Trees And Shrubs

Question 1

Definition of a tree

Answer 1

Woody plant
Usually one main stem or trunk
Usually quite large
Suitable for domestic garden at no more than 10m

Question 2

Trees for winter interest

Answer 2

Acer griseum - deep copper bark that lifts like sheets of paper
Prunus serrula - beautiful bark

Question 3

Trees for autumn interest

Answer 3

Acer griseum
Amelanchier x grandiflora ‘ballerina’
Cercis canadensis ‘forest pansy’

Question 4

Shrub definition

Answer 4

Woody plant
Often with several stems or a very short single stem
Not normally very large

Question 5

Winter interest shrubs

Answer 5

Cornus alba 'sibirica' 
Daphne bholua (fragrant flowers)
Hamamelis x intermedia (very fragrant flowers)

Question 6

Autumn interest shrubs

Answer 6

Euonymus alatus (leaf colour)
Callucarpa bodinieri (violet berries)
Clerrodendrum trichotomum (unusual berries)
Rhus typhina (leaf colour)

Question 7

Function and role of woody plants

Answer 7

To add height
To add permanent structure
Create shelter and shade
Year round interest
Visual and noise barriers
Wildlife
Dust pollution filtering
Focal points

Question 8

Effects can provide

Answer 8

Flower
Fruit
Bark colour
Leaf colour
Autumn colour
Shape
Texture 
Form

Question 9

Disadvantages of woody plants

Answer 9

Undesirable shade
Can grow too big in time
Roots can damage buildings
Competition with other plants
Production of debris (leaves and fruits)
Cost of maintenance

Question 10

Types of tree to buy

Answer 10

Bare root or container grown
Most native trees ate field grown
Most ornamentals are container grown.
Evergreens and conifers are more suited to growing in containers, unless for commercial timber production.

Question 11

Classification of trees in the nursery trade

Answer 11

Name.                 Overall height
Seedling              variable
Transplant.          20-40cm
Whip.                     60-90cm
Feathered whip.  150-180cm
Half standard.      175-250cm (125-150cm stem)
Standard.               275-300cm (150-180cm stem)
Heavy standard.   300-360cm

Question 12

Seedling and transplant

Answer 12

Seedling is the end of a trees first season.

Transplants have been potted up or lined out in the nursery to grow for a further year.

Question 13

Whip

Answer 13

Single stemmed young tree which have yet to develop side branches.
Common for native trees as cheap to produce and shape of tree is usually less important.
A whip will grow side shoots as it grows and if sold with these it is known as a feathered whip.

Question 14

Standards

Answer 14

Have had all the laterals removed in the nursery to create a clear stem. This is considered a more desirable shape for a tree, but some growers prefer to leave feathers on as long as possible as it produces a stronger trunk in a mature tree.

Question 15

Role of shrubs

Answer 15

Mixed borders
Shrub borders
Focal points
Hedging
Containers

Question 16

Planting a shrub border

Answer 16

Large shrubs should go at the back, or in the middle for an island bed
Try to get lots of contrasting colour, texture and form in the bed and consider the use of repetition to create unity.
Designs can be marked out with silver sand prior to planting.
Pleanting us best carried out in autumn to enable roots to settle in over winter, but anytime from nov-mar is acceptable, avoiding frost.
Once planted it should be mulched with good layer of organic matter e.g. well rotted manue, garden compost or bark chip which is more attractive.

Question 17

Soil preparation

Answer 17

If planting in spring begin prep in autumn, especially in heavy soils since any large lumps will be broken down in winter frosts.
Remove perennial weeds.
If area is overgrown, cut down the vegetation and dig out the root.
Regrowth from remaining roots should be dug out as soon as the appear or use a weedkiller.
Once clear dig in lots of organic matter to improve moisture retentio. And increase soil nutrient content.

