This term is used to describe a plant which does not die after flowering, but persists for a number of years, in contrast with an annual which flowers once and then dies after setting seed, and a biennial which completes its life-cycle in two years. The term ‘perennial’ may properly be applied to shrubs and trees but is more often used in conjunction with the term `hardy herbaceous’ to describe the plants which form the mainstay of herbaceous borders, though they are often grown in other parts of the garden, either in company with other plants or as isolated specimens. Though the term is applied to plants which live for more than 2 years, many perennials live for many years and such plants as herbaceous paeonias and the oriental poppy (Papaver orientale) are particularly long lived. By contrast some perennial plants, for instance lupins, may have a life-span of only five or six years.
Planting perennials With herbaceous plants, one of the problems is not so much how to plant them as when. The vast majority of border plants are pretty tough and perennials such as Michaelmas or Shasta daisies will quickly take root and establish themselves even if they are left lying on the soil surface.
Most border plants, too, can be planted, weather and soil conditions permitting, at any time from September to March.
But there is an important minority which planted in autumn, seem unable to survive their first winter. Catmint (Nepeta x faasenii) is one of the classic examples of this characteristic, a characteristic that is shared by other grey and silver-leaved perennials. Reputable nurserymen will automatically defer delivery of this kind of plant until early spring.
The actual operation of planting perennials is simple and straight forward.
Planting with the new season’s dormant shoots a few inches below soil level will be satisfactory for most of the better‑ known and more widely-grown border plants. Where established clumps are being divided up, it is the younger and more vigorous outside shoots that should be planted.
Herbaceous paeonies require very shallow planting; putting them in too deep is one of the main causes of delay in flowering and poor crops of bloom. The dormant eyes, which are easy to distinguish, since they are crimson in color, should not be more than an inch below soil level.
Bearded irises are another group of border plants that require the shallowest of planting. Ideally the rhizomes should actually be resting on the soil with their upper surfaces above ground level, though on light soils, particularly, they may be planted so that the rhizomes are just covered with soil. This covering will gradually be washed away by rain, by which time their roots will have taken hold. They are rather tricky to plant and are easily disturbed by subsequent weeding or cultivating until the fleshy anchoring roots have had a chance to take hold. It is better to keep the hoe or fork well away from them during their first season and carry out any necessary weeding operations by hand.
The herbaceous border, which is a comparative newcomer to the garden scene, is still one of its most popular features. Introduced at the turn of the century by Gertrude Jekyll as a protest against the monotonous formality of Victorian garden design, its popularity has steadily increased until today there are few gardens without some kind of perennial border to enhance their beauty throughout the months of summer and autumn.
Restricted originally to plants of purely perennial habit—in the main, those whose growth begins afresh from ground level each year—the terms of reference have gradually been extended so that today we find included not only spring and summer bulbs and corms but also small shrubby plants and those curious in-betweens whose woody top growth persists throughout the winter, but which otherwise display most of the characteristics of true perennials. These are the sub-shrubs, of which plants such as the plumbago-flowered Ceratostigma willmottianum, Caryopteris clandonensis, and the Russian sage, Perouskia atriplicifolia are typical examples.
Preparing the site Preliminary preparation of the site for a herbaceous border is of paramount importance. Much of its subsequent success or failure will depend on the thoroughness with which it is carried out. Some soils, of course, are a good deal more difficult to prepare than others, but whether you garden on heavy, back-breaking clay or easily managed, well-drained sandy loam there must be sufficient supplies of humus in the soil if the plants are to give of their best.
Deep digging and thorough cultivation are two further essentials. Most of the occupants of the border will remain in the same positions for at least three years, while other more permanent specimens such as paeonies, hellebores, romneyas and hemerocallis can stay put almost indefinitely, without the necessity for division or replanting.
To make sure that such conditions are fulfilled it may be necessary to double dig the whole of the projected plot. This will result in a thorough breaking up of both the surface and second spits of soil. As far as medium to light well-drained loams are concerned, bastard trenching, which leaves the lower spit in situ but broken up with a fork, is probably just as effective, but it is better to give wet, heavy soils the full treatment.
