Rose Rust & Aphids
Gavin
Posts: 27
Last year several of my most vigorous roses succumbed to rose rust. Some had been defoliated three times during the year in an attempt to control the infection without chemicals damaging to beneficial insect.
It was a bad year for the roses. I had fed them with a combination of potash and fish, blood and bone meal.
This year as early as January my roses had been affected by greenfly. I didn't treat them immediately because I wanted to take measures against rust.
To step back in time for a moment, he garden that I inherited has awful soil, about the top eight inches are just about ok, beneath that it is heavy clay, so I began 4 years ago adding lime and manure to the soil to lighten it. I then read that the absence of acid in the soil since the Clean Air Act has led to a upsurge in fungal infection of roses. I wondered if the lime had contributed to this problem. To add acidity to the soil I began by puffing yellow sulphur around the roses and directly on to them. I then added sulphur soil. Later I began using wettable sulphur in the highest concentration given on the packet all over the roses - this seems to have improved the condition of some roses, but has not prevented the rust from appearing on others.
As far as tackling aphids is concerned I've been using a concoction of agricultural soap mixed with Ecover detergent but I've added a few drops of essential oils with fungicidal properties in an attempt to prevent rust taking hold when in the higher humidity caused by aphid spraying. It took two goes with this to do damage to the infestation but there are still stubborn hangers on.
I have planted a great deal of garlic around some roses which does seem to make them less prone to insect invasion. I've introduced ladybird larvae and lady birds - which always clear off over night ( though this year I have actually found British ladybirds for the first time!!).
I know I can have beautiful pest free roses by using chemicals that will kill off every insect in the garden. I made that mistake once some years ago for Lupin Aphid and was totally gutted by the result.
I haven't used a fungicide because don't know what effect it will have on the beneficials.
I'm certain I can learn from your collective experience and look forward to receiving your pearls of wisdom.
Gavin
Posts
Hi Gavin - I think you are over complicating your soil conditions, roses aren't over fussy with PH but for extremes, best to work with the soil you've got than trying to change it. The clay soil is no problem for roses either if anything they love it, roses are very greedy plants and clay locks up nutrients.
I spray aphids with fairy liquid does the after job after one or two applications. Or I squash them if there a lot.
Other than remove fallen leaves in autumn and prune out very affected stems I dont know what else you can do organically with the rust problem. The high potash feed should help but it might be something your going to have to persevere with.
Hi Perki,
thank you for your reply. I agree with you about working with what I have. Once upon a time I had visions of an ideal garden with things that couldn't possibly grow together. Now I spend a lot of time looking in other gardens locally for plants and I like and looking to see if they are growing healthily.
The dictum of the "right plant for the right place" has borne fruit. So my efforts with sulphur have been more about controlling fungus (which I'm led to believe dislike acidic soil) than trying to create a particular PH that would only be temporary anyway.
I've just been round the garden and looked at the roses that suffer the fungus the most. Interestingly they are all from the same well known commercial rose breeder/supplier - they are also the ones which have aphid infestation. The others have been grown much more locally. Now I don't know if that makes a difference but it's interesting.
Trial and Error!