Question 18

Planting a container grown tree or shrub

Answer 18

Place container in water for at least 30min before planting.
Mark out an area 3-4 times the diameter of the pot.
Remove any turf or weeds from the surface and dig a hole 1.5 times the pot depth.
Using a fork break up the soil at the base and side of the hole to enable roots to penetrate more easily.
Lay plant on its side and carefully slide it out of the container.
For trees insert stake firmly, slightly off centre, towards the direction of the wind, at an angle of about 45 degrees.
Add about 1/5 of the topsoil into the hole.
Place plant in the hole and use a cane to check the top of the root ball is level with the soil.
Backfill with the rest of the soil and organic matter, firming evenly by treading.
For trees tie to stake.
Water, mulch and cut back any damaged shoots.

Question 19

Planting bare root trees and shrubs

Answer 19

As for containers but make the hole just wide enough to take the roots when spread out.
Cut off any damaged roots before planting.
Drive in a stake then make a small mound of loose soil in the centre of the hole.
The stake can be vertical as its not going to damage the roots.
Place the plant on the mound and spread the roots round the stake.
Use a cane to line the soil mark on the stem so it is flush with the surrounding soil.
Gently firm in.
Water and mulch.

Question 20

Lime hating trees and ahrubs

Answer 20

Camellia japonica
Rhododendron spp
Leptospermum scoparium
Gaultheria mucronata

Question 21

Weed control in a shrub border

Answer 21

Good eradication before planting
Maintain a good depth of mulch
Control perennial weeds by digging out or spot spraying.
Annual weeds can be hoed or covered with mulch.

Question 22

Watering a shrub border

Answer 22

Water during dry spells in first season

In later years unlikely waterig will be required.

Question 23

Pests and Diseases of woody plants

Answer 23

Aphids
Powdery mildew
Cankecoral spot
Honey fungus

Question 24

Pruning tools

Answer 24

Pruning saws - slightly curved blade and cut on the pull stroke.
Bow saws with narrow end are easier to work between branches.
Chainsaws - need trained operator. Poe required
Long handled pruning saw better for at height
Secateurs
Loppers for thicker branches

Question 25

Reasons for pruning

Answer 25

Create a desirable shape
Control size
Improve ornamnlental display - some shrubs only flower on youngest growth, some a grown for young stems
Remove weak and damaged growth
Remove crossing or low branches
Thin out dense growth
Remove dead, diseased, damaged and atypical growth e.g. remove non variegated growth in a variegated plant.

Question 26

Formative pruning

Answer 26

Plant pruned early in its life to ensure it achieves the correct shape.

Question 27

Routine pruning

Answer 27

Carried out every year to achieve best results

Question 28

Renovative pruning

Answer 28

Carried out on shrubs that have been neglected.
Normally involves removal of large amounts of material.
Should be carried out in dormant season and care taken to spread the process over 2 or 3 winters, especially for species that don’t respond well to pruning

Question 29

Science behind pruning

Answer 29

Buds normally produce a hormone that suppresses the growth of buds around them by drawing a disproportionate amount of sap towards the dominant bud.
The terminal bud is always dominant.
When a but us removed by pruning it breaks the apical dominance and allows other buds to grow vigorously.
A reduction in spa flow can also be done by bending a dominant bud into the horizontal. This reduces sap flow the the apical bud and allows laterals to develop.
This technique is used for climbing roses and espalier fruit.

Question 30

When to prune

Answer 30

Renovative and formative pruning should be do e in dormant season - Nov to march.the time of year for routine pruning depends on when the shrub flowers.
As a rule those that flower early produced their flowers on wood grown in the previous year and should be pruned after flowering.
Those shrubs which flower from summer onwards usually produce their flowers on current seasons wood and should be pruned in late winter.
Many shrubs require no pruning at all e.g. most evergreens.

Question 31

Wound dressing

Answer 31

Traditionally wound dressing or pruning paint was only used in cuts larger than 2.5cm diameter.
Scientists have now found that wound dressings are strictly cosmetic and have little to do with preventing disease.
Pruning paint may slow down the healing process
In general wound dressing isn’t recommended.