Humus Thorough digging, however, is not sufficient to create the soil conditions in which perennials thrive best. To provide them, plentiful supplies of humus or humus-forming material must be present in the soil, enough, in fact, to satisfy much of the plants’ needs for several seasons, as normally the border will be due for a complete overhaul only once in every three to four years.
Humus can be provided by a variety of materials, the best of which, of course, is the almost impossible to obtain stable or farmyard manure. Most of us, however, will have to settle for alternatives. Compost, properly made and well rotted down, heads the list of these but supplies of this are quickly exhausted unless we supplement our garden and domestic waste with straw, sawdust, or other similar materials brought in from outside.
Leafmould is excellent, but expensive unless you are lucky enough to have access to natural sources of supply. Oak and beech leaves are the richest in plant foods, while bracken rots down to a material of peat-like consistency, good for stepping up the humus content of the soil but otherwise lacking in plant foods. Young bracken shoots, on the other hand, are rich in plant foods and minerals and make a valuable contribution to the compost heap.
For the town gardener and for those who cannot readily obtain the materials mentioned above, peat is the best soil conditioner. It is clean both to store and handle, and can hold many times its own bulk of moisture.
Spent hops are another first-rate humus-forming material. If you can obtain supplies in bulk from a local brewery, they will be relatively cheap. The so-called hop manures with added organic fertilizers are a convenient but expensive method of supplying humus to the border.
These, or any other similar materials, are best worked into the upper spit as digging progresses. Alternatively they can be forked into the soil a few weeks before the plants are put in.
Fortunately, the vast majority of the more widely-grown herbaceous perennials are very accommodating. They will thrive in most types of soil although characteristics such as height, vigor and rate of increase will vary considerably between, for example, light, sandy loams and heavy, sticky clays. It is a good rule never to coddle temperamental plants. There is neither time nor room for them in the herbaceous border, where plants are grown more for their effect in the mass than as individuals.
Weeds The best time of the year to prepare the site for planting is late summer or early autumn. This will give the winter frosts a chance to break up heavy clods to a fine planting tilth. This, of course, is not so important with light sandy soils which can be cultivated at almost any season of the year. As digging progresses, it is imperative to remove every possible vestige of perennial weeds; the aim should be to start with a site that is completely weed-free, although when fresh ground is being taken over this can be no more than a counsel of perfection.
Watch particularly for the roots of bindweed, ground elder and couch grass. Any of these can soon stage a rapid comeback even if only a few pieces remain in the soil.
Couch grass, or ‘twitch’ as it is sometimes called, is easily recognizable; the narrow leaf blades are coarse, with serrated edges; leaves and underground runners are sectional, like miniature bamboo shoots, with nodules at the joints. Ground elder has leaves similar to those of its shrub namesake and quite attractive flowers. It is easily identified by the pungent aroma of its bruised leaves and stems. Bindweed, also known as bellbind in some parts of the country, has attractive white trumpet-shaped flowers and a twining habit that can strangle any plant that is the object of its attentions.
Any of these weeds are anathema in the border and once established will prove well-nigh impossible to eradicate without a complete overhaul. Other perennial weeds—not quite as difficult but still a nuisance—include docks, thistles, clover and creeping buttercup. In acid soils sorrel, too, can be troublesome.
If annual weeds multiply alarmingly, and they will in very wet summers, there is no need for undue despondency. Regular sessions with a hand fork or a lady’s border fork will keep them in check. Vigorous low-growing perennials will act as their own ground cover.
In autumn, and in early spring if possible, the border should have a thorough forking over, removing and burning all perennial weeds. Any clumps of plants that show signs of weed infestation should be dug up. After shaking or washing their roots free of soil, offending weed roots or runners that have penetrated the latter should be carefully teased out and removed. The clumps can then be replanted in situ, or if their siie warrants it, be split up and re-grouped. If the replanting is carried out without delay the plants will not suffer any check. In fact, very vigorous growers such as Michaelmas daisies, Campanula lactiflora and Chrysanthemum maximum will benefit from this procedure.
It follows from the foregoing that new stocks received from the nursery or from generous fellow-gardeners should have their roots carefully examined for invading weeds before they are put in. We may not be able to suppress entirely the weeds that are present in the soil, but there is no point in deliberately planting trouble.
