May is the month I get the most questions about pruning. The fruit set is slowing, the nights are getting cool, and people stand in front of their plants holding secateurs wondering whether to chop back or leave alone. There’s no single right answer — it depends on the variety, the plant’s condition, and what you’re trying to achieve over the next six months — but there’s definitely a wrong answer, and I gave it for years.

The wrong answer is “prune everything hard now and the plant will reward you in spring.” It will not. It’ll sulk, sometimes die, and even if it survives it’ll be three weeks behind a less-pruned neighbour. I learned this in 2021 when I hard-pruned a row of mature Aji Limos and lost two of three plants over winter. Never again.

Why Pruning Matters at All

A chili plant is a perennial in its native range. We grow them in Sydney as if they’re annuals, but most Capsicum chinense and many baccatum varieties will overwinter here with care, and a second-year plant fruits earlier and more heavily than a first-year. Pruning is part of carrying a plant through to year two without it dying or going leggy.

The other reason to prune is hygiene. Plants that have been pumping fruit since November are tired. They’ve often got dead branches, sun-scorched leaves, fruit you missed that’s now mouldering, and aphid colonies under the leaves. May is a good moment to clean all of that up before winter sets in.

What I Cut In Early May

Three categories. Dead or dying branches — anything browning, snapping easily, with no living growth. These are pure liabilities heading into winter; they harbour fungal spores and sap energy. Cut them back to a healthy junction and bin (don’t compost) the offcuts.

Crossing branches in the centre of the plant. Chili plants throw out a confused tangle in the middle as they mature, and that creates poor airflow which encourages fungal issues in the cooler months. I take out maybe two or three of the worst offenders, opening up the centre slightly. Don’t gut the plant.

Any fruit that’s not going to ripen. If a chili is still fully green in the first week of May with no colour break, it’s not ripening this season. Pick it green, use it in a stir-fry, and let the plant put its energy elsewhere. Same with flowers that are still appearing — pinch them off now. The plant will not finish setting and ripening fruit from a May flower in Sydney conditions.

What I Don’t Cut Yet

Healthy leaves that look tired. Yes, they look ratty. But they’re still photosynthesising on the warm days we still get in May, and the plant is using that energy to lay down reserves in the roots and lower stem for winter. Don’t strip foliage. Wait until June or July when the plant has clearly gone dormant.

The main framework branches. The “Y” of the first major fork and the next fork up. These are structural, and you only do hard structural pruning in late winter, when the plant is dormant and the risk of frost damage to fresh cuts is minimal. Hard pruning in May exposes fresh wood to a cold, damp couple of months and that’s how plants die.

The growing tip if it’s still green. Some growers pinch the apical tips to encourage bushiness. May is too late for that strategy in Sydney. The plant doesn’t have time to compensate before dormancy.

My Late-Winter Hard Prune

I do the real reduction in late July or early August, when the coldest part of winter has passed and the plant is at its dormant low. I’ll take a Habanero or Scotch Bonnet down to a 30-40cm framework — the main stem and two or three healthy lateral branches stubbed at maybe 15cm each. New growth comes from these stubs in September and the plant is into flower again by November.

That’s the strategy that works in Sydney. Light tidy in May, hard cut in late July. The opposite of what intuition suggests.

Variety Notes

Annuums like Cayenne, Jalapeño, and Birds Eye don’t overwinter as reliably as chinense. I treat most annuums as annuals — let them finish their last fruit, pull the plant in late May, mulch the bed. The exception is a couple of really productive annuum specimens that have shown willingness to survive a Sydney winter; with those I prune as above.

Baccatum (the Aji family) overwinters well if you’re patient. Same May approach.

Pubescens (Rocoto, Manzano) actively prefer a cool season — these need almost no pruning at all and resent being chopped about.

Tools and Hygiene

Sharp bypass secateurs. Sterilise between plants with a wipe of metho or a dilute bleach solution — chili plants share viruses readily and your secateurs are the most efficient transmitter. The ABC Gardening Australia team have done segments on this for tomato pruning and the principle is identical for chillies.

Dispose of cuttings in the bin, not the compost. Pepper-mild-mottle and a few other viruses survive composting and you’ll spread them around the garden the following year.

A Pile of Green Fruit on the Bench

When you prune the under-ripe fruit off, you’ll end up with a bowl of green chillies that don’t look like much. Don’t waste them. Green chillies make a brilliant Thai-style green nam pla prik, or chop and freeze for cooking through winter, or pickle them in a hot brine. They’re not as fruity as a ripe red, but they have a fresh, vegetal heat that’s good in its own right. Good Food has decent recipes using green chillies if you need ideas.

May pruning isn’t dramatic. It’s a tidy. The dramatic prune comes later. Hold your nerve, leave the structure, and your plant will be cropping again before you know it.