Plant Specification

Jump to each topic by clicking on the relevant box below

Define the term aspect

From which direction does the sun rise? East

Explain the typical discrepancy between the location of a garden boundary fence and its aspect. Assume the boundaries run parallel with N/S, E/W.

In this example the fence located on the north side of the garden (running E-W) has a south facing aspect (if one stands with their back to this wall they are facing south). Conversely, the fence located on the south side of the garden (running E-W) has a north facing aspect.

The fence located to the east of the garden (running N-S) is west facing and the western fence (running N/S) has an east facing aspect.

What aspect is commonly recommended for ferns? North facing (receives no direct sun)

Why might a west facing aspect receive no sunshine? If it's shaded by tall buildings or evergreen trees to the south and west

In which direction does the sun set? West

Which aspect is most suitable for sun loving plants? South facing (receives sun all day)

What is a rain shadow? A location that is protected from rainfall and and has, on average, drier soil than unprotected areas. For example: - Soil beneath the eaves of a house roof, - To the north east of a building where rain angled by the prevailing south westerly winds is partially blocked by the building

1. For each compass point state sunlight related factors that affect microclimate.

2. Compare how each aspect (N/E/S/W) affects soil conditions during hot, sunny weather.

N

W

E

S

What two main factors lead to a planted area's soil becoming dry in hot, sunny weather? - Evaporation of water from the soil surface and upper soil layer - Transpiration (from plants) leading to water losses from the topsoil and subsoil

Q1 and Q2 Answers:

North 1. Does not receive direct sun, therefore cooler through the day. 2. Soil drys more slowly because of cooler conditions compared to other aspects.

East 1. Receives morning sunshine, meaning it warms more quickly in the morning. This can result in rapid frost melt on cold, sunny winter mornings. Cooler in the afternoon than south or west facings. 2. Soil remains cooler as it's shaded during the hotter afternoons, so dries more slowly than south or west facing sites. It will dry faster than north facing sites.

South 1. Receives full sun all day, resulting in a hotter microclimate than other aspects. 2. Due to direct sunshine throughout the day, south facing sites' soil dries the fastest of all aspects.

West 1. Receives afternoon sunlight, becoming hottest in the afternoon. Remains cooler through the morning. Frost is slower to thaw in cold weather. 2. Hot afternoon conditions means the soil dries faster than north and east facing sites, but a little slower than south facing sites.

In the soil adjacent to a house, which aspects receive the most and least rain? Soil adjacent to south and west aspects receive the most rain (because the prevailing southwesterly winds blow rain at an angle). Soil adjacent to north and east aspects receive the least rain (they are in a rain shadow due to the typically southwesterly direction of rain)

An open, unshaded site has most in common with which aspect? Open, unshaded sites share most commonality with south facing aspects, receiving full sun all day.

Each number relates to a specific word, so if you think (1)________ is 'bananas' then if (1)________ appears later on in the passage, 'bananas' is the missing word.

Topography relates to the lie of the land, such as (1) s________, (2) h________, (3) f________ areas, (4) t________ etc. The direction a (1) s________ or (4) t________ faces is referred to as its (5) ________ and impacts the amount of (6) ________ it receives. This impacts the microclimate, for example a (7) ________ facing (1) s________ receives sun all day and is warmer than a (8) ________ facing (1) s________.

Water drains down a (1) s________, meaning the higher areas become (9) ________ first, and the lower areas remain (10) ________. In addition, (11) ________ air sinks down a (1) s________. If there is a wall or gapless fence at the base of a (1) s________, (11) ________ air gathers and creates a (12) ________ ________. This also happens with (2) h________.

When there is heavy rain on a (1) s________ it can lead to runoff which can cause (13) ________ erosion, leading to loss of valuable top (13) ________.

Topography relates to the lie of the land, such as (1) slopes, (2) hollows, (3) flat areas, (4) terraces etc. The direction a (1) slope or (4) terrace faces is referred to as its (5) aspect and impacts the amount of (6) sunlight it receives. This impacts the microclimate, for example a (7) south facing (1) slope receives sun all day and is warmer than a (8) north facing (1) slope.

