Rose disease

Question: treatment for excess manganese

my girlfriend's roses have stains that are attributable to the excessive presence of manganese in the soil and I would like to know how to cure them, thank you !!!

Rose disease: Answer: excesses of manganese

Dear Danilo,
many pathologies manifested by plants, especially if they are grown in pots, can be traced back to problems linked to deficiencies or excesses of particular chemical elements in the soil; as it happens for human beings, which show particular symptoms, related for example to the lack or excess of some fundamental vitamins, the same is true for plants. And just like human beings, who add to their diet foods tablets that contain just the vitamin they lack, or remove other foods from the diet, the care for the plants is the same, considering also that some minerals they are necessary for the functioning of living beings, but in very small quantities. Therefore, also for plants there are fertilizers that contain microelements, such as manganese, iron, boron, and fertilizers that do not contain them; in general, it would be advisable to always provide the plants with a good fertilizer, especially if they are cultivated in pots, since over the months the earth of the pot does not receive from the outside decomposing material that enriches it, and therefore its composition derives from what we supply to plants or not. A good fertilizer should always contain microelements, along with the typical macro elements, namely nitrogen, phosphorus and potassium; if you check the label of the product you normally use, and notice that it does not contain any micro-elements, change the fertilizer. I remind you that fertilizers are important especially when the plants are in full vegetative growth, and are not necessary during the winter months; if you think your roses have received too much Magnanese, try repotting them with new soil: when our plants are in pots, it is also a good rule to repot them periodically, at least every two or three years, in order to provide them with a new and fresh substrate , rich in every micro-element that can be useful for their development. Having said this, it is not easy to diagnose a deficiency or an excess of microelements, and it is not said that the only pathology that afflicts the plant is this; typically, leaf yellowing can also be a symptom of iron deficiency, or an excess of watering that favors the development of bacteria. Dark spots, on the other hand, can be a symptom of scab or rust. So it is necessary to repot the plant, or to explant and replace the earth with new soil without touching the root bread too much, and at least to treat it with a systemic fungicide, to prevent the presence of fungal diseases.