Supplementary dressings Unless farmyard manure has been available in generous quantities it will be advisable to give a booster of some kind of fertilizer a few weeks before the border is planted.
Bonemeal and fish manure, which are both organic and slow-acting, will give good results, applied at a rate of 2-3 oz to, the square yard. As an alternative, a good general fertilizer can be used at the rate recommended by the manufacturers.
A good way of distributing this supplementary plant food is to rake it into the soil when the final preparations for planting are being made. Alternatively, it can be pricked lightly into the surface with a fork. An established border will benefit from a similar dressing when growth starts in spring.
Siting Most of the more widely-grown perennials are sun-lovers, so that a position facing south or west will be the most suitable for the border. But since this feature is seen at its best when viewed lengthwise, it may be necessary if we plan to enjoy its beauty from some fixed vantage point such as a terrace or the living room windows, to effect some sort of compromise where aspect is concerned.
Generally speaking, any position except a sunless north-facing one. or one where the plants suffer shade and drip from overhanging trees, will be quite satisfactory.
Background Just as a fine picture deserves an appropriate frame, so the herbaceous border needs a proper setting for its beauty. In the past this has usually been supplied by a background wall or hedge, but nowadays double-sided and island borders are becoming popular, where the only background is provided by the adjacent grass or paving. Nothing, however, makes a more suitable backcloth than a well-kept evergreen hedge—yew, holly, cypress, beech, or hornbeam. Mellowed brick or stone wall, too, can act as a pleasing accompaniment, and even wattle hurdles or a wooden fence, when discreetly covered by climbing plants, can provide an attractive setting.
Plants grown against walls or fences will require additional attention where staking and tying are concerned. In rough weather strong gusts and eddies develop at their base which can have disastrous results unless the plants are strongly secured.
Hedges, beautiful though they may be as backgrounds, also have their disadvantages. Most hedging plants are notorious soil robbers. Some, such as privet, are much worse than others and should be avoided if a new planting is to be made. The roots of an established hedge can be kept in check by taking out a trench a foot or so away from the base of the plants and chopping back all the fibrous roots with a sharp spade. This operation, which should be carried out while the hedge is dormant, could very well coincide with the periodic overhaul and replanting of the border.
If space permits, it is a good plan to leave a gap of 2-3 feet between the foot of the hedge and the rear rank border plants This, incidentally, will also provide useful access to the back of the border for maintenance work.
Yew, of course, is the best plant for a background hedge. Slow and compact in growth, it requires a minimum of attention—one `short back and sides trim annually will suffice, and its foliage of sombre green is the perfect foil for the bright colors of the border plants.
Planning Planning the border can be fun. With squared paper and a sheaf of nursery catalogues there could be few pleasanter ways of spending a winter’s evening by the fire. Ready-made collections complete with planting plans are useful for the complete novice and can form the nucleus of a wider collection, but it is a good deal more interesting to work out your own color schemes and to see the plans coming to fruition in the garden.
There is such a wide choice of herbaceous plants that the permutations and combinations of color, form and texture are infinite in number. Individual tastes vary and so do fashions in flower colors. The pastel shades, popular for so many years, are giving place to the stronger reds, yellows and blues of the Victorian era.
A border composed entirely of any one of these primary colors would be striking in its effect, but the planning would need very careful handling and a thorough knowledge of plant characteristics. If you lack experience, you would be well advised to use a mixture of colors, grouped according to your individual taste.
As a general rule, in a border of mixed colors the paler shades should be at each end, with the brighter, more vivid ones grouped mainly at the centre. For example, the pure whites of Phlox paniculata alba, Achillea ptarmica The Pearl’, and Gypsophila ‘Bristol Fairy’ could melt almost imperceptibly into the cool primrose yellows of Achillea taygetea and Verbascum bombyciferum (syn. broussa), flanked by the deeper yellows of Hemerocallis ‘Hyperion’, one of the best of the free-flowering day lilies, and Lysimachia punctata, the yellow loose-strife.
The middle of the border could explode into brilliant color with scarlet Lychnis chalcedonica, Lobelia fulgens, Potentilla ‘Gibson’s Scarlet’, and the garnet-red Astilbe ‘Fanal’. Once past its climax, the border could progress to white once more through the blues of delphiniums, sea holly (Eryngium maritimum) whose leaves, as well as the flowers, are metallic blue, and the stately Echinops ritro, with thistle-like dark green foliage and drumstick flower heads of steely blue. Other suitable blue perennials include the attractive indigo-blue monkshood, Aconitum ‘Bressingham Spire’ and the curious balloon flower, Platycodon grandiflorum.
