Actually, the rosemary is a very easy-care plant - if it weren't so unpredictable. Wrong location, too little water or too much, winter too cold or too warm; the sensitive shrub is difficult to please. Many rosemaries turn brown after a while, mostly from the tips of the needles. But the twigs can also dry up quickly, especially towards the end of winter.
Too much moisture is usually to blame
If the needles turn brown and fall off, there are two possible reasons: either the rosemary is too wet or too dry. Before you start treating the plant, you should find out the real cause. In most cases, however, too much water will damage your rosemary, true to the old gardener's adage "More plants have been watered to death than they have dried up". Too high humidity, too much irrigation water and especially waterlogging lead to the rosemary roots rotting and finally being unable to supply the above-ground parts of the plant. In this case, the only thing that helps is digging up or repotting the rosemary and replanting it in a new spot or pot in fresh substrate - after the rotting roots have been pruned, of course.
Brown needles from pest infestation
However, brown needles can also have another cause, namely an infestation with pests such as spider mites, scale insects or tripe. Fungal diseases are also quite common. The gardener usually notices an infestation of pests or fungi towards the end of winter, especially if the plant has overwintered indoors. The cause is often too warm hibernation and, as a result, too low humidity. Many pests love dry heating air and attack dry plants, which are also weakened by overwintering and are therefore more susceptible. Examine your rosemary carefully and look out for small animals, especially on the underside of the leaves - these are often only a few millimeters long and not always visible to the naked eye.
tips and tricks
First try to combat the pests or fungi with biological agents. Chemical pesticides (e.g. fungicides) must never be used on a plant intended for consumption! Greater humidity often helps against unwanted animals, mildew and other fungi can be treated with a garlic broth.
IJA