What to do in the garden this week
Prune and plant roses
There’s still time to prune your roses. Repeat-flowering roses (as opposed to those that flower once) should be pruned in late winter. It’s virtually impossible to kill a rose by pruning it so don’t be timid.
Aim to reduce the height of your roses by around 1⁄3-1⁄2. When making pruning cuts, make a sloping cut that starts about 1⁄2cm above the bud and slopes back. This is done to stop water collecting on the cut. Next, saw off any crossing stems and any damaged or diseased wood. Prune to open up the centre of the plant for ventilation and to prevent disease. Turn some of your prunings into cuttings. Just poke them in around the dripline of the mother rose, in a corner of a vege bed or a pot. A few days after pruning, apply a copper and oil winter clean up spray. If your rose has a bad scale problem, apply lime sulphur.
Garden centres are full of new roses, so why not plant one. Choose a spot that gets sun for at least half a day. Newly purchased roses require only a very light prune to remove diseased or damaged wood.
Spring is coming
Wild wintery weather swept the country last week but we gardeners can see signs everywhere that spring is on the horizon, and so we know it’s not too soon to start our summer crops!
You can sow trays of tomatoes, chillies, capsicums and eggplants now, but of course keep them inside your warm house or in a heated tunnelhouse until it’s warm enough to shift them into the garden – which in most of the country is no earlier than October.
Ideally keep your seed trays on something warm like a seedling heat pad, on top of the fridge, or a cosy spot with underfloor heating – bottom heat will hugely improve the strike rate – we all appreciate an electric blanket at this time of year!
Once the seedlings appear, they will need plenty of sunlight and warmth to keep them growing strongly as you want them to be as big as possible before you plant them outside.
The bigger the plants are when transplanted, the faster they will flower and set fruit, and you might be harvesting by January (and cherry tomatoes even sooner) rather than having to wait until February or March.
Plant asparagus crowns or sow seed
Asparagus needs both time and space, taking two years to crop if you start with crowns (and three if you start from seed) and requiring a dedicated bed. And given you need at least 10 plants for a decent harvest, with 40cm between each plant, that can take up quite a bit of real estate. But it’s pretty easy to grow, and produces for 20-plus years, so it’s worth starting now if you have room.
Dormant crowns are available from the garden centre this month, or sow seed in deep trays to plant out a year from now. And if you sensibly did this job a few years ago, you might be picking asparagus as soon as late August or early September.
Take hardwood cuttings
This method works for deciduous shrubs, fruit and ornamental trees, berries, roses and climbers. They are the easiest cuttings of all to strike as being dormant without leaves they don’t need the humidity and watering that leafy softwood cuttings do.
Grapes, figs and mulberries are almost foolproof to start with.
Start by selecting fresh, healthy growth. Cut the base of the cutting close under a node, leaf bud or branch union as this is where the most vascular tissue is. If you can pull the cutting off an attaching branch to get a heel, even better. Using sloping cuts above a node or bud at the top and a straight cut at the bottom below a node takes the guesswork out of ensuring the cutting is planted the right way. Wounding the base of a cutting by removing a slice of bark exposes a larger part of the cambium layer where the cells will grow into roots. You can dip the base of the cutting into a rooting hormone powder or make your own with willow water.
Poke 2⁄3 of the cutting into the dirt, leaving 1⁄3 exposed – making sure you plant it the right way up.
To prevent your cutting from drying out, tie a plastic bag over the pot. However, you also want to keep the top cool so that energy goes into forming roots rather than leaves. To warm the soil but not the air, you can buy horticultural heat mats or improvise with a pet bed warmer or similar gadget (but for safety remember that water and electricity are dangerous bedfellows). Then wait. You probably won’t see much action until spring.