Water drains down a (1) slope, meaning the higher areas become (9) drier first, and the lower areas remain (10) wetter. In addition, (11) cold air sinks down a (1) slopes. If there is a wall or gapless fence at the base of a (1) slope, (11) cold air gathers and creates a (12) frost pocket. This also happens with (2) hollows.

When there is heavy rain on a (1) slope it can lead to runoff which can cause (13) soil erosion, leading to loss of valuable top (13) soil.

Hint: the missing words in a random order hollow, sunlight, cold, south, soil, frost pocket, aspect, drier, north, terrace, slope(s), wetter, flat, aspect

Extra Hint: (1) slope(s)

Extra Hint: (2) hollows

Extra Hint: (3) flat

Extra Hint: (4) terrace(s)

Extra Hint: (5) aspect

Extra Hint: (6) sunlight

Extra Hint: (7) south

Extra Hint: (8) north

Extra Hint: (9) drier

Extra Hint: (10) wetter

Extra Hint: (11) cold

Extra Hint: (12) frost pocket

Extra Hint: (13) soil

Define the term 'exposure' in relation to gardens

State the factors that lead some sites to be more exposed than others

Factors affecting exposure:

Exposure to wind:

- Sites that are buffered from wind are less exposed. This can be due to a deliberately planted shelter belt, including hedgerow(s), or nearby tall plantings such as woodlands. Buildings can also create shelter such as in urban areas, as can open boarded fences that break up winds.

- Wind buffers: are best placed to the south west of a site where they reduce exposure to the prevailing southwesterly winds, though a wind buffer on all sides is most effective for holistically reducing wind exposure.

Light:

- Sites that are south facing or in the open experience more exposure to light than north, east or west facing sites. East and west facing sites receive more exposure to light than north facing sites.

- Sites that are shaded by vegetation, such as under trees or shrubs, experience less exposure to light. In summer all sites beneath tall vegetation are less exposed to light. Under deciduous trees and/or shrubs, there is more exposure to light in winter.

1. What is a wind tunnel?

2. What can cause a wind tunnel to occur?

Explain the impact of wind on soil water content during summer.

Wind increases the rate at which moisture is lost from the soil. There are two main ways that soil water is lost at a higher rate due to wind:

Evaporation:

- Water evaporates from the upper soil layer into the air above the soil, which becomes more humid. The humid air is blown away from the soil surface, meaning humidity remains lower near the soil surface than without wind.

- This increases the rate of diffusion of water vapour from the upper soil layer into the air above the soil, increasing evaporation of soil water.

- This causes the soil to lose moisture faster.

Transpiration:

- Water vapour diffuses out of stomata into the air outside the leaf, making external air near the stomata more humid.

- Wind removes humidity from around the leaf, meaning the air around the leaf is lower in humidity than without wind.

- This maintains a steeper concentration gradient between the higher water vapour concentration inside the leaf's air spaces and lower concentration outside the stomata.

- Therefore there is a constant higher rate of diffusion of water vapour from inside the leaf through stomata to outside the leaf (transpiration).

- To replace water lost from inside the leaf the transpiration stream moves at a higher rate, bringing water from the roots.

- This means water is removed from the soil at a higher rate to supply the transpiration stream, increasing the rate of soil drying due to wind.

What are the impacts of high wind speed wind in an orchard?

High wind speeds in an orchard can break branches and damage or break off leaves. This provides entry points for pathogens such as apple canker or bacterial canker on some Prunus sp. such as cherries and plums.
High wind speeds can damage or blow off flowers, reducing crop yield.
High wind speeds prevent pollinators from flying. If persistent or regular high wind coincides with flowering, pollination is limited. This will reduce fruit set and therefore yield.
High wind speeds reduce the potential for warming in an exposed orchard, meaning fruit development and ripening can be delayed, resulting in later harvests.

How can horticulturalists minimise the negative impacts of heavy wind in an orchard?

Orchards benefit from a shelter belt to buffer and break up heavy winds. As the prevailing wind is from the south west, a shelter belt is best situated to the south west of the orchard. Ideally the shelter belt should have a high proportion of evergreen species, such as Ilex aquifolium or Taxus baccata as these will buffer wind in spring when the orchard trees are flowering, meaning pollination will be more successful as pollinators will be more active. A high proportion deciduous wind break is less effective in spring when it's not yet in leaf.

