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Roses

The foliage on some of my roses is covered with pale, bleached spots, and underneath the leaves, there are small creamy white insects that leap off when disturbed, what can I do please?

The pests you describe is the leaf hopper at the nymph stage of their cycle.

Control it by spraying under the leaves with a suitable insecticide.

 

Some of my roses suffers badly from mildew, what would you advise is the best way to control this?

Prune the bush quite severely in spring and then spray with a suitable fungicide.

Once new shoots have grown out a few inches, repeat the fungicide application.

Apply a rose feed, water well if the soil is dry and then mulch with compost or bark.

Keep the soil well watered in dry weather and spray with fungicide every three to four weeks to keep the new growth free from infection.

After a year of such treatment there should be a lot less mildew and the spraying could possibly be reduced in following years.

 

When do I prune a climbing rose?

Prune in the autumn.

Shorten all the side shoots on the main stems to within a few inches of their base.

Do not tie in the growths upright but arch them over and tie them into place.

This will encourage side shoots to appear along their whole length in the spring.

 

When is the correct time to prune a rambling rose?

Early September.

Cut out some of the older stems to ground level, retain all the new young growth made this season and tie them into the support system.

 

l sprayed all my roses in spring with systemic fungicide against black spot, to no avail it seems, as they still have it, can you suggest any other treatment?

None! other than simply repeat the spring treatments.

Two or three sprays of the same fungicide applied at two week intervals, should clear it up.

 

In early July, the leaves of nearly all my large-flowered roses were eaten away by yellowish green shiny grubs, can you tell me what they are, and how to stop them attacking again please?

The grubs will have been the larvae of the rose sawfly.

Adults emerge from the soil in May and lay their eggs on the foliage.

The grubs feed through June and just into July, before dropping to the ground to get ready for winter.

During the winter, cultivate gently around the bushes to expose or disturb the overwintering grubs in their silken cocoons.

Next year in late May/early June, keep a look out for the very first sign of damage, and spray with a fatty acids insecticide.

 

Some of our roses suffer if wet weather coincides with flowering, the flowers simply fail to open, turn brown then rot, is there anything we could do to help prevent it?

This is something that affects a number of older, fully-petalled varieties.

Short of giving some temporary protection over the bush during the flowering period, there is no effective treatment.

 

On some of my species roses I have found a scaly growth towards the base of the stems, can you tell me what this is and how to control it?

The insect causing the problem is the rose scale, also known as scurfy scale.

Eggs are laid under the old scales in the summer and the new generation of nymphs settles in new feeding sites by autumn.

Mating occurs in spring, thereby starting off the next generation.

Control by pruning out infested shoots where possible and / or by spraying with a systemic insecticide.

 

Is it better to buy bare root bushes or container-grown plants?

A matter of personal choice really!

Bare root bush roses are plants that are lifted in the nursery in the autumn and sold with no soil on their roots, if planted with care, they will flower the following summer.

They are normally available between November and March, and are generally cheaper than containerised plants.

Container grown roses are available for most of the year and can be planted out on day of purchase providing the ground conditions are OK.

 

When should I prune a newly planted climbing rose ?

lt should not be necessary to prune a newly planted climbing rose.

Train the main stems up/along supports, and tie them in.

Cut out any dead, diseased or weak growth.

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