Weekend gardener: the great divide
Rhubarb
Divide rhubarb plants if they are too crowded or you wish to share it. This is best done every five years. Dig up a plant, and with a spade divide the rhizome – the part below the surface of the soil from which the stalks emerge. Ensure each part has a growing point.
Generally, inner rhizomes are less vigorous than outer ones. Any parts that look decaying, wizened or old can be discarded. If not replanting straight away, wrap in damp newspaper or cloth.
Rhubarb likes best full sun and fertile free-draining soil. Plant with the growing point just below the surface. Before planting dig in a hearty amount of compost.
General care involves removing flowering stalks to stop them weakening the plant. Spread a mulch of well-rotted organic matter around plants in spring to help retain soil moisture. Hot dry summers will inhibit growth.
Feed with a fertilisers or compost tea in spring and summer.
Edibles
Broad beans may be sown until the end of June (in all but the coldest districts). Sow about 4cm deep and about 20cm apart in blocks (to aid pollination and protect against wind damage).
Asian greens, beetroot, broccoli, burdock, carrot, endives, florence fennel, kohl rabi, lambs lettuce, leeks, lettuce (cool-weather types), onions, parsley, radish, rocket, shallots, silver beet, snow peas, spinach and turnips may also be sown direct in the garden.
As well, brussels sprouts, cabbage, cauliflower and kale seeds may be sown under glass for planting out later.
As a rule, most of the vegetable seedlings on sale at garden centres now will be suitable for planting out in the garden, though some may need to grow under cover. If in doubt, ask staff. Keep all newly planted seedlings well-watered.
Ornamentals
Primulas, primroses and polyanthus benefit from a small handful of blood and bone at planting.
Fertilise existing bulb beds with blood and bone, and plant new bulbs.
Take rose cuttings. Use shorter side stems with flower, pull off at join with the main stem and cut off flowers and all the leaves apart from the top two. Insert in a pot of potting mix and keep in shady spot for 12 months. Keep damp.
Prune dead, diseased or dying branches from climbing roses. Tie in new shoots and prune any side shoots that have flowered by about two-thirds. Any really old branches may be cut back to base.
Prune hedges without delay.