Trees should be carefully pruned to remove congested growth and maintain a suitable height. If branches are spaced there's a lower risk of them rubbing or colliding when wind blows. Lower height trees are less exposed to strong winds and more easily protected by a shelter belt.

The garden depicted below is on a loam soil. Complete the following labels:

1. For the letters A - D, name the facing for each boundary

2. For the letters E - I, name the expected microclimate factors. For example, E would be full sun, dry summer soil

A South facing

B West facing

C North facing

D East facing

E Full sun, dry summer soil

F Semi-shade: afternoon sun. Soil liable to dry in summer.

G Dry shade

H Semi shade: morning sun. Soil likely to remain damper in summer.

I Full sun, dry summer soil.

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What is hardiness? The ability of a plant to withstand cold

Why is provenance relevant to hardiness? The locality a plant was originally collected (seeds or vegetative material) within its natural range will affect its hardiness. Plant species typically occupy a range of geographical spaces with some variation in microclimate. Those from colder parts of the natural range will have genetics to better survive cold. Therefore individuals from colder provenances are preferable to maximise potential hardiness in the British climate.

Complete the following RHS hardiness zones. The first (H7) is done for you:

H7: very hardy, can tolerate below -25°C without damage

H6:____________________ hardy – minimum -20 to -15°C

H5:____________________ hardy – minimum -15 to -10°C

H4: ____________________ hardy – minimum -10 to -5°C

H3: ____________________ half-hardy/unheated glasshouse - minimum -5 to 1°C

H2: ____________________ tender/cool glasshouse – minimum 1 to 5°C

H1C: ____________________ warm temperate/heated glasshouse – minimum 5 to 10°C

H1B: ____________________ subtropical/heated glasshouse – minimum 10 to 15°C

H1A: ____________________ tropical/heated glasshouse – minimum above 15°C

Why might F1 hybrid seeds be preferred over open pollinated seeds?

What qualities might be prioritised when selecting herbaceous perennials for a windy site?

How can the selection and use of plant supports be more sustainable?

Plant supports can utilise woody prunings of on-site plants, for example growing a hazel coppice to provide plant supports. This eliminates the carbon footprint of buying in stakes.

Flexible hazel coppice can be woven into a supportive matrix staking, reducing or eliminating the need to use garden twine, which has a carbon footprint from manufacture and transport.

After use the stakes can be used in bug hotels or composted. This creates habitat for wildlife. As it is decomposed it provides a food source for detritivores and decomposers such as bacteria and fungi, benefitting soil biodiversity.

What is the expected outcome of planting a shade-suited plant in full sun?

What is the expected outcome of planting a species that requires full sun in a shady location:

How does soil texture relate to plant selection?

The proportions of sand/silt/clay in a soil impact the soil's water and nutrient holding capacity, and aeration.

A sandy soil drains quickly and is likely to become dry in summer, and unlikely to be waterlogged in winter. It's only suitable for plants that tolerate dry summer soil, such as mediterranean climate plants. In contrast, soils high in clay are less likely to become dry in summer but can become waterlogged in winter. They suit plants that need damp soil and tolerate wet winter conditions.

Plants must be selected to suit the soil conditions. This maximises the likelihood of maintaining optimal plant health. Plants unsuited to the soil conditions will experience a decline in health and will perform poorly in the garden.

1. What does AGM stand for?

2. How does the AGM relate to plant selection?

1. What does AGM stand for?

Award of Garden Merit

2. How does the AGM relate to plant selection?

AGM plants have been trialled for three years during which they're subject to ongoing assessment against key criteria by an expert panel. Plants that perform best - for example by being floriferous, self-supporting, resistant to pests and pathogens, etc. - gain the AGM. Therefore, AGM species or cultivars are likely to be reliable garden performers and are often prioritised in plant selection.

What are the advantages and disadvantages of using cultivars in plant selection?

Cultivars.

- Advantages:

Clonal plants so they have identical traits, such as flower colour, growth habit, resistance to pests or pathogens, tolerance of certain soil types, hardiness, etc.

This predictability is useful in selecting plants to maximise plant health and in garden design for specific qualities such as flower colour or timing.

- Disadvantages:

Cultivars are clones, meaning there is no genetic variation. If a new pest or pathogen (including a new strain of an existing pest or pathogen) occurs and the cultivar is not resistant, every individual will be susceptible and decline in health.

