Summer Annuals for the Flower Garden

New Zealand Journal of Agriculture, Volume 89, Issue 5, 15 November 1954, Page 535

Summer Annuals for the Flower Garden

ANNUALS are among the easiest and most profitable plants to grow. Seed is cheap, easy to obtain, and not difficult to raise. Most annuals give a prolific flower crop, creating colourful garden effects, as well as providing ample flowers for cutting, especially during hot, dry summer weather. This article by M. Joanna Lockie, Horticultural Instructor, Department of Agriculture, Auckland, describes some of the uses of annuals.. The flower garden notes for December are by the same author.

ANNUALS are plants which normally complete their life in one year; they grow, flower, and set seed all within the year from sowing.

There are other plants which do not complete their whole life cycle in one year, but which it is convenient to treat as annuals because of their habits; perhaps they flower in the first year from sowing or they are frost tender. Antirrhinums, bonfire salvias, and pansies are examples. Antirrhinums are perennials, but in the second year of flowering the bushes are straggly, woody, and hardly worth garden space, and the same applies to bonfire salvias when they are left to grow on, though they are really shrubs.

There are cases, too, where an annual has been made to live longer than a year simply by not allowing it to set seed. Such a plant does not last long or make much of a display, but it shows how the removal of spent flower heads keeps the plant flowering.

Annuals can be used in innumerable ways. They cover a wide range of colours, and vary in height, habit, shape, and form. It is surprising that greater advantage is not taken of the scope they offer.

The routine annuals, stocks, poppies, zinnias, and asters, are common enough and are used freely for flowers for cutting as well as garden display.

Dwarf plants growing 6in. to Bin. high, for example, alyssum, linum, and Virginian stock, are ideal for growing as ground cover under shrubs, in the chinks between concrete blocks, or to cover up large expanses of newly dug land. Portulaca seed can be scattered over an area to go down in lawn, and will give a brilliant display. At the other extreme there are the annuals of 6ft. to Bft. high, such as sunflowers, Mexican sunflowers, lavatera, and Humea elegans (incense plant), which can be used to give height at the back of a border or to make a temporary screen.

To give privacy or shade two climbers can be used, Mina lobata (Quamoclit lobata) and morning glory (Ipomea tricolor) Heavenly Blue. They can be run up over a wire fence or trellis; sweet peas can be used for this too.

In the wetter portions of the garden forget-me-nots will quickly naturalise, and there are several floriferous varieties, which continue flowering into early summer, in deep and pale blue and pink, 'far removed from the shy flowering plant which grows along the banks of watercourses. Cinerarias and

Primula malacoides will soon naturalise in northern districts in damper areas of the garden, but in colder districts these will need to be transplanted every spring.

For hard, dry banks and borders portulaca, Livingstone daisies, ursinia, and dimorphotheca will all be perfectly happy.

Low-growing annuals will often grow in an exposed border where other plants will not. Newer or different kinds may be experimented with and grown in blocks or drifts. Group planting emphasises the individuality of the kind and drifts of annuals show up in the garden.

Some annuals which do better when sown in the positions in which they are to grow are larkspur, godetia, clarkia, mignonette, to mention a few, and it is possible to mingle drifts of these with shrub or bulb plantings.

The spider flower (Cleome spinosa) is well known now, with its pink heads and prominent stamens. When grown individually among other plants it has little effect, but it becomes a feature if it is grouped and six or more are in flower together.

Gilia, the Brazilian fire plant, is the same. It usually throws one tall spike about 3ft. clothed with delicate foliage and fine, red, tubular flowers. Individually, it is too fine and becomes lost among other plants, but a patch of them, planted about Bin. to Bin. apart, forming a light airy display of soft green and red, is really effective.

In favourable soils and mild climates group plantings may be left to reseed. This occurs readily with cleome, larkspurs, and nigella, perhaps because these plants seed easily and inconspicuously, without looking too untidy in the process.

