Herbaceous Plants for Borders
‘Herbaceous’ plants are soft-stemmed and not woody like shrubs. Although the term by itself includes bothand , gardeners nearly always use it instead with two other adjectives — ‘hardy’ and ‘perennial’. These in effect limit herbaceous plants to those that live for some years and are sufficiently resistant to cold to be grown outdoors in most parts of the country. They include such favourites as peonies, lupins, , phloxes and Michaelmas daisies and they play an important role in the stocking of most gardens.
They are more permanent than annuals and biennials, and less so than shrubs, but they reach maturity quickly and so can give gardens a well-furnished appearance long before trees and shrubs are of comparable size. Many of them associate well with shrubs and vigorous bush roses, and one currently popular planting scheme is to make a permanent framework of shrubs and roses filled in with a semi-permanent planting of hardy herbaceous perennials, with bulbs, annuals and biennials added as fillers and to keep the display going for longer.
A few hardy herbaceous perennials, such as hellebores and peonies, are best left undisturbed for a good many years. A few others, such as lupins and delphiniums, age rather quickly and are best renewed quite frequently. Most benefit from lifting and replanting every three or four years and this can provide a welcome opportunity to re-model the planting, correct mistakes, and introduce new varieties and generally indulge in second thoughts.
Not many hardy herbaceous perennials, and certainly none of the popular kinds, are fussy about, most thriving in anything that is reasonably fertile and well drained. A few like abundant moisture, and though most prefer light places, enough either prefer or tolerate shade to make it easy to find candidates for every growing position.
Most herbaceous perennials are easy to manage. Some of the taller kinds, or those with slender stems, may require support and there are numerous ways to do this. One is to push twiggy branches into the soil in spring so that stems grow up through them; another is to use metal hoops or half-circles in much the same way. Canes or stakes with encircling ties of soft string are another possibility, and you can also buy miniature hurdles which look picturesque and can be used to prevent plants flopping over paths and.
KEEPING THEM HEALTHY
Herbaceous plants suffer very little fromand only occasionally require spraying with insecticides or fungicides. They may require watering in dry weather and will grow more vigorously if fed in spring — and possibly again in early summer — with a well-balanced compound fertilizer containing nitrogen, phosphate and potash in more or less equal proportions. They should be kept clear of and in autumn the stems of deciduous kinds should be cut off a little above ground-level. Faded flowers or seed heads can be removed much earlier, but this depends on whether or not you regard them as unsightly, or need to take them for home-produced seed.
Weeds should be removed regularly by hand-or hoeing, and in autumn the soil can be lightly forked to remove any remaining weeds and loosen the surface. It is unwise to disturb the soil to a greater depth than 5-6cm (2 – 2-1/2in) as there may be many feeding roots quite close to the surface.
WHERE THEY FLOURISH
Herbaceous plants are usually grown in borders, most of which are usually rectangular or curving, or in island beds which are almost always irregular in shape and size and are usually separated by grass paths or wider expanses of lawn. Both borders and beds need to be fairly large for an effective display (180cm/6ft minimum width for borders), especially if roses and shrubs are to be mixed with the herbaceous plants — a useful device for prolonging the flowering season. If you add some evergreen shrubs and varieties with coloured stems, these will provide a permanent framework which will remain interesting in winter when nearly all the herbaceous plants have died down to ground level.
Shrubs and shrub roses may be planted singly but herbaceous plants, except for a few very large kinds, are usually best planted in groups, forming irregular colonies of various shapes and sizes. Obviously, most of the short plants should be at the front and the tall ones at the back, but there should be some flexibility so that the final effect is of sweeping bays of foliage and flowers not a regularly graded slope.
If you are aiming for a long flowering season, you can avoid being stuck intermittently with uninteresting patches by making each group rather long and narrow, with something else in front or behind that will flower at a different time and conceal the plants that have finished or are yet to flower. The use of plenty of goodcan also make amends for seasonal shortages of bloom. Spring-flowering bulbs will add early colour, dying down by the time most of the herbaceous perennials are coming into full growth. In summer other temporary plants with an extended flowering season can be used to maintain continuous interest and colour.