Garden Work for June

New Zealand Journal of Agriculture, Volume 100, Issue 5, 16 May 1960, Page 509

Garden Work for June

By

JOY WATKINS,

Horticultural Advisory Officer, Department of Agriculture, Auckland

Camellias are in flower now and are most useful for cutting. The earliest to flower are the sasanquas. They are free flowering with single blooms,

and the plants do well in most parts of the country and on most acid soils. Later in June the many beautiful named varieties of C- japonica and C. reticulata start to flower. Those of C. reticulata have the largest flowers, and their characteristic dropping of their blooms as soon as they begin to fade is a useful habit, but they are the most difficult type to grow. The winter-flowering heaths are colouring up, Calluna H. E. Beale and Springwood white, Erica carnea King George and Winter Gem, being particularly good varieties. Both heaths and camellias require a lime-free soil and cool, moist conditions for maximum growth. They thrive in partial shade, the heaths being useful as ground covers under other shrubs, for example, rhododendrons, while they all appreciate an annual topdressing of leaf mould. Many proteas are flowering in the milder parts of the country. These make handsome and unusual cut flowers, though their nectar attracts ants and can damage furniture on which it may drop. The flower stems should be cut so that a few leaves remain on them to provide buds for next year’s crop of flowers. If cut back into bare wood, the stem is unlikely to sprout again

and will probably die back. Judicious cutting of the flowers is usually sufficient pruning for these shrubs. Daphne odora does well in the north and D. genkwa and D. mezereum in the south. Most daphnes suffer from a virus disease which causes a yellowing of the leaves. Badly affected bushes should be destroyed. Particularly on heavy clay soils, they live for only about seven years. For this reason, it is desirable to raise replacements from healthy plants at intervals. D. mezereum can be raised from seed, while the other species may be struck from layers or from cuttings taken of the tips of side branches in autumn.

In frost-free districts luculia, Podalyria sericea, eriostemon, and reinwardtia add to the colour and scent in the garden. As the days shorten, there is less growth of plants in the garden. Vacant ground should be dug over and weeds removed or buried, compost, leaf mould, or manure being incorporated at the same time. Lime is required by a few ornamental plants such as anemones, scabious, gypsophila, lavender, and carnations, and where new beds are being prepared for any of these flowers agricultural lime at about 1 lb to the square yard (if the soil is very acid) or proportionately should be

spread on the surface after digging so that the winter rains will wash it into the soil. Lime can also be applied to the soil around established plants, if this has not already been done. Lime must not be applied to camellia, rhododendron, azalea, heath, and similar acid-loving plants; otherwise the leaves will turn yellow and the plant may die. Pruning Many deciduous trees and shrubs can now be pruned, as the leaves have dropped and the plants are dormant. Those which produce flowers during winter and early spring should be left until they have finished flowering. Many shrubs and trees require only light pruning to maintain the shape of the plant. Dead, diseased, or weak crowded branches should be cut away at the same time. Where two branches cross and rub, one should be removed to allow the other to develop properly. Ornamental trees which have grown too tall can be headed back by cutting the main stems back to side branches at a suitable height. They should not have all upright stems sawn off level to the same height, regardless of whether there is a side shoot or not, as a bare stump will either die back or it will produce a ring of new upright branches in the following season. By cutting to a side branch, the flow of sap in the spring is diverted along this branch. As wistaria flowers at the base of growth made during the last season, this growth should now be cut back to a bud within a few inches of the old wood, so that the flowers will not be hidden by leaves and branches.

Shrubs which are frost tender, for example, poinsettia, luculia, and bougainvillea,' should not be pruned until danger of frost is past. Roses can be pruned between the middle of June and the end of August, the end of August being preferable where there is any likelihood of frost damage. Those which are left until August should have any very long stems shortened, as these are likely to catch the wind and cause the bush to rock backward and forward. In a light soil the roots are loosened in this way. In a clay soil a funnel forms round the base of the stem and water collects, causing damage or death of the plant. Where gardens are exposed to strong winds every effort should be made to provide adequate shelter. Where a solid wooden or metal fence is impracticable, alternatives are hedges or open fences or trellis with strong climbing plants growing through them. The ground must be well prepared for either climbing or hedge plants, by digging deeply, incorporating leaf mould or compost, removing weeds, and possibly also providing drainage. Drains should not be placed near hedges, as the roots grow into them and block them. Rock or scoria drains would be more suitable. Once the plants are established little can be done to improve the drainage; yet poor drainage is one of the most frequent causes of the death of hedge plants. On a heavy, badly drained soil many of the roots may be killed by prolonged spells under water. Soil-borne diseases such as phytophthora and fusarium can then gain easy entry into the damaged root system, causing root rotting or collar rotting, which is usually fatal. The first sign may be a yellowing of the leaves, lack of growth, and dieback of the branch tips. This is the direct result of root injury, as a damaged root system is unable to absorb sufficient water and minerals to supply the leaves and branches. Any plants which have died in this way should be removed and the ground treated with copper oxychloride at 1 lb to 5 sq. yd. before replanting. If the drainage can be improved in any way, for example by digging a drain on a lower level near the hedge, this should be done. Some of the best hedge plants are slow growing, and it may be an advantage to grow a row of tree lupin or brush wattle (Albizzia lophantha) on the windward side, being removed when the hedge is sufficiently established. The ground should be prepared now, ready for sowing in October. Continue planting trees and shrubs, staking and tying where necessary. Herbaceous Perennials Stems of herbaceous perennials have died back and can be cut off at ground level and burnt or composted. The

ground between the plants should be forked over carefully to remove weeds, let in the air, and allow winter rains to drain freely through the soil. Care should be taken to avoid damaging the buds and surface roots. Rock Garden In the rock garden remove any dead leaves which may have collected in or on the plants, as these can cause rotting, apart from harbouring slugs. Plants with woolly leaves are particularly liable to rot, and these should have perfectly drained sites prepared for them before planting, the choicer species being protected during winter by a sheet of glass. Floral Arrangements Poinsettias and Iceland poppies must be seared before being placed in deep water overnight to harden. Searing consists of holding the end of each stem over a flame for 15 seconds to disperse the milky juice which will otherwise congeal and prevent the absorption of water. Only fully developed violets should be picked, as buds will not open in water. Violets left out of water for a while can be revived by immersing them completely in water for an hour or so before arranging. Few people have the patience to arrange such

small flowers individually and violets are most easily used tied in small bunches which are readily fixed in moss or wire netting or on a pinholder. In this way they make a bold mass of colour which can form the focal point of the design. Foliage plants come into their own during winter to provide a setting for a few flowers or an independent decoration. As an independent decoration cut foliage can be used or pot plants can be grouped in a container. Of the large range of winter-flower-ing shrubs which can be grown in New Zealand many have distinctive individual flowers, such as protea, phylica, dryandra, and banksia; others produce sprays of tiny flowers, particularly in shades of cream, pink, and red, for example manuka, thryptomene, calythrix, and hypocalymma. It is essential to slit or bruise the stems of all cut shrubs and to place in deep water in a cool, dark place overnight before arranging; otherwise many branches will not take up water quickly enough when placed in a warm room and the flowers will soon wilt and die. Shrub flowers should be cut with a sharp knife or secateurs to just above a bud, being careful to maintain the shape of the bush.