Cultivars in the same microclimate generally flower at the same time compared to genetically varied individuals of a species or hybrid. This reduces the time nectar forage is available to pollinators.

Some cultivars produce double flowers which are not accessible to pollinators, reducing their biodiversity value.

Some cultivars are sterile and do not produce seed, reducing potential food for wildlife, which does not benefit biodiversity.

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1. Annual

2. Biennial

3. Deciduous herbaceous perennial

4. Evergreen herbaceous perennial

5. Deciduous shrub

6. Evergreen shrub

7. Deciduous tree

8. Evergreen tree

A. Creates a sequence of interest every year from emergence in spring to flowering in summer. Tawny, dead winter stems catch frost, offering additional interest.

B. Useful for creating privacy all year round as a boundary hedge.

C. Easy to start from seed but only flowers in the second year. Often self-sow, creating seasonal interest.

D. Useful for creating a green ground cover throughout the year, for example under deciduous trees or in sunny, exposed sites.

E. Can be used to quickly fill in gaps in borders from direct sowing, with flowers later in summer. Also used in spring sown meadow mixes for colour the same year.

F. Creates structure and a focal point in a lawn with a clear trunk, leafy summer interest and autumn colour.

G. Useful for screening tall eyesores or blocking views into a garden from neighbours upstairs windows.

H. Provide year-round structure in a garden and particularly useful in winter when their bare stems create taller interest.

Answers 1: E 2: C 3: A 4: D 5: H 6: B 7: F 8: G

Plants must be carefully considered before they're specified for inclusion in a garden.

Match the plant lifecycle to its justification:

From the above plant categories (1 - 8), which cannot be purchased as a cultivar?

State the disadvantages of including a large evergreen shrub in a garden.

Why can woody plants can gain greater nutrition and water from a patch of ground than annual plants?

A client wants to plant Quercus robur (English oak) in their medium sized suburban back garden. What needs to be considered before a decision is made?

Quercus robur will eventually become a large tree. In a medium sized suburban garden this is likely to be out of scale with the garden and cast more shade than the client (and future residents) desire. Over time, planting schemes in the garden will need to be adjusted as the oak grows larger and shades sun-loving plants. These will need to be moved and replaced with shade tolerant plants. This is time consuming and expensive as new plants are purchased. Whilst the oak is sequestering carbon, some of this benefit will be offset through the production and transport of new plants to the garden.

Neighbours may not want a large tree shading their garden.

In some parts of the UK oak processionary moth is present (and the pest is spreading each year). The caterpillars can be very dangerous to animals, including people, when they expel irritant hairs if disturbed. This is a major hazard in gardens where people are in close proximity to the tree. Regularly scouting for the caterpillars is time consuming and treatments have a negative impact on biodiversity.

Herbaceous (non-woody) plants include: ephemerals, annuals, biennials and herbaceous perennials.

Which is the most sustainable option for a garden? Justify your answer.

Herbaceous perennials are the most sustainable option. Unlike ephemerals, annuals or biennials, herbaceous perennials don't need to be replanted/replaced because they each have organ(s) of perennation from which they regrow each year. This reduces the carbon footprint of producing, packaging and transporting seeds for shorter lived plants every year. Herbaceous perennials can be grown from seed (just once unlike shorter lived plants), meaning they can have a low carbon footprint to produce. Their roots and stems persist through winter and if densely planted they can reduce soil erosion that can result from heavy rainfall. Ephemerals and annuals are less effective at this in winter.

Why might woody plants be used for hedging within a garden?

Climate change is leading to hotter heatwaves in summer, making gardens less appealing for recreation and relaxation. How can gardeners address this through plant selection?

Trees are an effective way to reduce the build up of heat in a garden during hot weather. Trees shade the ground, reducing heat. They also transpire, which has a cooling effect. In combination they can effectively prevent excess heat developing in gardens during hot weather.

Planting an understory of shrubs and herbaceous ground cover adds additional transpiration, further cooling gardens.

If trained over a pergola, climbers also create shade along with the cooling effect of transpiration.

How can new plants be introduced to a garden with minimal biosecurity threat?

