Copy R2112 3.9 Maintenance of Woody Plants Flashcards
1
Q
Name general maintenance activities of shrubs
A
- Watering (especially trees, 2 – 3 years)
- Feeding (spring-flowering shrubs after pruning and summer-flowering shrubs as they begin to grow in spring)
- Weeding
- Mulching – annually
- Check ties, stakes & protection – annually
- Check for pests and diseases – check at least twice a year
- Pruning
2
Q
Watering
A
- Regular intervals
- In dry weather the soil should be really soaked well
- Adapted to weather conditions and the amount of rainfall
- A large standard may need about 30 litres
3
Q
Weeding, will depend on…
A
Generally, more open areas are more prone to weed growth.
- Soil – the more fertile the more weeds
- Season – warm weather means more weeds
- Condition of the site when planted – that’s why ground preparation is so important
- Size of trees and shrubs when planted – the smaller the trees or shrubs the more weed control is needed
- Shade tolerance of trees or shrubs – some shade trees or shrubs can tolerate more weed growth
A certain amount of weed growth can be good though as it protects trees from drought particularly clay soils (here mulch will help), sun scorch and drying winds. It is a fine balance. Brambles, nettles which are sparse weeds can protect trees from drying winds and damage from deer and vandals. This does require periodic checks, through.
4
Q
Weeding methods
A
Hand weeding:
Using short-handled grass hook (care required so no damage to roots) or can simple hand pull. Labour intensive so only suitable for small schemes.
Mechanical weeding:
Strimmer or brush cutter. Care required! As can result in strimmer damage – ring barking. Strimmer guards.
Motor scythes – mounted on two wheels, the cutting mechanism a knife or rotating blades, the operator walks behind the machine.
Tractor-mounted machines with flails or tractor-towed rollers or breaking bars.
It can be argued that regular mowing or strimming merely aids the spread of grass species and makes moisture and nutrient deficiencies even worse. Mown grass can be viewed as more damaging than long grass.
Herbicides:
Usually applied as a spray. Environment impacts and health issues. Strict regulations for use. Training required for using professional products. Correct dosage and required weather conditions. PPE requirements.
5
Q
When do you need to weed?
A
- Competition from weeds greatest in May and June
- Timing will vary, depending on method of control, locality, weather conditions and season
- Herbicides must be timed according to type of herbicide, amount of growth and weather
6
Q
When should tree stakes and ties be adjusted?
A
- Depends on the species and site conditions.
- Must be tested every year until it is safe to remove.
- Remove ties after 18 months to 2 years, at an absolute maximum of 3 years.
- If a guard is to be used then the tie will need to stay, to prevent rubbing.
7
Q
Monitoring the health and establishment
A
- 1–2 times a year: start/end of growing season
- In winter you may check for animal damage (rabbits, deer)
- In the autumn you may be checking for diseases such as honey fungus as this is when the fruiting bodies are evident
- P & D
- Environmental factors:
- frost
- shade
- drought
- water-logging
- high/low temperature damage
- soil pH including the symptoms of lime-induced chlorosis
8
Q
Pest and diseases affecting trees and shrubs
A
- Aphids
- Powdery mildew
- Rose blackspot
- Coral spot
- Canker
- Honey fungus
9
Q
Aphids
A
What happens:
- Incomplete lifecycle (egg, nymph, adult). Very rapid.
- Sometimes the female (often wingless) can produce live young without the egg stage and without fertilisation. (Sexual reproduction occurs in autumn when eggs are needed.)
- Damage to crops is similar for nymph and adult and is caused by the piercing (stylet) mouthpart. This tubular mouthpart pierces the plant until it reaches the phloem to extract the sugary contents. Known as slurpers.
- The soft young parts of plants are more likely to be attacked.
- Milked by ants for honeydew.
- When plants are infested, shoots become distorted and plants are weakened.
Controls:
- Pinch out any young growth that shows minor infestation.
- Can be wiped off by hand or gently hosed with water is it if a minor infestation.
- Plants to attract beneficial insects may also be useful to help maintain a natural balance. Such as capsids, ladybirds, ladybird larvae and birds.
- Plant oils which block the spiracles of insects.
10
Q
Powdery mildew
A
- A number of fungi can produce a white powdery growth on leaves. Affects epidermal cells – therefore a surface problem.
- Starts on upper leaf surface and may spread to lower surface if severe as well as other plant parts above ground
- Distortion common on young growth, foliage may yellow and die
- Fungal spores are produced which are spread by water splash and air currents – avoid watering leaves of plants
- Encouraged by dry soil conditions and humid air
Controls:
- Mulch to retain moisture
- Regular irrigation, avoiding splashing foliage
- Improved air flow, good air circulation.
