Winter Gardening Tips Your Plants Will Love

While winters in Brisbane are somewhat warmer than others across the country (how lucky are we?), the weather still poses some challenges for gardening enthusiasts, including the lack of rain. But with our winters full of sunshine and warmth, gardening weather and flourishing crops can still be enjoyed. Here is our winter gardening guide, which covers pruning, mulching, water, feeding and pest control tips, and what to plant in winter in terms of flowers, herbs and veggies.

Pruning gardens in winter

Winter is an excellent time to prune certain plants in the garden, particularly in Brisbane. Pruning plays a vital role in promoting the overall growth and health of your garden. By removing certain parts of a plant, such as dead or diseased branches and leaves, pruning helps improve light penetration and air circulation, which helps to reduce the risk of fungal diseases.

Pruning encourages new growth by stimulating flowering and fruit production, and maintaining the desired size and shape of plants. It also allows you to remove weak or crossing branches, improving the structural integrity of the plant and preventing potential damage in the future.

However, make sure you research pruning timing and techniques for specific plants before going ahead, as not all plants appreciate a prune in winter. Essentially, pruning in winter is done for plants that are dormant during this time. These plants have already shed their leaves and are basically getting ready for their next season. A few plants that you can definitely prune in winter include:

• Roses. Reduce thick, strong stems by about half their height. Thinner canes can be cut back to a third as this will encourage them to grow stronger. Cut out suckers below the soil level — these are the very tough, long branches that appear from the base of the rose bush or sometimes from the ground a few centimetres away. Spray these and the surrounding soil with lime sulphur to clean up pests and diseases.
• Fruit trees including apples, pears and cherries. Most deciduous fruit trees benefit from a structural prune in winter when you can see what you’re working with. The general rule is to reduce each branch by a third to a half. The other option is to shorten lateral branches only (those growing laterally from the main branches), leaving the main branches intact.
• Grapevines. If you are planting new grape vines or have inherited an overgrown “grapery”, it’s important to prune them in winter while they are fully dormant. The primary goal of pruning is to maximise the amount of one-year-old wood on each grapevine without encouraging the plant to produce too many grape clusters. Dense growth of wood causes them not to fully ripen because it produces relatively little “fruiting wood” each year due to poor air circulation and fungal diseases. Expect to remove 70 to 90 percent of the previous year’s growth each winter.
• Citrus trees include lemon, orange, mandarin and different types of lime trees. Many citrus varieties are some of the best trees for pots, so it’s even more vital they receive a good prune during winter. But the timing has to be considered — you’ll need to “read” each tree to observe when they become dormant for a brief period. They will usually finish fruiting before taking a break and getting ready to flower again — usually by the end of July or early August. Now is the time to prune! If you miss this critical timing, you may have to wait another year. However, you need to avoid over-pruning as you may sabotage the fruiting process next season. A good rule of thumb is to remove about 20 percent of the entire canopy, as most fruiting sites appear on the outer tree canopy. This leaves 80 per cent of the branches to grow next year, while still refreshing the tree and stimulating new growth.

Winter gardening mulching

While Brisbane’s winters are relatively mild, the occasional frosts can still occur. Protecting your plants from cooler nights (and days in some regions) can be done by adding compost and mulch to your garden. Mulching is key to insulating the soil, regulating the soil temperature and protecting plant roots from temperature fluctuations. Because it is rich in what your plants need to thrive, it also helps improve soil structure and water-holding capacity. Before laying your mulch, make sure you remove all weeds, and any grass within a 90 to 300-centimetre radius (depending on the size of your plants), and spread mulch inside this circle.

Spread it out evenly and leave a gap around the circumference of your tree or shrub so the mulch doesn’t directly touch the bark, as this will avoid collar rot. Avoid laying thick layers of organic mulch because this can prevent your plants from receiving enough oxygen and water and oxygen, and it will erode your soil’s pH.

