Yes, lovage can stand beside the roses, but it should not be planted inside the rose beast’s elbow room. Think of lovage as a tall, useful garden sentry, not a scrappy ground-fighter. 🌿🛡️

Sun: Lovage does best with full sun to partial shade. Best production is usually with 6+ hours of sun, but it tolerates part shade better than many herbs. In your back-fence spot, it should be fine if it gets a decent chunk of direct light. (The Old Farmer's Almanac)

Size: Give it space. Lovage can get big, often around 1.5 to 2 m tall, sometimes taller, and roughly 60 to 90 cm wide. West Coast Seeds describes it as a massive perennial herb that can reach 1.8 to 2.5 m in a season. (West Coast Seeds)

Soil/water: It likes rich, well-drained soil with steady moisture. Not swamp. Not desert. More “civilized damp cellar with ambition.” RHS notes it may need extra watering in hot weather, especially in full sun or free-draining soil. (RHS)

Beside aggressive roses: Plant it at least 60 to 90 cm away from the rose canes, more if the roses are actively colonizing the republic. Lovage has height, but roses have thorns, shade, and root competition. If the roses flop over it or grab its light, the lovage may survive but sulk.

Concensus: yes, let's try it along the back fence, but give it its own cleared circle and mulch it. Use it as a vertical green guard tower behind or beside the roses, not as a trench soldier directly under them.

Also: lovage dies back in winter and returns from the root in spring. So in winter, the roses will look like they won. This is propaganda. The lovage will be back.