Prune Fijian hibiscus now that the risk of frost has gone, as flowering happens on new growth. Sprinkle basalt rock dust around their roots for a mineral boost, and they'll be away. Every couple of years I prune our hibiscus hedge hard back to thick stems to encourage lush new foliage. Flowering will occur later in the season, but the hedge will be much easier to clip the following year. The trimmings are spread underneath the hibiscus, helping feed the soil as the leaves break down.
Prune straggly tall salvias if you haven't already, down by at least of the previous year's growth. Cut out spindly stems and old wood entirely.
Prune mophead hydrangeas if you didn't in autumn. Cut last year's flowering stems hard back to fat buds. Cut new stems back a third - these will produce this year's flowers.
Retaining Water
Soil moisture levels are already low for this time of year, so take measures now to prevent the "big dry" in summer at your place. Start by mulching well around fruit trees, shrubs, perennials and flower gardens to keep the soil moist as we head towards summer, reducing the need to water.
As mulch is broken down, it keeps the soil ecosystem kicking and your plants healthy. Arborists can supply bulk truck loads of mulch, so it makes sense to share with a neighbour.
Now is also a perfect time to put in some rainbarrels or a tank.
One year's seeding makes seven years weeding
Tackle weeding now, as it is much less tiresome when the soil is soft and they're easy to dig out. You'll also be removing the weeds before they seed.
Weeds are a good addition to the compost. If yours are seeding already, put noxious weeds in a garden refuse bin. Put less troublesome weeds in a barrel of rainwater and allow to rot instead. The resulting slurry can be poured on the soil as a fertiliser in around 6 months. Use this technique for Kahili ginger.
Rampant grass weeds such as kikuyu and couch are best allowed to dry completely. Fill a large bag (old wool bales are good) and leave in a dry spot under trees, then use the resulting "hay" as a dry, carbonous layer in the compost.
Fleshy Tradescantia makes good compost, too. Get the rotting process started by pouring on some boiling water to break cell walls, then add this nitrogenous layer to your compost, and cover.
Nourish and protect
Get the garden off to a good start by topdressing the soil with compost or a balanced organic fertiliser to support active plant growth in spring. Feed new plants with diluted liquid seaweed. Avoid over-application of nitrogen as growth will get too leggy at the expense of flowers or fruit.
Sprinkle Neem granules and lightly cultivate into the soil around pest-prone plants. Neem reduces the ability of pests to reproduce.
This month's flower
Cerinthe, also known as Honeywort, is an Old World flower whose native distribution encircles the Mediterranean. Cerinthe's foliage is as much a feature as the flower. The plant adds depth and mystery to the garden, with mottled blue-green leaves and purple, bruise-coloured flowers in the shape of small tubular bells which hang from the tip of the stems. The bees love it, which is not surprising given it is from the Boraginaceae family, of which comfrey and borage are members. Cerinthe grows quickly in early spring and it has done its thing by summer. It self-seeds via "exploding" capsules, so although short-lived, it behaves almost like a perennial, popping up in the same location again the following year.