When choosing mulch for your garden, organic mulch is ideal, and there are a range of types. Arborist wood chips known as forest mulch (a mix of wood, bark and leaves) are considered one of the best mulching materials overall, but you can also choose grass clippings (ensure it is aged prior to application), straw and many others, depending on what type of plants you are mulching. For example, native plants, flowers and vegetable gardens prefer certain types of mulches over others.

Water wisely in winter

Brisbane has a subtropical climate, so for us, winter marks the beginning of our dry season. During the winter months, we normally receive less rain, so it’s important to continue to water your gardens in winter. However, your watering schedule needs adjusting in the winter to suit cooler, drier temperatures. This often means reducing the frequency of watering, but providing deeper soakings to promote root growth. Water them deeply once a week, and be sure to water them early in the day so that any excess moisture can evaporate before nightfall. Avoid over-watering your plants and watering during the evening, as this can lead to moisture build-up and increase the risk of fungal diseases and root rot.

Monitor your soil’s moisture by using your index finger — poke it into the soil down to the second knuckle. If it feels dry, water, if it feels moist, hold off on watering for a few days and test again. Another more scientific approach is to invest in a soil moisture metre. These vary in price and sophistication from basic push-in-the-soil probes to permanently installed sensors, and they take much of the guesswork out of irrigation.

Winter weeding and feeding

Another tip for winter gardening is to get on top of weeds before spring comes, which will ensure you have a more manageable garden once the weather warms up. This can include weeding your lawn and garden beds, and pulling out any problem plants that appear between pavers and in concrete cracks.

In terms of fertilisers, it is important to feed the winter crops and flowers, because they are actively growing during this stage. However, when feeding these plants, it is highly recommended that you move away from a high-nitrogen feed to a low-nitrogen one. That way, you are promoting robust growth whilst reducing the risk of fungal diseases. A high-nitrogen fertiliser consists of high levels of nitrogen, sulphur and calcium. A low-nitrogen fertiliser contains a higher content of potassium and phosphorus but a small content of nitrogen. Talk to your local garden centre about winter garden tips that might be suitable for your garden.

Pest control during winter

While plant pests and diseases are generally less active in Brisbane during the winter, it’s still important to remain vigilant. Monitor your garden regularly and take immediate action at the first signs of pests and disease. Some of the more common pests during winter include:

• Aphids. The cabbage aphid and cotton aphid are two widespread species in Australia. Aphids feed on fruits, vegetables and ornamentals by sucking the fluid of phloem vessels. They can easily and rapidly reproduce. To get rid of them, you can use homemade garlic spray or systemic insecticides.
• Snails and Slugs. These pests can pose a huge threat to your garden. They can damage fruit, leaves, seeds and underground tubers, which can lead to major production losses. Snails thrive most in a moist environment. Handpick them and drop them in a bucket filled with salty or soapy water or spray them with copper oxychloride.
• Caterpillars. Small caterpillars love vegetables like cabbages and broccoli. Removing them by hand is your best option and deter through the use of garlic spray.
• Bronze Orange Bugs (Stink Bugs). These are considered a pest to all citrus trees. They appear in late winter as lime green nymphs, but as they grow, they turn an orange to bronze colour. When controlling these pests, you must be very careful since they emit a foul-smelling liquid that burns the eyes and skin on contact (we suggest you wear safety goggles and gloves). The most effective method of control is physical removal. Fill a bucket with water and detergent, gently shake the bugs off the branches into the bucket, and then safely dispose of the water.

What to plant over winter

Although many plants are resting in winter, others are ideal winter garden plants that will provide flowers, herbs and fruit.