The lowest risk way to introduce new plants is via seed, as this is highly unlikely to have pests or pathogens.

Other lower risk ways are to source new plants via cuttings or division from neighbouring gardens (with permission), or to purchase plants from a local nursery who propagate their own plants on-site or nearby. This reduces the risk of biosecurity threats from far away locations being introduced. All new plant material should be checked for pests or disease before removal/purchase.

If possible new plants should be purchased bare root. This reduces the risk of new pests or pathogens being introduced in growing media.

All new plants should be quarantined for at least three weeks before planting.

1. Potted

2. Bare root woody plant

3. Bare root herbaceous plant

4. Rootballed/burlap

A. Cannot be used for evergreen plants of this type.

B. It's important to ensure the crown of this type of plant is planted to the correct depth depending - this varies by plant species.

C. They have soil (not compost) around their roots

D. Usually in plastic which is unsustainable.

E. Plants can most easily be quarantined after purchase.

F. These are dug up and wrapped to order during the dormant season.

G. Includes all bulbs, such as those that are purchased loose in bags.

H. Common for roses and fruit trees.

I. A common way of obtaining large woody specimens without the risk of circling woody roots.

J. Material used to contain the roots can usually be reused to containerise other plants.

K. You can inspect the root system and to ensure there are no circling roots that could become a problem in future.

Answers 1: D, E, J 2: A, H, K 3: A, B, G 4: C, F, I

Plants can be ordered in a variety of ways.

Each root containment matches to THREE statements:

(Note: A is repeated because it's used for two different numbers)

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When new plants arrive on site certain checks need to be made.

List what needs to be checked for under each of the following categories:

Plant label - Binomial name (and cultivar name if applicable) - Plant passport details

The physical plant - Free from pests - Free from pathogens - Does not show signs of nutrient deficiency - Plant is not pot bound

What does moss and liverworts growing on the compost signify? The plant has been overwatered at the nursery, which can result in poor root health. The plant has been in the nursery over winter, allowing moss and liverwort growth to develop.

What signs should be looked for that signify current or past pest damage to a plant?

What signs should be looked for that signify current or past pathogen damage to a plant?

Plant checks and quarantining is part of best practice in horticulture.

Decide which of the following statements are true or false:

Best practice is to check plants for signs of pests or pathogens as soon as they arrive on site from a local nursery.
It's good practice to remove plants from their pots to check the roots.
When trees are received on site they should always have the compost washed off to check their roots aren't circling within the pot.
Bare root woody plants should be quarantined for three weeks and then heeled in if their final planting location is not ready.
An empty, shaded glasshouse near the entrance to a garden is a suitable place to quarantine plants on site.
Ideally plants should be quarantined for at least three weeks.
It's better to source bare root plants than potted ones, even though they're slower to establish.
You find vine weevil larvae in the pot of a quarantined plant. Watering the compost with boiling water is a non-toxic way to eradicate the pest and allow the root system to recover.
Your next door neighbour gives you a rooted cutting of an old shrub from their garden. You spot an aphid on it. It's essential to destroy the cutting rather than allow it into your garden due to the biosecurity threat.
You receive potted plants with lots of roots growing out of the holes in the pot base. This is a positive indicator of plant health.

Answers 1. False. If the nursery is local then plants should be inspected at the nursery to prevent potential entry biosecurity threats. They should be inspected again on arrival. 2. True 3. False. This will cause significant damage during the growing season and on evergreen trees in winter. 4. False. Whilst they should be quarantined, they must be heeled in or temporarily potted with fresh compost within the quarantine area. Otherwise they will desiccate and potentially die. 5. True. 6. True. 7. True (they have a lower biosecurity threat) 8. False. This will kill anything living in the pot, including roots and therefore cause plant death. 9. False. If it's from a long established plant next door it's unlikely to be a source of new pests or pathogens to your garden. The neighbours plant should be inspected to check for signs of ill health and then a decision can be made. The aphid on the cutting can be destroyed if the cutting is kept. 10. False. This is a sign the plant is potbound.

You find a specimen of a rare shrub cultivar in a local nursery. It has clear signs of chlorosis but it's the last plant left and you're keen to purchase it.

What considerations are there in the potential purchase of this plant?

Plants with nutrient deficiency are more susceptible to pest and pathogen attack and need to be thoroughly checked for these.

