Gardening in Waitaki June 28th 2025

Into Another Month, and another stop-start week with King’s Birthday weekend upon us. June marks the time when many gardeners begin to pull back and tuck their gardens in for winter. Once the spent summer growth has been cut back, it's a great idea to add mulch to help insulate the soil and protect plant roots from winter chills. Drainage Check-Up: Recent rainfall has highlighted any poorly draining spots in the garden. If you’ve noticed plants struggling in soggy soil, dig them up and work on improving the site. Often, the issue lies with compacted clay beneath the topsoil. Dig deep down to the clay layer, break it up thoroughly, sprinkle gypsum over it, and add stones or at least three shovels of gravel to create a sump for water drainage. Replant, and your plant should thrive without risk of root rot. Root Cuttings – A Winter Project: This week, I’ve taken root cuttings of Hydrangea paniculata and a few other tricky-to-strike plants. If you’ve had trouble propagating some of your favourites, root cuttings might be the solution. They’re one of the most reliable and cost-effective ways to multiply many perennial and woody plants, especially during the dormant season from June to September. Woody Plants: Keep in mind that many trees are grafted onto different rootstocks, so only take cuttings from non-grafted trees and shrubs. Shrubs: Carefully remove soil from one side of the plant near the base to find healthy, pencil-thick roots. Take 2–6 inch (5–15 cm) root sections and cut them into 2–3 inch (5–7.5 cm) pieces. Use a flat cut on the top and a slanted cut on the bottom to keep track of orientation. Plant the cuttings in a deep pot, raised bed, or directly in a frost-free spot in the garden. Add a little sand to the bottom of each hole and dust the bottom ends with powdered sulfur to help prevent fungal issues. Cover with coarse river sand or fine gravel, and water only when the soil is dry. Perennials: It's often easier to lift the entire plant and select thick, fleshy roots. Take cuttings as above, replant the parent, and water it in well. In 3–4 weeks, cuttings should develop roots, and some may begin to shoot. Once shoots appear, feed with a half-strength liquid fertilizer. Transplant when established. Plants Suitable for Root Cuttings Include: Crabapple, Figs, Hydrangeas, Lilacs, Mock Orange, Poplar, Pussy Willow, Red & Yellow Twig Dogwoods, Old Roses, Snowball Bush, Weeping Willow, Yucca, Aster, Bear’s Breeches, Tall Phlox, Geranium, Globe Thistle, Hollyhocks, Horseradish, Oriental Poppy, Primrose, Rhubarb, Sage, Sea Holly, Perennial Statice, Raspberry, and Blackberry. Winter Garden Maintenance: remove all old hellebore leaves, as the undersides may be harbouring overwintering greenfly. New foliage will soon emerge as the flowers appear in mid-winter. Roses: Clean up all fallen leaves beneath bushes to reduce pest and disease risk. Apply a clean-up spray of lime sulphur to defoliate and treat scale, mites, moss, and lichen. Later in July, after pruning, follow up with a spray of Champion Copper and Conqueror Oil. This timing is ideal as bees, butterflies, and ladybirds are largely absent. Lily Bulbs: Continue planting in raised beds. Don’t allow roots to dry out. Gladioli: Begin early plantings now for blooms in November. Polyanthus: Brighten your garden or entryway with polyanthus in pots or beds. Veggies & Fruit: Coastal areas: Sow broad beans, garlic, shallots, and rhubarb. Colder inland regions: Best to wait—very little can be planted now: Fruit trees & deciduous trees with lichen: Apply a lime sulphur spray to clean them up—but skip apricot trees, as lime sulphur will burn their fruit buds. Cheers, Linda.