TALLER PLANTS USED FOR BEDDING SCHEMES Habit of Flower colour growth Height Amaranthus caudatus Love-lies-bleeding Red . . . . Upright . . . . 2ft. to 3ft. Antirrhinum .. Tetra-snap types. . ■ ■ Snapdragons . Varied . . .. Upright . . 2ft. to 3ft. Aster . . . . Varied . . . . Upright .... .' 2ft. to 3ft. Calendula . . '.. .. Pot marigold. Radio,. Lemon . Queen . . Yellow and orange Bushy . . 2ft. Celosia plumosa . . Cockscomb . . Scarlet, yellow . . Upright . . 2ft. Oentaurea moschata . Sweet sultan .. Lavenders, pink, and yellow . . Upright . . 2ft. Cheiranthus cheiri . . Wallflower . . Yellow and bronze Bushy . . . Ift. to lift. Chrysanthemum coronarium . . Golden Glory .. Yellow and orange Bushy .. 3ft. to 4ft. Cleome spinosa . . Spider flower . . Pink . . . . Spreading . . 3ft. Cilia coronopifolia . . Red .... Upright . . 2ft. to 3ft. Cilia capitula .. Thimble flower . Blue .. .. Upright .. lift, to 2ft. Petunia. . . . . Ruffled types-..- Varied . . .. Spreading' .. lift, to 2ft. Salpiglossis ... ■ Purples and golds Upright ■ .. 2ft. to 3ft. Salvia farinacea .. Blue .. .. Bushy .. 2ft. to 3ft. Salvia patens .. Blue ... .. Bushy ■ .. 2ft. to 2ift. Salvia splendens .. Bonfire -.. Scarlet .. .. Bushy .. 2ft. to 3ft. Stock, Brompton . . Bushy • ■ .. - lift, to 2ft. Stock, 10-week . . Varied . . . . Bushy . . 2ft. to 2ift. Tagetes erecta .. African marigold Yellows and bronze Bushy .. 4ft. to sft. - Tagetes patula . . French marigold Yellows and bronze Bushy ■ • . . 3ft. to sft. Zinnia .. ... Giant mammoth Varied .. .. Upright . , 3ft. to 4ft,