The root system also needs to be checked - chlorosis could be linked to poor root health.

If the plant is otherwise healthy it could be purchased despite the chlorosis. Once on site and in quarantine it should be given regular liquid feeds (fertigated) at the appropriate strength (as per the fertiliser label) with a complete fertiliser (this contains all the nutrients plants need for healthy growth). A foliar spray with dilute fertiliser can be used in addition to fertilising the root zone.

The plant should be checked regularly. Although some leaves may senescence, those with lesser signs of chlorosis should return to a regular colour and healthy growth should resume. If it doesn't, it's a sign there's a more significant problem.

Plants are commonly grown in containers and sold at nurseries prior to being planted in gardens. What are the most sustainable options for the containers they are grown in?

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Put the following statements in the correct order when planting a new garden bed in autumn. The area has compacted soil:

Plant smaller specimens.
Mulch the bed with organic matter. This can be done in combination with the previous step.
Decompact the soil via single digging, incorporating organic matter.
Plant the largest specimens, which includes some 8ft tall trees.
Place plants at the correct spacings on the soil surface.
Water the area thoroughly to settle soil around plant roots.
Check the plant arrangements against the planting plan and adjust if necessary.
Plant spring flowering bulbs.
Lightly fork the soil to remove surface compaction where it has been trodden on.
Rake the soil level.
Stake the trees.

Answers The correct order of numbers is: 3, 10, 5, 7, 4, 11, 1, 8, 9, 2, 6

What is soil amelioration?

What is modern best practice regarding soil amelioration?

Primary cultivation of soil (a key part of traditional soil amelioration) is no longer recommended as it damages soil structure and harms soil biodiversity.

Primary cultivation is only used where there are issues with compaction and/or drainage, in which case it is only undertaken one time with no further soil disturbance.

Modern practice is to mulch the soil with organic matter and allow soil organisms to improve the soil naturally.

1. When is the best time to plant?

A. Spring

B. Summer

C. Autumn

D. Winter

2. Justify your answer to Q1

3. What are unsuitable conditions for planting?

5. Justify your answer to Q4.

In nature trees germinate from seeds in the soil. As they grow they develop a root flare at soil level. Above the root flare the trunk is adapted to being exposed to air and often dry. The roots below the root flare are adapted to the damp soil conditions. If planted too deep, trees are susceptible to pests and pathogens from wet soil adjacent to their trunks. If planted with the root flare too high they're at rick of instability in high winds.

Trees are not always planted at the correct depth in pots and therefore adjustments may be needed when planting in the ground.

4. At what depth should trees be planted?

A. So the root flare is covered

B. So the root flare is at the soil surface

C. So the root flare is well above the soil surface

D. At the same depth as they are in the pot

Each number relates to a specific word, so if you think (1)________ is 'bananas' then if (1)________ appears later on in the passage, 'bananas' is the missing word.

When planting potted herbaceous perennials they should be planted at the same depth as they were growing in their pots. Bare root herbaceous perennials should be planted with their (1) ________ at the soil surface. After planting, soil should be backfilled and (2) ________ in to ensure good soil-root contact without (3) ________ the soil, which would reduce air spaces and impede optimum root health.

Bulbs should be planted at a depth approximately (4) ________ times their height with the (5) ________ plate downward.

When bare root trees are planted they often need a (6) ________ to prevent them blowing over before their roots have established. It's best to angle the (6) ________ at around (7) ________ degrees with the blunt end pointing (8) ________, into the direction of prevailing winds. A tree tie should attach the tree to the (6) ________ at about a (9) ________ the height of the tree. This ensures the upper part of the tree moves in the wind, which encourages the (10) ________ to strengthen and roots to develop, improving eventual stability of the tree. In unfenced locations where (11) ________ visit the garden, a tree (12) ________ should be fitted around the trunk to protect it from being gnawed. If (13) ________ frequent the garden a much taller barrier will be needed.

When planting potted herbaceous perennials they should be planted at the same depth as they were growing in their pots. Bare root herbaceous perennials should be planted with their (1) crowns at the soil surface. After planting, soil should be backfilled and (2) firmed in to ensure good soil-root contact without (3) compacting the soil, which would reduce air spaces and impede optimum root health.

