The Flower Garden in January

New Zealand Journal of Agriculture, Volume 73, Issue 6, 16 December 1946, Page 601

The Flower Garden in January

By

J. P. HUDSON,

Horticulturist, Wellington.

LITTLE planting is done in flower gardens in January, as dry, hot weather makes conditions difficult for new plants to establish themselves. There is, however, plenty to be done to maintain a bright display of flowers for the late summer and autumn, and cuttings of many flowering , plants taken now will root rapidly in a cold frame and produce good plants to flower next year.

Biennials, such as' wallflowers, Canterbury bells, hollyhocks, for-get-me-nots, and sweet Williams, may now be sown in the warmer districts in a part of the garden where they will not be in full sun. When the seedlings . are large enough to be handled they should be pricked out a few inches apart in a nursery bed to make bushy, well-rooted plants to put out later into the beds where they will flower next year. Christmas lilies (.Lilium candidum) can best be moved as soon as the old flowering stem has turned yellow and the leaves have withered. At this season the bulb is almost dormant, but soon starts to root again and send up a new rosette of leaves, after which these lilies can be moved only at the risk of losing next season’s flower spike. The nose of the bulb should be planted not deeper, than 2in. below the surface. Christmas lilies can be increased rapidly, by . detaching scales from the . bulbs and - inserting ■ them upright in , boxes of sandy soil, with the tip of each scale just below the surface. Keep the boxes moist, preferably in a cold frame, and plant the scales out when >they have' rooted. Plants produced in this way should flower in the second season after planting.

Flowers which have faded should be picked off regularly to prevent them from going to seed, as seed formation often leaves plants with insufficient energy to form further flowers. This applies especially to annuals, the flowering life of which can be considerably extended if dead flower heads are picked off regularly. Gaillardias should be grown in every garden, as they bloom freely«and make a bright show, especially in hot-, dry weather, and in poor or sandy soils where few flowers will flourish. Seed can be sown now and the seedlings later planted out into the borders in warm, well-drained, sunny places where they, will flower next spring. On heavy, rich soil they do not always winter successfully, and .. in such places they are best raised by sowing the seeds in boxes in spring and planting the seedlings out in October. An interesting method of, multiplying gaillardias is to dig up '. plants in the autumn and cut the fleshy roots into pieces Ij to 2in. long, making sure that the

end of each root cutting which .was nearest the crown is cut off square and the other end with a slanting cut. Put the cuttings upright and 2in. apart in sandy soil with the square end just below the level of the soil. By spring each root cutting will have produced roots and buds and can then be planted out in the usual way. . Iceland poppies: Experience in Wellington Province has shown that: there is no advantage in planting out Iceland poppies until . the end of February or March, as earlier plantings may become , very heavily infected with spotted wilt virus disease. Commercial beds planted earlier than this have been known to show such a high infection that they were ploughed in as useless. Seed should be sown in January in boxes which should' be kept in a shaded position, covered with paper, and moistened when necessary until the seedlings show, when the paper should be removed. When the seedlings are large enough to be handled they should be pricked out into boxes and later planted in a well-limed bed which should not have been newly manured. This late planting will produce strong plants which will flower well late in the . winter and next spring. Peonies and pyrethrums become Relatively dormant for a time after flowering. If they are becoming overcrowded, or more plants are required, the clumps can be split up and replanted in January ,or February. The newly-planted crowns must be watered freely in dry. weather until they have formed a strong root system. Peony roots are fleshy and should not be injured more than necessary when they are divided. Tree peonies, which resent being transplanted, are. propagated by grafting and not by dividing their roots.

Propagation of flowering shrubs is an important item in January’s work, Budding of roses can continue as long as the bark on the stocks lifts freely, Layer rhododendrons by bringing down each suitable branch and burying it in a trench in such a way that the tip projects above ground l and the branch is bent sharply to form an elbow a few inches below the surface. On the sharpness of l this elbow, which checks the flow of sap, the successful rooting of the layer depends.

The. layer should be rooted and ready to separate from the parent in 1 to 2 years, depending on the climate. It. is better to bury the branch in a trench than under a mound of soil, as a mound dries out too easily and requires watering. Cuttings of new' side shoots, each a few inches long and cut off with , a small heel of older wood, should be taken as soon as they are long enough from Buddleja (Buddleia alternifolia), mock orange (Philadelphus spp. ), Deutzias, Forsythias, Diervilla (Weigela) spp., and many other flowering shrubs. 'The cuttings must be prevented from flagging, and are therefore best inserted in a frame or propagating pit, where the atmosphere can be kept moist until the cuttings have formed roots. A gritty, open soil containing plenty of sand is best for striking cuttings. Silty soils which “run” and form a crust on the top when they are watered are useless for propagating.

