Wash the rose hips and, if possible, cut both ends tightly so that the stem does not change the taste.
Bring the water to a boil and cook the rose hips for 5 minutes while stirring. Pass the resulting liquid through a sieve and crush the remains of the rose hips in the sieve. Then again through a filter, e.g., coffee filter, give.
Bring to the boil again and cook with the preserving sugar for 5 minutes. Add the lemon juice.