TALLER PLANTS SUITABLE FOR GROUP OR NATURALISED PLANTINGS Habit of Flower colour growth Height Alonsoa warscewiczi Scarlet . . . . Bushy ... lift. to 2ft. Cineraria ... ... Mauves and pinks, varied . : Bushy. . . 2ft. Olarkia elegant ... Pinks and white . Upright . . 2ft. to 3ft. Cosmos ... . . Pinks and white, varied . . Bushy . . 3ft. to 6ft. Godetia ... . . . . . Reds and pinks . . Upright .. 2ft. to 3ft. Helichrysum . . Everlasting daisy Red, pink, and ' T . ■ yellow ... Upright . . 3ft. to 4ft. Humea elegans .. Incense plant . Deep red .. Upright .. 4ft. to sft. Ko chia trichophylla_ . Summer cypress Green to red - foliage . . Bushy . . 2ft. to 3ft. Larkspur . . . . Blue and pink . . Bushy . . 2ft. to 3ft. Lavatera ... . . Pink . . . . Bushy . . 2ft. to 3ft. Linaria . . . . Toad flax .. Varied .. . . Upright .. Ift. to 2ft. Mignonette . . . . Pale cream and green .. .. Bushy . . l|ft. to 2ft. Molucella laevis ... Shell flower. ' Green .. . . Bushy .. 2ft. to 3ft. Molucca balm Nicotiana .. ... Tobacco flowers Varied .. .. Upright .. 2ft. to 3ft. Nigella . . . . Love-in-a-mist . Blue . . . . Bushy . . 2ft. to 3ft. Scabiosa .. .. Pincushion .. Varied . . .. Bushy .. 3ft. to 4ft. Schizanthus . . Poor-man’s-orchid Varied . . . . Bushy . . 2ft. to 3ft. Sunflower .... Yellows . . . . Upright .1 4ft. to 6ft. Tithonia . . . . Mexican sunflower Orange . . . . Bushy . . sft. to 6ft. LOW-GROWING ANNUALS SUITABLE FOR EDGINGS OR MASSED PLANTINGS Habit of Flower colour growth Height Ageratum ... .. • Blue Ball .. Blue .. .. Compact, bushy to Bin. Blue Cap . . Compact, bushy Anchusa . . . . Blue Bird . . Blue . . . . Compact . . 15in. Antirrhinum ... Snapdragon, Tom Thumb varieties Yellow, white . . Compact, bushy 6in. to Bin. Alyssum maritimum . Little Dorrit .. White .. .. Compact, bushy 4in. Lilac Queen . . Mauve . . . . Bushy. . . 4in. Begonia semperflorens Fibrous-rooted begonia, Indian Maid . Bronze foliage, red flowers . . Upright . . Bin. Empel .. Light pink .. Upright .. 12in. tolBir. Centaurea cyanus .. Cornflower ... Blue, white, and pink . . . . Upright . . 12in. to 18in. Oentaurea moschata . Sweet sultan . . Pinks, mauve, and yellow . . Upright . . 18in. to 24in. Cheiranthus allioni . .Siberian wallflower .. Bright yellow .. Compact, bushy 12in. Cheiranthus cheiri . Wallflower . . Bronze and yellows Compact, bushy 18in. to 24in. Delphinium grandi- . florum .. ...... Blue'Butterfly . Deep blue .. Compact .. 18in. Dianthus chinensis . ' 1 . ■ heddewigi .. Japanese pink . Reds and pinks .. Upright .. 9in. Dianthus heddewigi Giants . . . . Fringed dianthus Reds . . . . Upright . . 9in. photheca aurantiaca . . Orange . . . . Upright . . 12in. Iberis . . . . Candytuft . . Pinks . and whites Upright . . 9in. Impatiens (frost tender) . . . . Balsam . . Pinks and white . Upright . . 18in. to 24in. Linum . . • • . . . . . . Red and various . Spreading . . Ift. to 2ft. Lobelia .. • . . Cambridge Blue Blue .. .. Compact .. Bin. Myosotis alpestris . . Forget-me-not . Dark blue . . Compact . . 6in. Mesembryanthemum . Livingstone daisy Varied . . .. Spreading .. 6in. Nasturtium . . Golden Gleam . Yellows, red, and golds . . . . . . . . . . 12in. Fire Gleam .. ■ Bushy .. 12in. Scarlet Gleam . ...... 12in. Nemesia compacta . . Blue Gem . . Blue , . . . Upright . . 9in. Nemesia strumosa .. Varied .. .. Upright . . 12in. N emophila insignit . Blue .. .. Spreading .. 9in. Pansies .. . . Varied .. .. Spreading .. 6in. Phacelia campanulata Blue . . . . Spreading . . 9in. Phlox drummondi . . Varied .. .. Spreading ..' 2in. to 18in. Portulaca . . . . Reds and yellows Spreading . . 6in. Petunia .. . . Single bedding . Varied .. .. Upright .. 12in. to 18in. Giants of California . . Veined throat .. Spreading .. 12in. to 18in. Silene armerxa . . Deep pink .. Bushy .. 12in Salvia . . . . Rongatea Gem . Scarlet . . . . Bushy . . 9in.' Sweet wivelsfleld . . Pinks . . . . Upright . . 18im Ursinia anthemoides . . Orange . . . . Upright . . 12im Verbena .. . . Reds, purples, . and , white .. .. Spreading . . Bin. to 12in. Viola . . .. Purple, yellow, and • . . . , ■ white . . . . Spreading . . 6in. Virginian stock . . Varied . . . . Upright . . 3in. to 4in. viscana . . . . Varied . . . . Erect . . . . 12in. Tagetes .. .. _ Yellows and bronze Bushy .. 9in. to 12in. Zinnig, , , . • Lilliput . . Varied, pinks and creams . . Bushy . . Bin. Magic Carpet . . Bronze and yellow Bushy . . Bin.

Forget-me-nots, primulas, and many other plants would seed readily if allowed to do so. Where the hoe is kept constantly moving through all borders there is little chance of any ripe seeds germinating, even if the seed heads are allowed to mature. Bedding Displays In contrast to the informal and group planting of annuals formal bedding designs may be used. One bed or border is set aside for annuals and they are planted with precision in rows. Very good results may be achieved. One variety may be used or a design worked out using two or more, kinds of plants; in such cases it is usual for taller plants to fill the centre or back of the bed and lower plants a border. Ideas for bedding specimens may be gained by watching effects in parks and reserves. The principal disadvantage is that the bed must be cleared after flowering and it looks rather bleak until the new plants have grown on. Preparation of Bed Beds for annuals should be worked up thoroughly to a good tilth. The soil can be improved by working in compost, decayed sawdust, seaweed, etc., but these materials should not be given too liberally unless they are thoroughly decomposed. A dressing of flower border fertiliser mixture made up of 3 parts of blood and bone, 2 parts of superphosphate, and 1 part of sulphate of potash may be given at 4oz. to the square yard. If too much raw organic matter is dug in, the plants may receive a check due to starvation through a shortage of nitrogen caused by a temporary unbalance of the work of the nitrifying bacteria in the soil. This may be alleviated by adding dried blood or sulphate of ammonia at 2oz. per square yard or blood and bone at 4oz. per square yard. Drainage should be good; waterlogged conditions may cause death of root hairs and slow up growth considerably. Wet soil, especially in early stages of plant growth, usually renders plants more susceptible to collar rot and other fungous attacks. If the soil is wet, it is better to plant later when conditions are better. Soil should not be worked up while it is too wet, as it is liable to remain in hard lumps, which does not improve the tilth. Planting Raising of seed in boxes and open beds is described fully in the June and July 1954 issues of the “Journal of Agriculture”. Seedlings should be vigorous and well grown. Starved seedlings showing yellow foliage and stunted growth, or lanky plants, do not really give results to justify the after-care they need. Healthy seedlings carry straight on to good growth and form better bushes and carry a greater amount of flower. When planting out is done ample room should be allowed, because if plants are too crowded, they compete for light, air, and food and become weak and drawn and more susceptible to disease. During planting, roots should not be allowed to dry out. A handy guide

