Are the four plants in your flower bed all in a row? Or are the two (and two replacements) that didn’t do well in a separate section of the bed? They are all the same variety of rosemary? Some possibilities might include—health of the individual plants before they were planted in the ground. If the ones that did not do well were stressed in some way before they were planted, then they would have less of a chance of establishing. However, it might be that something in those spots that is affecting those 2 plants—check the soil for pests (are there any pests nibbling at the roots of those two, such as if there is an insect nest there?), check the light and moisture. In those spots, are the plants getting less or more light or water than the healthy plants? Is there an animal that is bothering the plants in that spot? Any sign of digging? If there is a disease in the soil, then it would likely first affect the two plants planted in the same spot, but may spread to the others if they are nearby. Hope this helps!
Are the four plants in your flower bed all in a row? Or are the two (and two replacements) that didn’t do well in a separate section of the bed? They are all the same variety of rosemary? Some possibilities might include—health of the individual plants before they were planted in the ground. If the ones that did not do well were stressed in some way before they were planted, then they would have less of a chance of establishing. However, it might be that something in those spots that is affecting those 2 plants—check the soil for pests (are there any pests nibbling at the roots of those two, such as if there is an insect nest there?), check the light and moisture. In those spots, are the plants getting less or more light or water than the healthy plants? Is there an animal that is bothering the plants in that spot? Any sign of digging? If there is a disease in the soil, then it would likely first affect the two plants planted in the same spot, but may spread to the others if they are nearby. Hope this helps!