What is a tree?
A perennial plant with a single woody self-supporting stem or trunk usually unbranched for some distance above the ground.
What is a shrub?
A woody perennial, usually smaller than a tree, which is divided into separate stems at or near the ground.
What are some of the uses of trees in a garden?
- Structural planting
- Shade
- Shelter
- Privacy
- Decoration
- Area division
- Wildlife habitat
- Fruit production.
Explain some considerations when choosing a tree or shrub for a site.
- Aspect and soil. Sun, prevailing winds, drains and other services, soil fertility and pH.
- Type of garden. Choice should suit garden style/local environment
- Available space. Size tree/shrub gets to, distance from house etc
- Aesthetics. Shape, leaf colour, flower, fruiting time, etc.
What’s the difference between a standard and half-standard tree?
Standard: single clear stem 1.5m - 1.8m in length. Tree should be around 3m in height.
Half-standard: 1.2m - 1.5m of clear stem. Tree should be around 2m in height.
When are the best times of year to plant a tree?
Autumn or spring. (Container grown stock may be planted almost all year around.)
Explain the planting of a tree, including site preparation.
- Remove all weeds, esp. perennial weeds like Aegopodium podagraria.
- If planting in a lawn, cut a circle and skim off turf
- Excavate the hole.
- Hole should be square and large enough to accomodate the rootball + 5cm all round.
- Depth should ensure the flare of the trunk will be at soil level.
- Base of the hole should be flat and the sides vertical.
- Don’t turnover the soil in the base of the hole.
- Don’t add organic matter or fertiliser to the base of the hole.
- Drive in the stake according to the method appropriate to the tree (do this before planting to avoid damaging rootball).
- Should be 45 degree angle on windward side.
- Stake should be 1/3rd the height of the tree.
- Position the tree (ensuring level is correct. Look for nursery mark if bareroot). Check for best angle from vantage points.
- Backfill. Take care to eliminate air pockets, firm with boot. Finish neatly.
- Water tree in well.
- Mulch. 7.5cm layer to retain moisture. Not up to crown.
What after care does your tree need in spring?
- Refresh the mulch (water it first) to prevent weeds and to retain moisture
- Formative pruning to develop shape of tree. Remove any water shoots from main stem, any double leaders, crossing branches, DDD.
What after care does your tree need in summer?
- Ensure tree is well watered in first 2/3 years. 15-20 litres every fortnight during growing season if sufficient rain has not fallen.
- Keep weed free around base as weeds compete for nutrients and may harbour pests and diseases. Fork or hoe, but be careful not to damage tree roots.
- Check for pests and diseases and treat.
What after care does your tree need in autumn and winter?
- Check the stake and loosen the tie if necessary
- Remove heavy snow falls from branches, esp from conifers so shape isn’t damaged.
List three ameliorants that can be added to the soil when planting a barerooted tree.
- Leaf mould
- Grit to improve drainage
- Mycorrizhal fungi
- Fertiliser (e.g. Growmore base dressing).
Describe three methods for staking trees.
- A short stake at 45 degrees up to 1m up the trunk, angled towards the wind, secured with a buckle tie
- Double stakes at 1m or up to 2m from the crown and 30cm-45cm between the stakes, using cross ties or a cross beam to secure the tree to the stakes
- A single upright stake at 1m to 2m in height, secured by a buckle tie.
Name some common diseases that affect trees.
- Honey fungus
- Fireblight
- Bacterial canker
- Dutch elm disease.
What kind of pruning should you do for all trees?
Remove dead, diseases and damaged tissue.
Describe how to prune three distinct named shrubs for different seasons of interest.
GROUP 1: Forsythia x intermedia: Grown for spring flowers. Pruned in April/May, directly after flowering by removing some branches back to the base and reducing the length of some branches to retain shape
GROUP 2: Buddelja davidii: Grown for summer flowers. Prune in February/March, by cutting all stems back to 5cm of the old wood (staghorn shape)
GROUP 4: Cornus alba: Grown for winter stem interest. Pruned in March/April by stooling (cutting all stems back to 5cm from their point of origin).
Name one shrub for each of the following:
- Spring flowering
- Summer flowering
- Autumn display
- Winter interest
Spring flowering: Camellia japonica, Forsythia x intermedia ‘Lynwood’
Summer flowering: Buddelja davidii, Lavandula angustifolia
Autumn display: Euonymous alatus, Cornus alba
Winter interest: Rhus typhina, Stachyurus praecox.
State how powdery mildew can be minimised on woody plants.
- Removal and destruction (by burning) of infected, fallen leaves
- Pruning out and destroying infected plant material
- Mulching to reduce water stress and make plants less susceptible
- Water plants at soil level
- Prune plants to improve air flow.
Describe the symptoms and control of honey fungus.
- Fungal diseases
- Wilting foliage in spring, yellowing
- Bootlace or black straps of fungal rhizomorphs present under bark and in the soil at base of tree
- In autumn light brown toadstools may be present
- Plant less susceptible species
- Remove and destroy infected plants, especially roots and stump. Dig around tree to 70cm depth to impede progress of rhizomorphs.
Describe the symptoms and control of Apple and Pear Canker.
- Fungal infection
- Cankers present (areas of dead sunken bark on fruiting spurs and branches) Old cankers have dead wood at centre. Branches eventually die.
- Plant less susceptible cultivars
- Cut out infected branches
- Use chemical fungicide (after picking fruit but before leaf fall, then again after leaf fall).
Describe the symptoms and control of Coral Spot.
- Fungal infection
- Dieback of branches. Small coral-pink pustules appear on the bark of infected stems throughout the year, esp winter
- Avoid pruning in wet weather
- Cut infected stems back to healthy wood and burn infected wood.