Bulbs should be planted at a depth approximately (4) three times their height with the (5) root plate downward.

When bare root trees are planted they often need a (6) stake to prevent them blowing over before their roots have established. It's best to angle the (6) stake at around (7) 45 degrees with the blunt end pointing (8) southwest, into the direction of prevailing winds. A tree tie should attach the tree to the (6) stake at about a (9) third the height of the tree. This ensures the upper part of the tree moves in the wind, which encourages the (10) trunk to strengthen and roots to develop, improving eventual stability of the tree. In unfenced locations where (11) rabbits visit the garden, a tree (12) guard should be fitted around the trunk to protect it from being gnawed. If (13) deer frequent the garden a much taller barrier will be needed.

Hint: the missing words in a random order southwest, rabbits, compacting, stake, trunk, deer, firmed, three, guard, crowns, root, 45

Extra Hint: (1) crowns

Extra Hint: (2) firmed

Extra Hint: (3) compacting

Extra Hint: (4) three

Extra Hint: (5) root

Extra Hint: (6) stake

Extra Hint: (7) 45

Extra Hint: (8) southwest

Extra Hint: (9) third

Extra Hint: (10) trunk

Extra Hint: (11) rabbits

Extra Hint: (12) guard

Extra Hint: (13) deer

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Establishment irrigation may be needed in the first growing season.

Decide which of the following statements are true or false:

Irrigation should be automated and come on every evening through the summer.
Saved water from water butts should not be used on a new plantings because they are vulnerable to microbes.
It's more water-wise to use soil-level irrigation such as soaker hoses or drip hoses than sprinklers.
When irrigating it's important to ensure enough water is supplied to soak down into the soil.
Plants that are tolerant of dry summer conditions are planted in a sunny microclimate on sandy soil. They will never need to be irrigated.
Excessive irrigation can lead to soil nutrient loss.
It's best practice to use sprinklers for irrigation on hot afternoons so foliage dries as quickly as possible.
To reduce establishment irrigation needs it's best to plant in autumn.
If the soil surface looks dry then new plantings will need irrigation.
Plants appear to be wilting on a hot summer afternoon. This is not necessarily a sign that they need irrigating.
Soaker hoses, drip lines and sprinklers are effective when attached to water butts, reducing pressure on mains or other sources of water.
There is a lower carbon footprint in using sprinklers than soaker hoses.

Answers 1. False. Whilst automation is fine, it should only be used if it is required. Other than containerised plants, irrigation will never be needed on a daily basis. 2. False. Saved water is fine to use on newly planted areas. 3. True. 4. True - there's a delicate balance between irrigating enough to encourage deeper rooting, and over irrigating which is wasteful. 5. False. Until they are established they may need irrigation in very dry weather. Even plants tolerant of dry summers take time to establish deep roots and become resilient to dry conditions. 6. True. Nutrients like nitrogen can be leached from the soil. 7. False. This is wasteful of water due to evaporative losses. 8. True. 9. False. 10. True. Heat flag can occur in some plants in very hot weather. If a plant is wilting early in the morning then it's either in need of irrigation or there's a root-related problem. 11. False. Water butts do not provide the water pressure needed to effectively operate soaker hoses, drip lines or sprinklers. 12. True. Less product is needed in the manufacture of a sprinkler vs. soaker hoses or drip lines to irrigate the same area, and the transport carbon footprint is lower.

This photo was taken at 3pm on a hot summer afternoon.

What type of irrigation system is this?
In what situations is this type of irrigation system most commonly used?
What are the advantages of this type of irrigation system?
What are the disadvantages of this type of irrigation system?
Evaluate the timing of irrigation in the situation photographed.

1. What type of irrigation system is this?

This is pop-up sprinkler irrigation

2. In what situations is this type of irrigation system most commonly used?

Golf courses, public parks and gardens, large private gardens

3. What are the advantages of this type of irrigation system?

It's automated and doesn't require much labour input, saving gardeners time. One sprinkler can cover a relatively large area. Automation in public gardens means they can come on when no/few people are on site, reducing inconvenience if there's spray drift onto paths or other areas people frequent. They can be timed to come on very early in the morning, reducing evaporative water losses.

