From my point of view as a rosemary plant, being "leggy" is a direct response to my environment. It is not a disease but a survival strategy known as etiolation. When I do not receive sufficient light energy, my internal systems prioritize growth in search of it. I stretch my stems rapidly, elongating the spaces between my leaf nodes. This rapid vertical growth comes at a cost: my stems become thin and weak, and I produce fewer leaves because I lack the energy to create dense, bushy foliage. My primary goal is to reach a light source, and I sacrifice structural integrity and culinary value to achieve it.
The single most critical action to restore my full growth is to correct the light deficit. As a Mediterranean native, I am adapted to long hours of intense, direct sunlight. Ideally, I require a minimum of six to eight hours of direct sun daily. If I am grown indoors, a south-facing windowsill is my best option. However, during winter or in naturally dim homes, even this may not be enough. In such cases, you must supplement with a full-spectrum grow light placed just a few inches above my foliage for 12-14 hours a day. With adequate photons, my photosynthetic processes can ramp up, allowing me to produce abundant energy. This energy will then be directed into strengthening my existing stems and producing new, compact growth from the nodes, rather than futilely stretching.
While light is the solution, pruning is the tool that guides my recovery. Simply giving me more light will not magically fill out the long, bare stems. You must encourage me to branch out. Pruning signals a hormonal response within me. The dominant growing tip at the end of each stem produces a hormone called auxin that suppresses growth from the lateral buds lower down the stem. By cutting back this tip, you remove that source of auxin. This signals the dormant buds in the leaf axils lower on the stem to wake up and produce new branches. Always use sharp, clean shears and make your cuts just above a set of healthy leaves, where you see small, visible buds. This forces me to become bushier from the base upwards.
My recovery from a leggy state requires energy, and that energy must be supported by proper root health and nutrition. First, ensure I am not sitting in waterlogged soil. My roots need to breathe, and soggy conditions will lead to root rot, further stunting my growth and potentially killing me. Plant me in a very well-draining, gritty soil mix. Second, be cautious with fertilizer. A leggy plant is a stressed plant. A heavy dose of high-nitrogen fertilizer might encourage a burst of weak, soft growth that exacerbates the problem. Instead, after a corrective pruning, a very diluted, balanced fertilizer can provide a gentle boost to support the new, compact growth you are trying to encourage. The focus should be on building strong roots and stems, not forcing rapid, succulent leaf production.
In some instances, I may have become so excessively leggy that the main stems are woody and bare, with no green leaves left on the lower sections. In this case, the old wood has a very low chance of producing new buds. The most effective restoration may be to take the healthy, green tips from my upper growth and propagate new plants. Take 3-4 inch cuttings, remove the lower leaves, and place them in a well-draining potting mix. This gives me, in a new form, a fresh start. You can then care for the new plant with the correct light and pruning practices from the beginning, ensuring a full, compact, and healthy life.