Flowers

Although many plants are resting in winter, many are also ready to thrive, including flowering plants. In Queensland, these include:

• Ageratum. A classic garden annual that has small blooms that resemble tiny pom-poms! It also offers a rare colour in the flower world — blue — but can also be found in several shades of purple, pink and white.
• Carnation. This delicate and well-known fragrant plant has grass-like, blue-grey leaves that complement its perfectly shaped buttonhole flowers.
• Geranium. Also known as Pelargoniums, they are great perennial plants that require little attention once established. There are a variety of colours and leaf forms available, all suitable for pots, garden beds or hanging baskets.
• Impatiens. A member of the balsam family, Impatiens typically only grow to a height of about 30 centimetres. Great for pots, they also come in an incredible range of colours and patterns.
• Nasturtium. These pretty plants are easy to grow, edible, and a great companion plant. They are a wonderful addition to vegetable plots or anywhere you want a splash of colour.
• Wallflower. Wallflowers get their name from their original growth habit as they are often found growing on stone walls and rock faces, and they grow best in the winter.
• Zinnia. With vibrant daisy-like flowers in a rich rainbow of colour combinations, these showy drought-tolerant annuals will bring joy into your garden.

Herbs

Most herbs are fairly low-maintenance and easy to grow, even in winter. Add a little fresh flavour to your favourite receipts with these:

• Thyme. A kitchen garden staple, it’s easy to grow, virtually maintenance free, and makes an ideal drought-tolerant edible ground cover.
• Rosemary. Hardy, practical, versatile and delicious, rosemary ticks all the boxes and is another staple to have (fresh) on hand in the garden.
• Parsley. There are lots of varieties, but Italian flat leaf parsley is a modern favourite. Versatile in the kitchen, and easy to grow.
• Basil. Again, easy to grow, smells great, and a herb that is a must-have in your herb garden, especially if Italian food is your go-to.
• Mint. Mint looks great, is strongly aromatic and tastes great. This is another staple for your winter herb garden.

Veggies

In terms of winter vegetable gardening tips, a few veggies do really well in Brisbane in winter, including:

• Carrots. Can be grown year-round and withstand a variety of temperatures, including the cold. To get the best out of your carrots, don’t let the soil dry out and keep the soil moist for the first two weeks of germination. However, follow our above guidelines for watering, as generally, less is more in our subtropical climate.
• Spinach. Spinach is one of a few vegetables that will grow well over cold winter days, and it is fast-growing so you can begin picking outer leaves just a few weeks after planting. Spinach needs to be watered regularly if growing from seeds. Once seedlings begin to emerge, feed with an appropriate soil improver and plant food that feeds it above and below the ground. This will provide a balanced and sustainable growing environment for bigger, healthier crops.
• Brussels sprouts. Grow best in cool climates with cold, even frosty winters. This vegetable is the most cold-hardy of its brassica relatives which include broccoli, cabbage and kale. Sow seeds or plant seedlings in mid to late summer for a winter harvest.
• Silverbeet. Silverbeet is a long-lasting and highly productive vegetable. It grows year-round and is both cold and heat-tolerant. In warm northern climates, it can be sown almost all year.

Need help with pruning over winter to get ready for summer? Contact us for a free quote.

References

• Young H (6 June 2024) ‘How to take care of a winter garden when it gets cold’, Homes to Love blog, accessed 21 June 2024.
• Jim’s Mowing (2024) ‘Winter gardening tips’, Jim’s Mowing blog, accessed 21 June 2024.
• Brisbane Soils & Landscaping Supplies (26 June 2023) ‘The Ultimate Guide to Winter Gardening in Brisbane’, Brisbane Soils & Landscape Supplies blog, accessed 21 June 2024.
• Living Smart (12 July 2021) ‘July Seasonal Gardening Tips – Subtropical Queensland’, Living Smart blog, accessed 21 June 2024.
• Jim’s Mowing (June 2024) ‘Most Common Garden Pests In Winter’, Jim’s Mowing blog, accessed 22 June 2024.
• Aumann’s (June 2024), ‘Gardening All Year Round: What to Plant in Winter’, Aumann’s blog, accessed 22 June 2024.