These could be followed by the soft pinks of Geranium endressii, Sidalcea `Sussex Beauty’, the long flowering Veronica spicata —Pavane’ and ‘Minuet’ are both good varieties—and the later-blooming ice plant, Sedum spectabile ‘Brilliant’.
And so back to white again, this time represented by Japanese anemones, Anemone hupehensis ‘Honorine Jobert’, Lysimachia clethroides, Potentilla alba and a good garden form of the sweetly scented meadow sweet, Filipendula ulmaria plena.
This, of course, would not constitute a complete planting plan, but is merely suggestion that could form the framework of an attractive herbaceous border. color, though it may take pride of place in the overall display, is not everything where the successful herbaceous border is concerned. The form and leaf texture of the plants, as well as the manner in which they are grouped, all play a part that is vitally important to the ultimate effect.
It is important to plant in relatively large groups, each restricted to one kind or variety, the size depending on the overall dimensions of the border. Blocks of three plants should, as a general rule, be the minimum, while, for smaller edging and carpeting plants, six would be a reasonable number if spottiness is to be avoided.
Although the general trend should be towards ‘shortest in the front, tallest in the rear’, this is a rule that should not be too rigidly adhered to. Some of the taller plants should be allowed to wander to the middle or even, at certain points, to the front of the border while the lower marginal plants can be permitted to flow unobtrusively inwards to make small pools and rivulets of contrasting height and color among their taller neighbours.
A number of perennials are grown as much for the beauty of their foliage as for the decorative quality of their flowers. Outstanding among these are the hostas, or plantain lilies with their outsize ribbed leaves; acanthus, whose sculptured foliage formed the classic model for the ‘Corinthian capitals of Ancient Greek architecture, hemerocallis, Iris sibirica and kniphofias for the contrasting effect of their sword-like leaves, the variety of rue known as Ruta graveolens ‘Jackman’s Blue and others.
Other plants are cultivated for their attractive seed heads. These include the fascinating but invasive Chinese lanterns (Physalis), the silvery tasselled Pulsatilla vulgaris or Pasque flower, Baptisia australis with its soot-like seed pods and the magnificent Heracleum mantegazzianum, a garden plant resembling a giant cow parsley whose outsize flat seed heads are borne on stems, 10 feet or more tall.
Planting The great majority of perennial border plants can be planted with safety between the end of September and the last week of March. In fact, the planting of late-flowering specimens such as Michaelmas daisies and border chrysanthemums could very well be delayed until April.
Planting holes should be of sufficient depth and breadth to accommodate the roots of the plants without bunching or overcrowding. Small plants can be firmed in by hand, but for large clumps the heel of the boot will be required. Although firm planting is desirable, this should not entail embedding the roots in a pocket of sticky ‘goo. In heavy clay soils, planting will have to be delayed until the soil condition improves or, better still, the holes can be filled with sifted compost or a mixture of dry soil and peat that has been kept under cover for this purpose.
With the more vigorous perennials such as golden rod, Shasta daisies, achilleas and campanulas, it is not necessary, if time presses, to be too fussy over planting procedure, provided that the soil has been properly prepared and is in good heart. Others, however, such as paeonies, alstroemerias and hellebores will need more careful attention. Paeonies, for example, should never be planted with their dormant growth buds more than approximately 2 inches below the surface; planting too deeply is one of the commonest causes of failure to bloom satisfactorily. The planting or division of catmint is better delayed until spring. Autumn-planted specimens frequently fail to survive.
This is a rule that might well be applied to all grey-leaved border plants. Once established they can tolerate severe weather conditions but in their first winter they often succumb to severe frosts if they are planted in autumn.
For the newcomer to gardening, the importance of dealing only with reputable nurseries cannot be overstressed.
Their catalogues, in addition to lists and descriptions of plants, will often contain a wealth of information regarding their likes and dislikes. Plants, too, will be delivered at the most appropriate time of year for planting out.