for planting distance is the length of the trowel or its handle, which is about Bin.

The planting hole should be large enough to take the roots without cramping them. . A trowel should be used for planting. Spindly annuals such as zinnias and antirrhinums may be set a little lower in the ground than they were in the seed box, but the heart or growing tip of a plant which grows in a rosette, for example, nemesia and forget-me-not, should not be covered with soil. If the soil is very dry before planting, fill each hole with water, allow it to drain for a minute or two, and . plant in the wet soil. Firming has to be judged so as to leave the plant firm but not packed down, and the surface soil should be loose.

Windy weather during or just after planting is far harder on the plants than drought, and if the plants are tall, it may be necessary to support them, using short stakes or twiggy shrub growth, so that the roots will not work loose in the soil.

Maintenance

Light surface hoeing keeps down weeds and keeps the surface of the soil loose, which acts as a mulch to conserve moisture. However, hoeing should be shallow, as constant chipping away of the tips of surface feeding roots is not conducive to good growth. Hoe damage or even bruising to roots or stems may be sufficient to allow the entry of disease.

Light mulches of lawn clippings or well-decayed compost may be beneficial from late spring through summer in keeping roots cool and conserving moisture. Mulching material should be distributed evenly over the entire root area to a depth of about. lin. to 2in„ but should not be heaped up round the stems of plants.

Manuring is not always necessary, especially on fertile soils or where the bed was thoroughly prepared before planting. Too rich feeding causes excessive leaf growth, making a large leafy bush with few flowers. Liquid manuring once the flower buds are developing increases flower production and flower size. Liquid manure should only be applied to damp ground and all fertiliser should be kept off the plant foliage because of the likelihood of burning; except, of course, in the case of foliar fertilisers.

. Watering should be done when the soil dries out. A thorough watering every week, the water being allowed to soak down to the root area, is preferable to several sprinklings where only the surface is moistened. If only the surface is wet, feeding roots tend to come up to the damp soil and if, for any reason, watering cannot be continued, the plants suffer seriously.

Cutting Flowers for Indoors

Flowers should be cut with scissors or secateurs, because all cuts are clean and should heal readily, and as many plant stems are tough, tugging at them to pick the flowers loosens the whole plant and may even pull it out.

Cutting the flowers is important in the maintenance of annuals, as the more blooms are cut the greater is the over-all flower production. Once flowers fade and seeds set, flower production slows up and ceases. For a

long display it is necessary to pick and keep picking. Even if flowers are not useful for decorative work, at least all spent flower heads should .be removed and not allowed to set seed.

Saving Seed

Sometimes a particularly good strain of plant may be found and it is desired to save seeds.

Seed should be kept only from healthy true to type or superior plants to maintain the standards already achieved. Off-type plants having small flowers, poor growth habit, or a small flower production should be discarded. Plants of poor type will probably set a prolific crop of seeds, but plants grown from poor seed can never be improved however much attention and energy are put into caring for them. There is always the possibility of cross-pollination, which would result in wide variations in the resulting plants.

Seed to be saved should be left on the plant until it is nearly ripe. If it is cut too early, the seed is immature and may not grow. If the collecting is left too late, the pod may shatter as soon as it is touched, and the seed be lost.

Seed pods or stems should be hung over or laid on newspaper to dry, and once the seeds have dried they can be put away for storage.

Seed is alive, though dormant, and should be kept in a cool place. The container should be proof against mice and insects. Tobacco tins and various kitchen tins would be suitable.