4. What are the disadvantages of this type of irrigation system?

Requires installing irrigation lines beneath the soil. This is expensive, difficult to maintain and causes soil disturbance. Pop-up irrigation has a limited height so taller plants can block irrigation, preventing some areas being irrigated. Overhead irrigation is always less water-wise because there will be greater evaporative losses than soil-level irrigation. When automated to come on outside of working hours there's a risk that faulty/broken irrigation points may not be noticed quickly.

5. Evaluate the timing of irrigation in the situation photographed.

3pm on a hot afternoon is not an ideal time to irrigate due to a high level of evaporative losses vs. cooler times of day/night. There is also water on the path (right of photo) which could cause a slip hazard.

At 3pm it's likely staff are present so the system can be checked for efficacy, such as blocked nozzles. The area is shaded, meaning evaporative losses will be less than if in full sun - however this is still an poor time of day to be using a sprinkler.

Newly planted trees usually require establishment irrigation.

Name the item around the tree trunk.
How does this item work?
What are the benefits of using this compared to other irrigation methods?
What are the disadvantages of this irrigation method?

1. Name the item around the tree trunk.

Tree gator

2. How does this item work?

The green bag is filled with water, which slowly seeps into the ground beneath via perforations in the base of the tree gator

3. What are the benefits of using this compared to other irrigation methods?

- Water goes directly to the roots near the trunk, which is useful for previously potted specimens which haven't established far reaching roots yet.

- Water seeps into the ground without evaporative losses.

- The volume of water entering the soil is enough to seep down and encourage deeper rooting.

- The tree gator can be reused.

4. What are the disadvantages of this irrigation method?

- The tree gator needs to be regularly refilled when irrigation is needed, which is time consuming and requires walking on the ground near the tree. This could lead to surface compaction unless a thick mulch is applied.

- Unless obscured by surrounding planting the tree gator detracts from a natural aesthetic.

- The tree gator prevents fresh airflow to the tree trunk and can cause the trunk to remain damp for prolonged periods if it's rainy. This is not ideal for optimum trunk health.

- The tree gator has a carbon footprint of manufacture and transport.

What does 'controlling competition' mean in relation to maintenance of new plantings?

In what situations is hand weeding the only option to remove unwanted plants?

How can weeds be controlled with minimal harm to the environment?

In vegetable gardens hoes are often used to prevent the establishment of weeds. How can hoes most effectively be used to achieve this?

New woody plants may need pruning after purchase. What are the key factors horticulturalists look for when pruning newly acquired woody plants?

Removal of dead or damaged stems
Removal of diseased growth
Removal of crossing branches, including those that are actively rubbing together
Removal of congested growth
Removal of a twin leader shoot to leave one leader (on trees)
Potentially tipping back leggy shoots to encourage branching and a denser growth habit

(Note: ideally only healthy, well-shaped specimens should be purchased but this is not always achievable. Plants that are mail ordered cannot be scrutinised and selected and therefore may need some light formative pruning).

How can new young hedges be maintained in the first 12 months to maximise a dense, bushy growth habit?

How can the cutting back of deciduous herbaceous perennials be undertaken in a way that maximises garden biodiversity?

Deciduous herbaceous perennials should be left standing over winter so overwintering wildlife has shelter. In early spring dead herbaceous growth can be cut down. This should be carefully spread on the ground between the crowns of plants, meaning overwintering wildlife is not removed from the area. The arisings act as a mulch, supplying soil-based detritivores and decomposers with a food source, which supports soil biodiversity.

In the first 12 months after planting and staking, what maintenance might be needed to facilitate maximum health on a garden tree?

The tree should be checked for pests. If natural predators are not sufficiently controlling them, spot treatment may be needed. For example, an aphid outbreak in spring before natural predators are active.
Check for signs of disease. If the tree is experiencing pathogen attack it's essential to ensure it remains sufficiently irrigated and doesn't lack nutrients. This maximises the potential of the tree to resist further infection. The pathogen needs to be identified and potential treatment undertaken if research suggests this is best practice.
Tree ties need to be checked periodically and loosened if necessary. If it was installed carefully this should only need to take place once per year.
Rabbit guards should periodically be taken off and any weeds growing up inside them removed. The guard should be replaced.
If any branches become broken or damaged they should be pruned back with clean, sharp secateurs.