Pruning of shrubs which have flowered on last year’s shoots should be attended to as soon as the flowers fade by removing as many as possible of the shoots which have borne flowers this 1 year. That ensures that plenty of vigorous shoots are produced to flower next year. In the case of shrubs

which flower in summer, it is 7 not usually practicable I to cut off all the flowering shoots (as is advised for the spring-flowering jessamine, for instance), as one or two strong new shoots are likely already to have grown on some of the branches which have flowered. These new shoots may. be required to keep the bush shapely and well furnished with new wood and should not be removed. Dier- ■ villa (Weigela) spp., Deutzias, and mock orange are shrubs which should be pruned in this way as soon as the flowers have faded. .Hydrangeas root readily from cuttings taken from the end • of new - shoots, trimmed off with a sharp ..knife just below the bottom bud, then inserted in a ' cold frame and watered in. Cover the cuttings, with a sheet of newspaper for a few days to shade

them from the sun, and keep the atmosphere moist. Most propagators .cut off the bottom two leaves close to the stem and also cut off about half of ' the /leaves which remain. Sawdust is proving a valuable form of mulch to apply to the soil in a layer several inches thick around rhododendrons, azaleas, and many other flowering shrubs, especially on heavy clay soil. Sawdust from Finns radiata (insignia') is preferred, as it' rots more quickly than other' types. Though some gardeners use it fresh, others prefer to leave it until it goes

brown before using it.,'lt is certainly less unsightly when it is darker in colour.. .

Seed saving . from home-grown flowers can add interest to home gardening, though the seeds will not necessarily produce . plants similar to their parents. As a general rule, especially . with uncommon alpine • plants, the seed pods should be collected as soon as they are ripe, put in trays for a few days to dry off completely, and ' then opened or crushed to' liberate the seeds. The chaff should then be separated as far as possible and the seeds sown at once; many seeds which will germinate, quickly ,if sown as soon as they are ripe will be slow in germinating if they are kept a month or two before being sown. By early sowing sturdy plants can be produced before the cold

weather sets in. Staking and tying dahlias, chrysanthemums, and other tall herbaceous perennials must not, be neglected. If large blooms are required for show purposes, all flower buds but one should be removed from each stem and the plants should be fed regularly either with a topdressing of complete fertiliser or, preferably, with dilute liquid manure. If the soil is dry they should also be watered regularly, as first-class blooms can be produced only by plants which have always had sufficient water at their roots.

Moreover, fopdressings of' fertiliser are of no. assistance to plants unless the materials are washed down into the soil and dissolved in’ the soil water. Reminders About Common Troubles Narcissus fly is a serious pest of narcissi and daffodils. The fly lays its eggs near the base of the dying leaves or in the hole which is left in the soil when the leaves die down. ,The young larvae work down to the bulbs, which they , enter through the baseb and then feed inside ' the bulbs,' which are ruined. Cultivating the soil to keep it close to the fading leaf bases, and to close up the holes left by the leaves when they die, does much to reduce the severity of an attack by making it difficult for the young larvae to reach the bulbs. When narcissi bulbs are lifted they should ■ never be left lying about on 1 , the soil or in trays outside, as that gives the flies an opportunity of laying their eggs directly on the bulbs. All bulbs which, feel soft should be burned; they probably contain larvae of the flies.

Rose mildew commonly attacks roses, especially ramblers, growing on the side of a house or in a position where air does not circulate freely round them. A reasonable control of this disease can. be obtained by .dusting the plants, with flowers of sulphur. An easy way of dusting is to enclose a handful of the flowers of sulphur in a piece of fine muslin, hold it near the plants, and tap the bundle smartly with a stick, when a cloud of the dust will be ejected. j .•

. Thrips, which arc slender, elongated insects up to l-10in. long and ranging from .yellow to brown or black in colour, often seriously attack gladioli. The adults are winged and fly freely, but in the younger stages the insects are wingless. The insect feeds by puncturing the leaves and petals to obtain the cell sap, and in doing so produces a characteristic silver or brown, scurfy appearance on the surface of the parts attacked. If the insects feed on the ’ flower . buds, these may look ‘’scorched” and the petals may be unnaturally streaked. Thrips are often carried over from season to season in the corms, which should be kept free from the pest while in storage by dusting them with naphthalene flakes. Careful search for thrips should be made on the developing leaves and flowers at frequent intervals during the growing season, or serious damage may be caused before it is noticed. Regular spraying with nicotine sulphate (black-leaf 40) will keep the pest in check and ensure that the blooms are not'disfigured by its attacks. (Nicotine sulphate spray is made up by dissolving 2oz. of soap in a little hot water and adding it, with 1 fluid ounce of nicotine sulphate, to 4 gallons of water.)