Blackspot is one of the diseases that is incredibly difficult to get rid of. Year after year, you think you have it whipped, and back it comes. But we have a natural organic solution that works as well as (if not better than) those traditional toxic remedies.
This starts, as the name would suggest ,with black spots on the leaves. As the spots get bigger, they develop a yellow halo around them, the leaf begins to wither, and eventually falls off. A bad infestation can see a plant totally stripped of foliage. The culprit is a fungus, Diplocarpon Rosae, and the spores from this can remain in the ground and reinfect the bush year after year.
The first step towards cutting down on the blackspot infestation, is to ensure that infected leaves are removed from the plant. Also, as it can remain dormant in the ground, pick up any dropped leaves and burn them (do not compost them!). The overall plant health plays a role as well, and a regular application of sulphate of potash will help control blackspot.
Remember that blackspot thrives in humid and/or damp conditions, so keep your roses well thnned out in the center to aid air circulation, and try to avoid watering the foliage. Instead, water around the base of the plant.
There are plenty of anti fungal sprays available for blackpot, just ask in your local garden center. However, natural and organic treamtments can work just as well, if not better than those toxic fungicides.
Mix 1 part milk to 2 parts water and spray the bush, gettingboth sides of the leaves. Do this weekly. It really does work!
Bicarbonate of Soda:
2 teaspoons per 5 liters of water, mix in a little dishwashing liquid to help it stick to the foliage. As with the milk solution, spray weekly during the peak blackspot season.
Sometimes, no matter what you do, nothing seems to work. There will often be a bush or two in your garden that comes out with bad blackspot year after year. Unless you have sentimental reasons for keeping it, then just replacing it with a more disease resistant variety makes sense. But for the majority of your garden, vigilance with picking off infected leaves, picking up the fallen ones and regular applications of either milk or bicarb of soda should make a big difference.
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