All containers should be clearly labelled with the plant name and year. It may be thought possible to remember each year by painting the tins in different colours, but it is better to

be sure and sow fresh seed. Old seed may germinate, but is not dependable, whereas a good strike usually will be gained with the fresh seed of most species. D’caaea Disease Rotation of crops should be practised because of the build up and carry over of disease. This is especially . important with asters, stocks, poppies, and petunias, which seldom give a good display the second year in the same bed ~ £ cultural details should be a guiding factor in planning and preparing for ing them ng n better able to withstand trouble Though rank, lush growth, caused by overfeeding and sheltered usually tions, may look healthy, it is usually less able to withstand attack than hardier grown material. Annuals, on the whole, are remarkably free from disease. Though they are troubled with virus, aphides, and thrips and suffer depredations from slugs, snails, and caterpillars, with reasonable care it is possible to garden for many years without having a serious setback.

Work for December

The Christmas rush is gaining momentum at this stage and the garden should be in such a state that work in it is reduced to a minimum.

Staking of dahlia, chrysanthemum, gladiolus, and any tall perennials should be brought up to date. Mulching materials around shrubs will probably need replenishing. Large additions of organic matter to a mulch should be made only when the soil is damp, but light replacements may be added at any time.

One good watering a week is better than splashes which just keep the dust down. Deep watering reaches the roots in the lower layers of soil, whereas light sprinklings moistening the top only encourage roots to rise in search of the water, and being nearer the surface, they suffer more if for any reason watering cannot be continued.

Annuals

Seed of aster, Phlox drummondi, zinnia, marigold, and petunia may still be sown for late summer display.

If planting of annuals has been neglected and plants are to be put in now, they must be planted in wellwatered holes. Careful attention to planting, followed by regular watering, will be necessary to ensure good growth. Plants which will survive transplanting now are gilia, cleome, bonfire salvia, and petunia, and seed of portulaca and Livingstone daisy may be broadcast in dry borders. Seed of biennials, sweet william, wallflower, and Cynoglossum amabile, and many perennials may be sown now to grow on to give flowers next summer.

Removal of Spent Flowers

To keep the garden bright, spent flower heads should be removed regularly from annuals, cutting them in

preference to pulling the old heads, as often the whole plant comes up with that treatment. Removing old dahlia flowers keeps the uses producing as well as making them look more attractive. Cutting away the top faded portion of Watsonia stems and delphiniums often induces small side buds to develop and form quite a good flowering stem, Roses . . „ As the mam flowering season passes rose bushes should be looked over and all spent flowers removed. In removincr spent flowers it is essential to cut b ack to a healthv bud This reduces the likelihood of die-back entering the stem and the bud breaks awa y lbto “’Si Bb™w 8 b ™ w A hy cutting 3 die Mind h d ° back to a healthy bud S tip back t 0 a bealthy bud - Climbing roses from now on develop long wands of succulent new growth. These growths will •be required for next year s flowers and as they are brittle and liable to Wind damage, they should be tied m. Rambling roses should be pruned immediately after flowering by the cutting out of old flowering stems from the base of the plant.

Wisterias

Wisterias also develop long rank growth during summer. On young plants these runners can be tied in place, when they will harden up in a year or two and form the basic framework to carry flowers and foliage. On old, large plants with dense growth long growths can be cut back to within six or so buds of the older wood. This will keep the wisteria more bushy and compact and often all the six buds will turn into flowering spurs. Irises Bearded iris can be lifted and divided and new plants put in now. Irises need a warm sunny situation to do well and can be given a dressing of lime at 4oz. per square yard every spring. When iris is planted the rhizome should not be covered with soil, but at least half of it should be left exposed on the surface.

Bulbs

Clumps of narcissi and daffodils which have increased and become too thickly matted may be lifted this month as soon as the foliage has withered and dried. For general garden display it is usually sufficient to lift narcissi once in 3 years and where the bulbs are naturalised in lawn or grass they may be left undisturbed for many years. Valuable narcissus bulbs left in the ground should be dusted every fortnight with 2 per cent. D.D.T. dust to protect them from bulb fly attack.

As lifting is carried out bulbs should be gathered. Leaving them exposed for several days increases the risk of the bulb fly laying its eggs among them and too long exposure to bright sunlight could cause scorching. Soft, rotten bulbs should be destroyed and plump healthy ones stored in a cool, dry, well-ventilated place until required for planting in February and March.