Gardening in Waitaki August 11th 2026

Wow, what a polar blast we've had this week! North Otago escaped relatively lightly compared with many other parts of Otago. August is always an unpredictable month for gardeners. Just when the soil begins to warm, and spring seems within reach, winter often has one last icy reminder. Even so, each day brings fresh signs of the changing season, with snowdrops, jonquils, early blossom and magnolias bravely standing up to the cold. This is one of the best times to visit garden centres if you are thinking of planting camellias or rhododendrons. Most are now flowering, making it much easier to choose the colours that will complement your garden. Both perform best in semi-shade or areas protected from the hot afternoon sun. I know the cold does not encourage seed sowing, but if sown now in good light, up off the cold ground and protected under glass, you will get them to germinate and grow on for an early start for spring flowering. Seed trays I sowed three weeks ago under glass are showing the first stages of growth. To make expensive seed-raising mix go further, I fill trays with compost and sifted soil, then add a thin layer of seed-raising mix on top.  Roses will benefit from feeding if you haven't already done so because roots are moving and buds are swelling. Aged manure is perfect, slow-release fertilisers are also a good food choice, providing nutrients over many months and help to keep plants healthy and vigorous. This is the time to plant the roses now on offer in Garden centers. Peonies and gladioli can also be planted now, along with Lilies, but those being lifted should be replanted immediately, as their bulbs never truly become dormant and dislike drying out.  Lavenders beginning to show fresh growth can be trimmed now. Older woody bushes can be cut back by about half to encourage fresh shoots lower down, while younger plants need only a light clip. A sprinkle of lime around the base will help maintain the sweet soil lavenders enjoy. If an old lavender has struggled for several seasons, replacing it may be the better option. Hydrangeas are also showing new shoots near the base, signalling that pruning can begin. Remove the stems that flowered last summer back to the second healthy bud from the bottom, leaving the remaining younger stems to produce next season's blooms. Remember, pink hydrangeas prefer alkaline soils while blue varieties require acidic conditions. If your blue hydrangea insists on turning pink, growing it in a large container filled with acidic potting mix is often the most reliable solution. Many climbers are already carrying flower buds, so trim carefully. Hardenbergia (Happy Wanderer) can be cut back after flowering, while jasmine that has been touched by frost is best left until warmer weather confirms which stems have survived. There is still time to divide established hostas before they come into full growth. Lift mature clumps, divide them into several healthy pieces with a sharp spade, and replant immediately. Hostas also make excellent container plants, but remember that emerging leaves are irresistible to slugs, so protect them early with prickly twiggy prunings. Comfrey is one of the garden's most valuable plants. Its deep roots draw nutrients from well below the soil surface and store them in the leaves. Pack chopped leaves into a lidded container and leave them to break down into a dark liquid. Diluted with water, it becomes a nutrient-rich feed high in potassium, ideal for flowering plants, tomatoes and other fruiting crops. Plant comfrey where it has room to spread, as it can become quite vigorous.  Lawns often show patches of moss at this time of year. While products containing sulphate of iron will blacken and kill moss, lasting success depends on correcting the cause. Poor drainage, soil compaction, excessive shade, acidic soil, mowing too closely, or poor fertility can all encourage moss to thrive. Healthy, well-fed lawns that are aerated and mown correctly rarely have serious moss problems. Plan your first spring lawn feed just before steady rain. Vegetable gardens deserve attention now. Dig compost into empty beds and allow the soil to settle before planting. If you're not using a bed immediately, sow a green crop such as mustard, oats, lupins, barley or wheat to improve soil structure and organic matter. Dig these crops in while still soft and leafy, before they become coarse and stemmy. Existing asparagus beds should be carefully cultivated without damaging the crowns, while new beds benefit from deep cultivation and plenty of compost. Sprouted potatoes can be planted now for an early crop, and winter cauliflower can be protected from frost by tying the outer leaves over the developing heads. Fruit trees and berry bushes are preparing for another busy season. A dressing of potash will encourage better flowering and fruiting, while a thorough watering followed by a generous mulch will help conserve moisture as growth accelerates. Cheers, Linda.