Choice of plants Anyone starting an herbaceous border from scratch would be well advised to take advantage of the many new plants and modern varieties of older favourites that require little or no staking and tying. By this means, one of the major summer chores in the border can be considerable reduced.
Many of these new-style border plants are entirely self-supporting; others need only a few twiggy sticks pushed in among them to keep them in order.
Plants such as tall delphiniums will, of course, have to have each individual flower secured to a stake or stout cane. If space permits, it is better to segregate these and other similar top-heavy plants; they do better where they are more easy to get at for maintenance.
Not all the taller border plants suffer from this shortcoming; Artemisia lactiflora, for example, is a plant whose 6 foot stems of feathery milk-white flowers,. smelling like meadowsweet, will stand up to a howling gale without turning a hair, while others, for example the moon daisies and taller perennial asters, will collapse and sprawl at the first hint of rough weather, if they are not securely staked.
Careful and judicious selection at the planning stage, therefore, can make the border practically trouble-free where staking and tying are concerned.
Double-sided or ‘island borders achieve similar results in a different way. Plants grown in an open situation are sturdier and more compact than those grown against a wall or hedge which tends to cause them to be drawn both upwards and outwards. This sturdier habit makes them less liable to damage by heavy winds and rough weather, and,in addition, access at both sides of the border makes routine maintenance a good deal easier. The idea of a double sided border is not new. Formerly, in large gardens, they were commonly used as a decorative edging in the kitchen garden where they served the dual purpose of screening the vegetable crops and providing flowers for cutting.
Island borders, however, are a more recent innovation, for whose introduction we have largely to thank an Englishman, Mr Alan Bloom, whose display borders attract a host of admirers each year.
One of their attractions, in addition to ease of maintenance, lies in the fact that they can be viewed from above as well as along their length and from the front.
For this reason, the height of the plants should not exceed 3 or 4 feet in order that the kaleidoscope color effects of the plant groupings can be seen to their best advantage.
Prolonging the display One of the main disadvantages of the herbaceous border as a garden feature is the comparatively short period during which it makes a major contribution to the garden display.
Normally, it is only in early or mid-June that it really starts to make its color impact, with lupins, oriental poppies, irises, anchusa, aquilegias and other June-flowering perennials.
Reaching its peak in July and August, it continues to delight in early autumn and retires in a blaze of Michaelmas daisies, red hot pokers, perennial sunflowers and border chrysanthemums, which carry it through, in most districts, until mid-October.
For the other seven months of the year, however, the border can lack color and interest, unless steps are taken to extend its scope by supplementing the orthodox planting materials with others that flower both early and late.
Spring bulbs, such as daffodils, tulips, hyacinths, chionodoxas, scillas and grape hyacinths, all make first-class curtain raisers and will fill the spaces between perennials with bright spring color. A little later, wallflowers, polyanthus, forget-me-nots and other spring bedding plants can be used as gap-fillers.
There are quite a few true herbaceous plants, beginning in January with the hellebores, that will considerably extend the border’s period of interest and relieve the monotony of bare brown earth and dead stems. Helleborus niger, the Christmas rose, seldom fulfils the promise of its name unless it has the protection of cloches or a cold greenhouse, but it can be relied on to open its pure white chalices by the middle or end of January, although even then it will still appreciate a little protection to save its immaculate petals from damage by wind and rain.
Following close on its heels comes the Lenten rose, Helleborus orientalis and other delightful species that include the stately H. argutifolius (syn. H. corsicus) and the native H. foetidus, whose green flower clusters are a good deal smaller than those of the Corsican species.
In February and March, too, there will be the pink and carmine flower trusses of the bergenias, among the finest of flowering perennials. These useful plants, that used to be called megaseas, are outsize members of the saxifrage family and most species are evergreen so that their handsome fleshy leaves, bronze or reddish in winter, as well as their striking flowers, make a valuable contribution to the winter border. ‘Ballawley Hybrid’, a relatively new introduction from Ireland, is one of the most outstanding examples of the group. Other good forms and species include B. cordifolia with rounded crinkly leaves, B. crassifolia, probably the most commonly-seen, whose leaves are more spoon-shaped than round and B. schmidtii, an unusual species the leaves of which have hairy margins and whose loose sprays of clear pink flowers are the earliest to appear.
