From my perspective as a rosemary plant, I am naturally a woody, perennial shrub. In my native Mediterranean habitat, I grow in a loose, sprawling manner, often becoming quite large and woody at the base. My natural instinct is to seek the sun, which can sometimes lead to elongated, "leggy" stems as I stretch towards the light. This legginess is characterized by long sections of bare woody stem with sparse foliage only at the very tips. This is not an ideal form for a garden setting, and it is a sign that I am not receiving the signals I need to produce dense, bushy growth from my lower nodes.
My growth is governed by a principle called apical dominance. The topmost bud on each of my stems (the apical meristem) produces a hormone called auxin that suppresses the growth of the lateral buds further down the stem. This encourages me to grow tall rather than wide. When you prune me, you physically remove this dominant bud. This action disrupts the auxin flow, effectively breaking its hold on the dormant buds below. With the suppressing signal gone, these lateral buds are "released" and stimulated to grow into new branches. Each cut you make doesn't just remove growth; it sends a direct command to my system to produce two or more new stems from the point of the cut, resulting in the fuller, bushier form you desire.
To encourage the most vigorous and healthy regrowth, it is best to prune me during my periods of active growth. For me, this is primarily in the spring, just after I have finished my main flowering period. This timing is perfect because my energy levels are high and the warm weather and long days provide ideal conditions for me to quickly heal the wounds and produce new shoots. You can also give me a lighter pruning in early summer to further shape my growth. It is crucial to avoid major pruning in late fall or winter. During this time, my growth has slowed or halted, and I will struggle to recover from the cuts, leaving me vulnerable to frost damage and disease.
Where you make your cut is of utmost importance. You must always prune me into the green, leafy growth, never back into the old, brown, leafless wood. My older woody parts have far fewer dormant buds, and if you cut into them, I may not be able to generate new growth from that point, leaving a permanent bare spot. Look for a spot on a green stem where you can see small, bumpy nodes or tiny leaves starting to form. Make a clean, angled cut about a quarter-inch above one of these nodes. For a general shaping and to encourage density, you can safely remove up to one-third of the length of the new, soft growth. For a very overgrown plant, this may be done over several seasons to avoid shocking my system.
After you have pruned me, I will direct my energy into healing the cut stems and pushing out new lateral shoots. To support this process effectively, ensure I am receiving plenty of sunlight. This is the primary energy source that fuels this new growth. Water me appropriately, allowing the soil to dry out slightly between waterings, as my roots are susceptible to rot in soggy conditions. While I am not a heavy feeder, a light application of a balanced, organic fertilizer after a spring pruning can provide the slight nutrient boost needed to support my renewed bushy expansion.
