Gareth Carter: Plenty of garden activity for January despite the rain

January is a good month to take cuttings of many plants. Photo / Supplied

Another week with rain in Whanganui — will summer ever come?

The rain throughout spring and into the summer months has, however, been phenomenal for plant growth. Looking at the trees in some of our parks and streets, the amount of growth that has been put on this year is extraordinary. Those who made new plantings of trees or shrubs in the past 12 months have timed it lucky.

What this shows us is the benefit of keeping plants moist and watered during warm periods.

During intermittent days of hot sun and wind, irrigation is still needed frequently, for pots in particular. It is good garden practice to water in the early morning. For vegetables such as tomatoes, it is better that plants go through the night dry if possible becauses this will minimise the spread of fungus diseases such as mildews, brown rot and black spot.

It is better to achieve a thorough drenching of one area rather than try to water the whole garden lightly. Try to direct the water at the soil where the roots are rather than over the whole plant.

We are very lucky to have an ample supply of water in Whanganui. Additional bores that were drilled some years ago are an asset for gardeners. We have not had summer watering restrictions for years now, enabling us to water with sprinklers every evening and morning if necessary.

Mulching is a good gardening practice to conserve moisture as well. This has the added benefit of adding organic matter to the soil. Plants such as our New Zealand natives, azaleas, rhododendrons, camellias, daphnes, kalmias, magnolias, clematis and liliums are just a few of the plants that enjoy a cool root run and good organic mulch or compost around the base.

There are several product options available to mulch with.

Tui Feeding Mulch is a popular choice and highly recommended; it is formulated to fertilise, hold moisture and improve soil structure.

Purchasing pea straw bales and spreading them over the garden is an economical option. I have spread bark chips over one of my gardens and this has been very successful for moisture retention and weed suppression. It looks attractive too.

Mulch from arborists’ chippers is good too, particularly once it has broken down a bit and is not so fresh. Fresh mulch can cause a nitrogen drawdown from the plants.

Lawns

The regular rainfall is also keeping the lawns lush and green, so no rest from the mower yet.

With the lawns in reasonably good health from regular rainfall, this is a good opportunity to do some weed control. Broadleaf-type weeds are easy to control with a selective spray application such as Yates Turfix or Weed n Feed.

Grass species are more problematic. Any creep of unwanted grass weeds is best dealt with swiftly while small, with an application of Roundup or another weedkiller directed onto the weed to minimise the risk of killing the desirable grass. Some use an artist’s small paintbrush to apply.

Growing your own plants from cuttings

January is a good month to take cuttings of many plants, including hydrangeas, buxus, houseplants and carnations. If you are successful, it can be most rewarding.

It is not difficult and if you have never taken cuttings before you may like to have a go. Here are some how-to-do-it tips:

• Choose strong healthy shoots. The cutting should have about 2-4 pairs of fully developed leaves and should be severed from the plant with a sharp knife or secateurs. Do not pull it off because this may damage the stem of the plant on which it was growing.
• The bottom of the cutting should be trimmed so it is just below a leaf or leaf scar and always with a very sharp knife. The lower leaf or leaves should be removed and if the foliage is excessive some of it can be trimmed off or back by up to one-half along the length of the leaf to prevent excessive loss of moisture.
• To increase the area where cell division and root development can take place, a wound about 1cm in length should be cut along the side of the cutting near its base. Dip the cuttings into a rooting hormone. There are a couple of different types depending on the type of plant. These will help stimulate cell division and root development. Keep your cutting material moist at all times. There are gel-type rooting hormones: Yates Clonex Red for hardwood cuttings, Yates Clonex Purple for softwood and semi-hardwood cuttings or IBAdex Powdered Rooting Hormone.
• Insert the cuttings into a “sharp” media such as propagation sand or, even better, in a specialist “cutting mix”. Daltons Premium Cutting Mix is a well-proven commercial mix used for the fast establishment of cuttings. It contains clean, screened 3mm pumice and fine-grade coco fibre, and balances moisture retention, soil aeration and drainage properties. The free-draining properties reduce the risk of soil-borne diseases.
• Set the cuttings in a tray or a pot with mix about 10cm deep, make a hole with a pencil or similar and space the cuttings about 5cm apart. Gently water to settle in the cuttings and place them in a shady spot. Place under a plastic cover that is sealed to prevent moisture loss but allows good light.
• Check watering requirements daily. After about four weeks the cuttings should start to root. When the roots can be seen coming out of the pot’s drainage holes it is time to transplant them to a bigger pot using a potting mix with fertiliser added.

Many houseplants can be multiplied by trimming just below a leaf node as described above and then sitting them in a jar or glass of water inside for two to three weeks. Changing the water weekly will stop you from having a green stagnant swamp in your house. Some house plants, such as rex begonias, will produce roots just from a section of their leaf set into a cutting mix. Once roots have started to appear, the new plants can be carefully transferred into individual pots with a suitable potting mix such as Tui Indoor Plant Mix.

It is very satisfying growing new plants from cuttings so why not experiment and have a go.

For more gardening information go to www.springvalegardencentre.co.nz

– Gareth Carter is general manager of Springvale Garden Centre