Blue flowers are always attractive and there are several perennials to provide them once winter is over. The so-called giant forget-me-not, Brunnera macrophylla (syn. Anchusa myosotidiflora) is one of these, as are the lung-worts or pulmonarias. Both of these have foliage that stays attractive throughout the remainder of the season.
There are several species of pulmonaria, the most striking of which is P. angustifolia azurea, with clear gentian-blue flowers. It looks superb in conjunction with the yellow daisy flowers of the leopard’s bane, Doronicum ‘Harpur Crewe’. P. angustifolia rubra has coral-red blossoms, those of P. saccharata are pinkish-purple turning to blue; the multi-colored appearance is responsible for its nickname of soldiers and sailors, while its strikingly-mottled leaves have earned it the popular title of spotted dog. Incidentally, the foliage of all the lungworts, which remains tidy throughout the summer, acts as an excellent weed-cover.
In the shadier parts of the border Hepatica triloba with its leathery, ivy-like leaves and true-blue flowers, together with primulas and polyanthus will all make pools of color in April and May. The golden flower of Alyssum saxatile fore pleno will shine even more brightly in association with the white flowers of the perennial candytuft Iberis sempervirens ‘Snowflake’, in sunny spots at the edge of the border.
Heucheras and heucherellas will enliven the early summer scene with their spikes of brilliant coral and clear pink miniature bells. The latter is an interesting hybrid between heuchera and tiarella, the foam flower, which is useful both for its decorative value at this time and as an evergreen carpeting plant later in the season. All these will do well in partial shade.
A complete contrast both in flowers and its ferny foliage is Dicentra spectabilis, the lyre flower, better known to cottagers as bleeding heart, lady’s locket or Dutchman’s breeches. This plant prefers partial shade and blooms in late spring, at the same time as the graceful Solomon’s seal, Polygonatum multiflorum, with its hanging bells of greenish white.
To provide color continuity from late summer onwards there are, in addition to the indispensable Michaelmas daisies, various other perennial and bulbous plants. The grey-leaved Anaphalis triplinervis is one of these. Its papery ‘everlasting’ white star-like flowers, which first appear in July, will still be immaculate in October. The Japanese anemone, Anemone hupehensis, of which there are now many lovely named varieties, will start to put up clusters of chalice-like blossoms from early August until the first heavy frosts arrive. The single forms, both pink and white, are still firm favourites, but if you are looking for something out-of-the-ordinary you might like to try `Margarete., a double pink, with rows of ruff-like petals. ‘Prince Henry., sometimes listed as ‘Profusion’, is one of the most striking singles, its color much richer than those of the other pinks.
In sheltered bays in the border from August onwards two closely-allied South African bulbous plants will make a welcome splash of color. The blue African lily, agapanthus—the species A. campanulatus is perfectly hardy in the south of England — has drumstick heads of powder-blue flowers, while those of Nerine bowdenii are similar, but less tightly packed with pink florets. ‘Fenwick’s Variety’, an attractive pink, is the best form for out-of-doors.
And so the year goes by in the herbaceous border, with the first Christmas roses plumping up their buds as the last lingering flowers of the border chrysanthemums shrivel and fade. In the well-planned perennial border there need never be a dull moment.
Winter work Apart from the periodic division, replanting and occasional replanning of the border, winter maintenance will consist mainly of tidying-up and light forking between the plants. There are two schools of thought where the former operation is concerned. Some gardeners prefer to leave the tidying of the ,border until spring—the dead leaves and stems, they claim, protect the crowns of the plants in really severe weather. Others, who cannot stand the sight of so much dead untidy vegetation cut down the dead stems at the earliest opportunity.
There is a lot to be said for the former point of view, but a lot will depend on how the border is sited. If it is in full view of the house windows, the sooner it is made ship-shape the better. Only a very small number of popular herbaceous perennials are delicate enough to suffer irreparable damage, even in the severest winter. Plants such as eremurus and Lobelia fulgens, which may be damaged by frosts, can be protected by covering their crowns with weathered ashes or bracken.
Where the border is more remotely situated, clearing up operations can take their plaee in the queue of urgent garden tasks that make their heaviest demands during the winter months.
