Herbaceous perennials - Border and rockery perennials
Traditionally herbaceous perennials are plants which can survive the winters, dying back at the end of autumn, then new growth appearing in the spring. There are several exceptions. Plants such as Pampas, Brunnera and Saxifrage are evergreen. It is a good idea at the planning stage to include some of these to provide colour for the winter months.
Some perennials, like Aquilega and Perennial Flax, cannot survive the winter months, especially in the north of England and Scotland, and therefore expect a limited life-span.
After 2-3 years growth it is advisable to lift and divide the plants, giving them room to grow again. The few true perennials, for example Paeonies and Acanthus, are best left undisturbed to flourish.
There are many plants classified as herbaceous perennials. Those growing to 30cm (1ft) and higher are classified as Border Perennials. The low, ground hugging ones are usually classified as Rockery Perennials.
After 2-3 years growth it is advisable to lift and divide the plants, giving them room to grow again. The few true perennials, for example Paeonies and Acanthus, are best left undisturbed to flourish.
There are many plants classified as herbaceous perennials. Those growing to 30cm (1ft) and higher are classified as Border Perennials. The low, ground hugging ones are usually classified as Rockery Perennials.
Border perennials
Preparation and planning
These plants are best left undisturbed for 2-3 years so initial preparation is very important. Ensure your soil has plenty of organic matter and nutrients, with good drainage. Perennials do not normally like acid soil, so check the pH before you begin. Remove all perennial weeds.Make a plan of your border, taking into account the climate and eventual size of the plants. Traditionally an herbaceous border has a backdrop such as a fence or brick wall, and the plants are arranged with the tallest plants at the back, leading to smaller plants at the front. The larger plants usually require staking for support, so a gap of 2-3ft between the fence and plants is a good idea. This enables you to adjust the stakes and keep the plants secure as they grow.
It is also advisable at this planning stage to think about the colour of the flowers. Do you want a bold splash of colour, or a blend of matching colours? Some people prefer to have various shades of the same colour, ranging from dark to pale.
To provide for winter colour, in the modern garden you can plant roses and shrubs in between and use bulbs and bedding plants to fill in the gaps until your plants reach maturity. The bulbs provide a nice display in the spring, when the new growth on other plants is just breaking through.
Planting
In colder northern climes it is better to leave planting until spring, but in the south it is possible in the autumn, even winter, if the weather is mild and he soil free draining. Early planting enables the root ball to grow and make the plant more secure at a time when there is no foliage.Plant in groups of 3-5. One specimen on its own would just look lost.
Using your plan, mark out the soil with small furrows or use pegs.
Make a hole large enough for the root ball of the plant and make sure you firm the soil around the base after planting, to keep the plant secure. If the weather turns bad after planting check the root ball is still secure. In the spring, keep the soil moist to encourage growth.
Support stakes, when required, should be added when the plants are about 30cm (1ft) high. These can be pea sticks, wire frames or canes.
In the modern, smaller gardens then it may be preferable to make an island border. This is more toward the centre of the garden and has the advantage that it can be viewed from all sides. Place the larger plants in the middle and the smaller to the edges.
If you have a garden which is susceptible to strong winds then it may be advisable to use smaller specimens which don't require staking.
Aftercare
Plants use up nutrients to develop seed heads so dead head regularly to encourage a new flush of flowers.As plants start to die off, cut back the yellowing stem gradually, don't cut into the green stem.
In autumn, cut most plants back to 5-8cm (2-3"). For the more tender plants, wrap the foliage around the crown for protection in winter.
Wait until the leaves from any nearby trees have fallen then lightly fork the soil.
After approximately 3 years some of the plants will have filled the space allotted to them and need lifting and dividing. Repeat this with various plants over the next 2 years and your border should always look healthy. Gradual thinning this way ensures continuity in your display.
In the spring add bone-meal or balanced organic fertilizer, about 65-100g/sqm (2-3oz/sqyd)
A layer of peat or mushroom compost acts as a mulch. Add this when soil is damp and it conserves the moisture and helps repress annual weeds.
Rockery perennials
There are a variety of plants suitable for rockeries, and the dwarf herbaceous perennials are ideal. Often known as alpines, because they are found growing wild in mountain ranges such as the Andes and the Himalayas, these plants flourish in the free draining soil of a rockery. Edelweiss, found in the Swiss Alps, is a prime example. It is a hardy, low growing plant which loves the sun.
Some true alpines can survive the British winters and are superb specimens for your rockery. Others cannot stand the wind and frost of the winters and need to be kept in an Alpine House or cool or cold greenhouse.
Check the growing conditions needed for your plant before planting, and use the hardier varieties, such as Alyssum and Saxifrage, which are known to thrive in the U.K., especially if you have a northern aspect or strong winds.
Some true alpines can survive the British winters and are superb specimens for your rockery. Others cannot stand the wind and frost of the winters and need to be kept in an Alpine House or cool or cold greenhouse.
Check the growing conditions needed for your plant before planting, and use the hardier varieties, such as Alyssum and Saxifrage, which are known to thrive in the U.K., especially if you have a northern aspect or strong winds.
Specialist planting- Border carnations and pinks
Many gardeners like to specialize in a particular species of plant. Carnations and Pinks are ideal for an herbaceous border and the smaller plants make good rockery plants. They are extremely hardy and suitable for most areas, although do tend to become straggly and are best treated as biennials.
This is not a problem as propagation is very simple. Layer carnations and take cuttings from the pinks in the spring, providing you with a continuous supply of new, fresh plants.
These plants thrive in various soils, as long as it is well drained and non-acid. They prefer a sunny position.
Prepare the soil by digging in plenty of organic matter and let it settle for a month before planting. Add a dressing of lime or ground chalk and hoe this in.
Carnations can grow up 65cm (2ft) high. Dead head regularly and keep a check on aphids.
This is not a problem as propagation is very simple. Layer carnations and take cuttings from the pinks in the spring, providing you with a continuous supply of new, fresh plants.
These plants thrive in various soils, as long as it is well drained and non-acid. They prefer a sunny position.
Prepare the soil by digging in plenty of organic matter and let it settle for a month before planting. Add a dressing of lime or ground chalk and hoe this in.
Carnations can grow up 65cm (2ft) high. Dead head regularly and keep a check on aphids.
