Roses

Question 1

What are the three varieties of bush roses?

Answer 1

Large flowered bush (used to be hybrid tea): upright growth, large flowers carried on one stem or in small clusters, repeat flowering.

Cluster flowered (used to be floribunda): Upright growth, bear smaller flowers carried on large clusters or trusses, repeat flowering and often flower for longer periods.

Dwarf cluster (used to be patio): Similar growth pattern to cluster flowered but on a smaller scale.

Question 2

What are the five varieties of shrub roses?

Answer 2

Species rose: Wild roses that have been cultivated

Old roses: A group of roses including Gallica, Moss, Damask and Rugosa from which modern shrub roses have been developed.

Modern shrub: General heading for roses that don’t fall into other categories, for example English roses.

Groundcover roses: Roses with a low spreading habit. Can be vigorous.

Climbers and ramblers: Climbers have stiff upright growth with large flowers, can be repeat flowering. Ramblers are more flexible with smaller flowers carried in clusters, once a season.

Question 3

List and explain some uses for roses in garden design.

Answer 3

Traditional rose gardens: Large gardens often had a separate rose garden, often surrounded by a low growing hedge (perhaps of lavender).

Mixed border: Roses mixed in with other plants, for example annuals and herbaceous perennials.

Clothing walls, pergolas, other structures: Climbers and ramblers can create vertical interest or conceal unattractive sights.

Hedging: Rosa rugosa and other shrub roses can be planted to create an informal hedge.

In containers: Dwarf varieties can be grown in pots on a patio.

Question 4

What are the two ways to buy roses and when?

Answer 4

Barerooted in autumn and winter or containerised at any time.

Question 5

Describe the siting/planting of roses in a garden.

Answer 5

• An open, sunny site with some shelter from the wind
• Soil ideally well-drained clay loam of pH 6.5, but tolerant of a range of conditions
• With the graft union 2.5cm below the soil level to prevent suckering
• 40cm from the wall if planted at the base of a wall.

Question 6

Explain the formative pruning of a rose bush.

Answer 6

Prune back hard to an outward facing bud 10-15cm from the base after planting in autumn.

Prune climbing roses to encourage up to six strong canes trained towards the wall.

Question 7

Explain the maintenance of roses.

Answer 7

Feeding: an annual application of a fertiliser which should have a balance of NPK plus trace elements. Applied in spring as a granular top dressing at rate recommended on label.

Dead heading: remove spent flowers to encourage more flowering (expect species that produce hips, if you want hips).

Removing suckers: remove any shoots emerging from the rootstock to stop it depleting the grafted part of the plant.

Pruning: Prune in early spring to remove dead, diseases or damaged wood and to open up the frame of the plant. Prune back by a quarter in autumn to prevent wind rock.

Question 8

Explain the pruning of bush roses.

Answer 8

• Remove any dead, diseased or damaged wood
• Remove any inward or crossing branches to create a nice open vase shape and improve ventilation and prevent disease
• Remove older canes, leaving 6 to 8 healthy young canes
• Prune canes back to approximately 30cm above ground level, just above an outward-facing bud.

Question 9

Explain the pruning of a climbing rose.

Answer 9

• Modern climbing roses flower on this season’s wood
• Prune in spring (although older varieties prune in autumn)
• Establish a permanent framework of canes, trained along a wall or fence as horizontal as possible to break apical dominance
• Once the framework is established, cut the laterals back to 3 buds from the main cane and remove 1 or 2 of the older canes from the ground level in spring.

Question 10

Explain the pruning of a shrub rose.

Answer 10

• Shrub roses can flower both on last season’s wood and this season’s, depending on their group
• In autumn the lateral shoots should be shortened by roughly half and some canes should be removed to ground level to encourage new vigorous growth
• It is important to retain the height of the rose as excessive pruning will result in a plant that is all leaf and no flower.

Question 11

Name three large flowered roses.

Answer 11

• Rosa ‘Peace’ Yellow and pink repeat flowering
• Rosa ‘Silver Anniversary’ White repeat flowering
• Rosa ‘Ruby Wedding’ Pale crimson repeat flowering.

Question 12

Name three cluster flowered roses.

Answer 12

• Rosa ‘Iceberg’ White flowers
• Rosa ‘Gold Bunny’ Yellow flowers
• Rosa ‘Queen Elizabeth’ Pink flowers
• Rosa ‘Mountbatten’ Yellow flowers.

Question 13

Name four pests and two diseases affecting roses.

Answer 13

• Black spot: fungal black spots appear on stems. Soil borne. Use sulphur based fungicide.
• Powdery mildew. White ashy powder fungal growth on leaves and leaf petioles and flower buds
• Rust: orange or black pustules on leaves or stems. Fungal.
• Aphids. Sucking insects in green or black appear on buds and other soft tissue, weakening plant.