Plums

Question 1

Name and explain two common plum rootstocks.

Answer 1

• Pixy: dwarfing rootstock, trees reach 2m
• St Julian A: semi-dwarfing, trees reach 4m.

Question 2

Explain the pollination of plums.

Answer 2

Some plums are self-fertile and do not require cross-pollination.

Others are self-sterile and require cross pollination from another cultivar in the same or adjacent group.

Question 3

Explain site and soil selection for plums.

Answer 3

• Need protection from frost (flower early)
• Sunny, sheltered site to promote ripening (dessert cultivars require more sun)
• Deep fertile loam
• Free-draining yet moisture retentive (not chalky soil).

Question 4

Explain staking of plums by rootstock.

Answer 4

• Pixy requires permanent staking
• St Julien A requires staking for first 2-3 years.

Question 5

Explain formative pruning of plums.

Answer 5

• Should not be carried out in winter (increases disease risk)
• Carried out in spring (and routine pruning is carried out in summer)
• Plant a feathered maiden
• The first spring select three or four evenly spaced laterals (highest 90cm above ground) trim by 2/3rds; remove the leader
• The second spring select three or four of the strongest sub-laterals and prune back by half; remove all other sub-laterals.

Question 6

Explain the cultivation of plums.

Answer 6

• Protect from frost
• Check stake and loosen when necessary
• Keep base weed-free
• Mulch regularly
• Irrigate in dry weather (20l/sqm. Important after fruit set)
• Thin the fruit to 8cm apart
• Protect againNext st birds
• Routine pruning in summer, removing excessively vigorous and awkward growth.

Question 7

When do you harvent various types of plums?

Answer 7

• Earlies - early August
• Mids - late August to early September
• Lates - October to early November.

Question 8

Name a pest and a disease of plums, including symptoms and control method.

Answer 8

Winter moth

• Green caterpillar with yellow stripes, chews holes in leaves and bud in Spring through early Summer. Extensive damage to blossom
• Grease bands around trunks in mid-autumn, spray bacterial agent, use an approved insecticide as leaves emerge.

Silver leaf

• Silvery fungus creates sheen on leaf, branches become dark brown, branches die back
• Do not prune in winter, remove infected limbs 15cm below infection.

Question 9

Name three dessert plums.

Answer 9

• Early Laxton AGM
• Victoria AGM
• Late Transparent.

Question 10

Name three culinary plums.

Answer 10

• Early Rivers
• Purple Pershore
• Marjorie’s Seedling AGM.