Herbaceous Perennials Flashcards
What is a herbaceous perennial?
A plant that lives longer than three years and never forms wood.
Some are evergreen, some die back to ground level each year and regrow the following spring.
List garden uses for herbaceous perennials.
- Herbaceous borders
- Borders for cut flowers
- Cottage gardens
- Knot gardens
- Bog gardens
- Mixed borders with bulbs and shrubs
- Woodland gardens
- Herb gardens.
What is a bed and what is a border?
- Beds are planted areas which can be viewed from all sides. When placed in isolated in the middle of grass they are called island beds
- Borders are planted areas that have a barrier e.g. a wall or hedge on one side so they can only be viewed from the front or each end.
What are the disadvantages of a traditional herbaceous border?
- Bare and uninteresting during the winter and only at best for a relatively short period of time
- Large number of tall plants required for the back of the border, these require staking
- If backed by a hedge supplementary feeding may be necessary
- Very labour intensive, requiring regular weeding, feeding, deadheading, and pest and disease control. Every 3 - 5 years plants need lifting and dividing
- Hedge requires regular clipping so space must be left for access
- Airflow across border is poor so fungal diseases such as mildew could build up.
What are the advantages of island beds?
- Can be cut to any shape, out of lawn, or a paved/gravel area
- Can we viewed from all sides
- Fewer taller plants are used, less staking
- Access is easier for weeding and deadheading
- Plants do not become drawn and remain compact
- Air moves across beds more freely so diseases may be less of a problem.
What are the disadvantages of island beds?
- There is no wall or hedge to provide shelter or act as a visual backdrop
- If beds are in grass, regular edging maintenance will be required
- Often no paving or path around the beds so plants cannot flor over and break the hard edge
What are the advantages and disadvantages of a mixed border?
Advantages
- Mix of plants which may reduce labour costs as other plants require less maintenance than HPs
- HPs do not provide sufficient year-round interest so shrubs and other plants grown with HPs provide extra colour and interest
- Shrubs are used to give structure
- Flowering and fruiting trees can provide interest in winter and spring
- Shrubs grown for foliage can be an effective foil or backdrop
- HPs provide colour and interest at times shrubs etc may not be so interesting.
Disadvantages
- Mixed borders can be difficult to plan
- A range of skills are needed as trees and shrubs have to be pruned
- Mixed borders may suffer from trying to look interesting at all times of the year.
What are the considerations when selecting a site for a bed or a border?
- Soil must be fertile, well drained, moisture retentive and have plenty of organic matter
- Should be free of perennial weeds, pests and diseases
- Site must be sunny and open, away from overhanging trees
- Site should be sheltered from wind.
When is the best time to plant herbaceous perennials?
In autumn or spring.
Those which flower in spring or early summer are best planted or divided in the late autumn.
Describe some considerations when planning a herbaceous bed or border?
- Size. Beds and borders must be in scale with the size of the garden and the size of any buildings. To have impact they should be wide enough for several rows of different plants. In a border he maximum height should not exceed the width of the border; in a bed the maximum height should not exceed half the width of the bed.
- Colour schemes. One colour or a mix; contrasting, harmonious, etc
- Season of interest. Concentrate on flowering over a short season or a longer season?
- Maintenance. Including fertilisation, weeding, staking, division, irrigation, deadheading, pests and diseases, mulching.
Describe the fertilising of herbaceous borders.
Annual application in Spring of a balanced fertiliser such as Growmore at 100g/sqm or blood fish and bone at 70g/sqm.
Describe staking of herbaceous borders.
Best carried out before it’s required. Materials range from peasticks or hazel coppice to bamboo canes to metal or wire supports. Should be unobtrustive (15-30cm shorter than the final height of the plant).
What pests and diseases commonly affect herbaceous borders?
Aphids, slugs, snails, vine weevil, grey mould, powdery mildew, stem and bulb eelworm.
Name five HPs for groundcover
- Stachys byzantina
- Geum ‘Totally Tangerine’
- Geranium sanguineum
- Ajuga reptans ‘Atropurpurea’
- Ophiopogon planiscapus ‘Nigrescens’
- Alchemilla mollis
- Lamium maculatum
Describe the symptoms of two diseases affecting herbaeous borders: powdery mildew and grey mould.
Powdery mildew
Produced white, dusty spreading patches of the fungus on the upper and lower surfaces of the leaf, flowers and buds.
Plant tissue can become stunted and distorted. Infection can causes plants to turn a purple colour.
Grey mould
A fuzzy grey-brown mould affecting soft plant tissue, leaves and flowers.
Spreads rapidly in high humidity.
Causes a slimy rot and death of the plant.