Other uses of herbaceous plants Perennials have become so closely associated in our minds with the herbaceous border that we tend to overlook their many other uses in the garden. For example, bedding schemes employing perennials can be just as attractive as those in which the more orthodox hardy and half-hardy annuals are used. What is more important, management and upkeep will be be simplified and costs will be less where these versatile plants are utilized.
Perennials as bedding plants For bedding purposes, it will be necessary to choose perennials with a relatively long flowering season and/or attractive foliage, plus a solid and compact habit of growth. Among those fulfilling such requirements are Brunnera macrophylla (syn. Anchusa myosotidiflora), the so-called giant forget-me-not, Anemone hupehensis, the Japanese anemone, Armeria maritima, thrift, the medium and dwarf Michaelmas daisies and dwarf del-phiniums, for example D. ruysii or D. chinensis. The two last-named, in common with a number of other perennials, have the added advantage of being easy to grow from seed.
Segregation of groups and species Another good way of making the best use of certain groups and species is to grow them in beds restricted to the one type of perennial. By growing them in this way, it is easy to make satisfactory provision for their special requirements in the way of feeding, staking, tying and general cultivation.
This works well for herbaceous plants such as lupins, flag irises, paeonies, oriental poppies and the taller delphiniums. A further point in favour of this method is that it avoids the bare patches that tend to appear in the border when such early-flowering perennials form part of the general scheme.
Other herbaceous perennials that will benefit from this method of culture are the Michaelmas daisies. Where sufficient space is available, a representative collection, grown in a bed or border devoted to them would make a far greater impact than they would dotted about in groups in the mixed border.
Waterside planting Although the great majority of perennials will thrive in a wide range of garden soils and situations, there are some that prefer shade and moisture, conditions that cannot always be easily provided in the herbaceous border. These make excellent plants for the waterside—by the banks of streams or artificial watercourses or at the edge of a garden pool.
Primulas, astilbes, Iris sibirica and Iris kaempferi, kingcups (Caltha palustris) and the globe flower (Trollius species) are just a few plants that will grow better in damp, shady positions.
Cut flowers Satisfying the demands for flowers for the house in summer, when they fade so quickly, sometimes results in the display in the border being spoiled by too lavish cutting. A satisfactory way of avoiding this is to grow perennials especially for the purpose, either in rows in the kitchen garden or bordering the vegetable plot. For this, it is only commonsense to choose those that will not only cut and last well, but will also need minimum attention where staking and tying are concerned. The list (right) is representative, but far from exhaustive.
It should be obvious, from the foregoing, that the uses of perennials are many and varied. We are doing ourselves a great disservice if we restrict them solely to the herbaceous border.
Monocarpic plants Although the literal meaning is ‘once-fruiting’, as far as gardeners are concerned, plants which take an indefinite period to reach their flowering age and die immediately afterwards are said to be monocarpic. They represent only a small number of plants, but examples familiar to many gardeners include some meconopsis species, Saxifrage longifolia, Saxifraga ‘Tumbling Waters’, house-leeks (sempervivums), most bromeliads, and the so-called century plant, Agave americana, which, although it does not take a hundred years to flower and then die, may well take over fifty years. Annuals and biennials differ from monocarpic plants in that their life cycles are limited to one year in annuals and two years in biennials.
A selection of herbaceous plants
|Achillea spp Et vars||1-4||white, yellow||June—Aug|
|Aster spp 8 vars||1-5||various||Aug—Oct|
|Erigeron hybs||1-2||blue, pink||June—Sept|
|Gaillardia hybs||2||yellow, orange||July—Aug|
|Heuchera hybs||1-2.5||pinks, reds||May—Aug|
|Paeonia spp Et hybs||2-4||pink, red, white||May—June|
|Veronica spp Et vars||1-3||blues, mauves||July—Oct|
|Perennials for cutting|
|Anaphalis triplinervis||0.5||white ‘everlasting’||July—Aug|
|Aquilegia hybrids||up to 3||various||May—June|
|Aster (perennial)||up to 5||white, pinks, purples||Aug—Oct|
|Heuchera spp Et varieties||2||pinks, reds||June—July|
|Iris germanica||up to 3||various||May—June|
|Phlox decussata||up to 3||various||July—Sep|