THE HERBACEOUS GARDEN

There is an old-fashioned ring about the terms ‘herbaceous and cottage gardens’ and here we look into these further.

The herbaceous border was much maligned over recent years, admittedly with an element of justification, when time and labour costs needed reducing in public parks and large gardens.

However, we should not criticise something of beauty when there are still keen gardeners prepared to undertake the work involved.  An herbaceous border can require plenty of preparation and constant maintenance, but then so do most other borders. 

What are herbaceous plants?

Before we start we ought to establish what exactly herbaceous perennials are.  Can I suggest we use the following general definition: “an herbaceous perennial is one that flowers perennially (every year) and has soft stems”.  I say this because a perennial plant is one that lasts for an indefinite period but this can also apply to trees and shrubs, the difference being that they do not die down to the ground each year.  So we can say that an herbaceous perennial has an annual stem and a perennial rootstock.  However, as always by way of contradiction many plants that are valuable in the herbaceous border, like red hot poker (Kniphofia), do not die down altogether! 

Planning an herbaceous border

The herbaceous border if cleverly planned can be one of the most spectacular and colourful features in any garden it is probably the most artificial form of natural gardening that has ever been devised. Designing and planning the border is fairly straightforward provided one or two principles are observed: first, it would be tempting to have in a border, say 7.5m (25 ft) long by 1 8m (6 ft) deep, with just three rows of plants — tall at the back, medium in the centre and short at the front.  Unfortunately this would give too uniform an effect that lacks interest and so we bring forward some back- row plants to the middle and some middle-row plants to the front to provide a variation.  Planting groups of three, five, seven or nine plants enables our design to have an irregular rather than a rounded shape and we can also arrange the plants to run into each other rather than leave gaps in the groupings.

In our planning we could organize an early border or an autumn border.  However, unless you are especially fond of one particular group of plants, it would be inadvisable to have a border devoted to, say, asters or delphiniums as the flowering period would be limited.  Although if you have a shady corner where little else will grow an exception could be paeonies; they will do very well here. 

Preparing your border

This is not complicated and involves straightforward digging, although this isn’t everyone’s favourite gardening task. 

Personally, my secret for digging a large area (or any task in life) is to break it up into smaller sections.  As I complete one section at a time I am pleased to have achieved a minor success and remain motivated to tackle the next area and so I continue enthusiastically and soon the larger area does not seem so daunting and is completed.  It also allows me time to think and consider work on other tasks that I can do that day.  

If the soil is sandy then you only need to dig out a single ‘spit’ (this is the depth of the spade being used).  You should then incorporate your composted garden material or well rotted manure (organic matter) in the bottom of this small trench; if the soil is heavy, you may need to double dig it (this is two spits deep and helps provide extra drainage).  Again, incorporate organic matter into the bottom spit.

Before planting, I apply a general fertilizer to the area and rake it in the plants will benefit as they try to establish themselves.  I strongly recommend spring planting for herbaceous plants.  There is a critical period during late March and April when it is best to plant and this can sometimes be extended into May if the spring season has been wet.

Choosing plants

If you like the idea of an herbaceous border, but you are still not sure of the types of plants you want, then may I suggest it would pay dividends to spend this season visiting garden centres and gardens open to the public.  In this way, you will get to understand how plants are used and placed, in relation to their colour, height and leaf texture as well as availability. You can then look through a catalogue or visit a garden centre and place an order in the autumn to ensure spring delivery.

Whenever I choose plants for my garden I take into account factors such as aspect, damp or dry soil and the length of period during which I want my display.  The longer the border, the greater options you will have for an extended display of colour.  You might consider when you take your holidays, as there is little point going to all this effort if the border is looking its best when you are not there. 

It is now over half a century since the mixed border came on the scene this combination of shrubs and herbaceous plants was very fashionable and has remained so with the greater range of plants for small gardens.  However, to maximise the effect you need an extremely wide border.  You can still see good examples of this at places such as the Royal Horticultural Society’s garden at Wisley, Surrey.  The ‘grand’ idea of the mixed border has been adapted to the context of today’s average-sized garden and the best compromise is to have an herbaceous border in front of shrubs that should ideally be early-flowering and if possible evergreen.

Staking and tying

One drawback to having herbaceous plants is that they need support, and staking which was why they went out of favour. This not only takes a long time but gives an ugly appearance to the border in the earlier stages.  The least attractive form of staking is with canes and string; pea sticks are best and should be used in May, when growth is just beginning to rise.  For a week or two, the border will look as if it is merely a collection of pea sticks.  Traditionally the pea sticks should be inserted close to each clump with the tops bent inwards above the clump, just below the height at which the plants will flower; the plants will continue to grow through the bent-over twigs and eventually conceal them entirely.  This style of staking will withstand the onslaught of the worst weather that even a normal British summer can produce.

An alternative is to use the various forms of metal support based on the same principle as the bent-over pea stick, with the plants growing through a ringed wire meshing.  The rings vary in diameter but may not be large enough for bigger clumps. The range of artificial supports now available in garden centres is vast and choice will depend on your own personal preference.

Island beds

Another development of the herbaceous border is to grow perennial plants in island beds.  This method will reduce the amount of staking required allowing the plants to mutually support one another.  In general provided you make a suitable choice of plants this idea works well but it obviously succeeds best in a large garden where there is room for a bed to be cut out of a lawn.

If we are not fortunate enough to have a large garden we can still design island beds into our garden.  Using groups of plants chosen because they do not grow very high island beds are useful in a small garden with narrow borders.  A more obvious benefit of an island bed is being able to walk around it and take a 360degree view of all our plants.