- Selection of resistant cultivars
- Cut out damaged/infected material
- Avoid growing near to base of walls
11
Q
Honey fungus
A
- Attacks the roots of woody and perennial plants, can lead to plant death. Can be very rapid or very slow.
- A white fungal growth can be seen between the bark and the wood at ground level, occurs in the soil as well.
- Die back occurs in the upper parts of plants, particularly in hot weather. Plants may have smaller leaves and fail to flower. Some will display early autumn colour, cracking or resin at the base of the trunk.
- Rhubarb is a good indicator plant of the presence of the disease.
- Spreads through bootlaces (rhizomorphs) and spores from fruiting bodies in spring and autumn
- In autumn, honey-coloured toadstools may appear, the spores produced are not considered the main source of infection.
- Difficult to eradicate
- Often establishes on newly planted trees and shrubs that are planted too deeply.
Controls:
- Select resistant plants. Trees such as Taxus, Juglans nigra, Quercus, Buxus are more resistant; susceptible plants include Syringa, Betula, Malus, Viburnum, Rosa, Rhododendron
- Dig out and dispose of infected plants, clearing away all the stumps and infected material
- Do not use freshly processed woodchip where honey fungus is found on site
- Use vertical physical barriers in the soil such as butyl rubber sheets
12
Q
Rose black spot
A
- A f_ungal disease_ common on roses. Causes purple/black spots and yellowing on leaves. Spots may enlarge and join up, causing defoliation.
- Overwinters in stem lesions, bud scales and fallen leaves.
- Spores will then re-infest the following spring.
- Spread by rain splash mainly.
- ‘Iceberg’ susceptible.
Controls:
- Hygiene is important, clearing away fallen leaves and pruning aimed at stems with lesions, use of mulches
- Avoid excessive fertilisers as sappy young growth attracts infection
- Resistance not common in rose cultivars but there are some, such as Rosa ‘Bonica’, Rosa rugosa
- Can use fungicides, however, resistance common
- Allow adequate spacing between plants
- Can use plant-oil extracts such as tea tree oil
13
Q
Coral spot
A
A disease caused by a fungus. Often found on dead material which is why it is important to cut out dead material by pruning.
Symptoms:
- Branches die and develop pinhead-sized coral-pink fungal pustules. Any time of year.
- It causes die-back of branches of woody plants, but the causal fungus is a weak pathogen and its presence often indicates that the plant also has other problems.
- It is rarely found on conifers.
Non-chemical control:
- Prune in dry weather.
- When carrying out routine pruning, cut branches through the collar (ring of slight swelling found at the base of branches). Healing of wounds occurs most quickly here, compared to leaving stubs (snags) or cutting flush with the bough or trunk.
- If die-back occurs after pruning, remove dead material to avoid further infection.
- Prune out infections promptly and cut back to healthy wood. Do not leave dead wood to moulder and generate spores in damp corners of the garden.
Chemical control:
- There are no specific fungicidal controls for this disease.
- Wound paints are not recommended for routine use as they are thought to interfere with healing and may even provide a better environment for rots.
14
Q
Apple and pear canker
A
- Fungal disease.
- Cankers are round or oval areas of dead, sunken bark, often starting at a wound or bud.
- On small branches, cankers may girdle the stem and kill it in a single season.
- On larger branches, cankers are perennial, with the affected area covered with dead bark that shows concentric rings indicating periods of active spread. Older cankers lose the bark, exposing dead wood in the centre.
- Poor shoot growth; wood can fracture in high winds
- Spreads mainly by wind blowing the spores in spring; enters through leaf scars in autumn or pruning wounds in winter. Small red fruiting bodies.
- It is a dry canker as there is no oozing. Hence a fungus.
- On fruit: Developing fruits are sometimes attacked, and will rot and fall.
Controls:
- Grow resistant cvs. Such as ‘Sunset’, ‘Grenadier’
- Avoid pruning susceptible apple cultivars such as ‘Cox’s Orange Pippin’ in damp conditions as it spreads by rain splash
- When it has taken hold, the affected areas must be cut out
- Removed material should be burnt
15
Q
Prunus bacterial canker
A
- A disease of the stems and leaves of Prunus, especially plums and cherries, but also apricots, peaches and ornamental Prunus species.
- It causes sunken patches of dead bark and small holes in leaves, called ‘shothole’, often with stem cracking and a light brown gum exudate.
- Angle between branches most common site of infection.
Controls:
- Use of resistant rootstocks and scions
- Cut out cankered areas
- Prune cherries straight after flowering (!)
