking for places to lay eggs.
Janet from Pacifica Home and Garden says, “Citrus can grow very successfully in pots providing both fruit and an attractive foliage plant. We recommend feeding in spring and late summer with a slow release fertiliser and ensure they are kept well watered during the hotter months. Remove spent flowers to encourage repeat flowering and prune to maintain shape, especially if you are going for the topiary look. Make sure you stake firmly until established and avoid exposure to windy situations.”
Seasonal Checklist
• In winter, I focus mainly on the parts of my garden I can see between getting out of the car and getting in the front door. There's no harm in cheering yourself up with cheap flowering annuals—pansies, polyanthus, calendulas, cyclamen, Iceland poppies and ornamental kale—for an instant pop of colour in pots. • Sow hardy winter salad greens such as peppery wild rocket, miner’s lettuce, purslane, lamb’s lettuce, mesclun mixes and baby cos. • Grow salad crops in containers, as potting mix remains consistently warmer than garden soil, allowing for faster, cleaner growth (no mud splash).
Feed potted crops weekly with liquid fertiliser diluted in warm water. • Rake up the last fallen autumn leaves before they turn to sludge on paths and driveways and smother emerging bulbs and winter annuals in borders. • For spring, sow your favourite fragrant sweet peas, climbing ‘Sugarsnap’ peas and blocks of broad beans.
Sow direct.
Lynda Hallinan
Waikato born-and-raised gardening journalist Lynda Hallinan lives a mostly self-sufficient life at Foggydale Farm in the Hunua Ranges, where she grows enough food to satisfy her family, free-range chooks, kunekune pig and thieving pukekos. She has an expansive organic vegetable garden and orchards and is a mad-keen pickler and preserver.
