From our roots to our newest leaf, sunlight is not a luxury; it is our very life force. You call it food, but we create it through a magnificent process called photosynthesis. Within our leaf cells are tiny factories called chloroplasts, which use the energy from photons of light to transform carbon dioxide and water into sugars. These sugars are the fuel for every bit of our growth, from the deep-reaching roots that anchor us to the fragrant white flowers we produce. Without sufficient light, this factory slows down. Our growth becomes weak and spindly as we desperately stretch towards any available light source. Our stems weaken, our leaves may yellow and drop, and our ability to produce flowers diminishes significantly. Therefore, the question of sunlight is a question of our vitality.
For us Star Jasmine vines (*Trachelospermum jasminoides*), the perfect condition is what you would call "Full Sun to Partial Shade." In practical terms, this translates to a minimum of four to six hours of direct, unfiltered sunlight each day. Ideally, this light comes from the morning sun, which is bright but less intense than the harsh afternoon rays. This amount of light provides the perfect energy balance. It fuels robust photosynthesis, leading to strong, sturdy stems and a dense covering of deep green, healthy leaves. Most importantly, it provides the abundant energy reserves required to produce the prolific clusters of intensely fragrant flowers for which we are known. In these conditions, we are not just surviving; we are thriving and able to express our full potential.
We are resilient beings and can adapt to various situations. If our planting location receives only two to four hours of direct sun, or is in what you term "Dappled Shade" (like the light under a high-branched tree), we will still grow. However, our growth habit will change. We will prioritize leaf production over flowering, as creating photosynthetic surfaces becomes more critical than the energetically expensive process of reproduction. You will notice that we become a very competent evergreen ground cover, but our flowering will be sparse. In deep shade, with less than two hours of direct sun, we will struggle profoundly. Our growth will be extremely slow, our internodes (the spaces between leaves) will become long and leggy, and our leaves will be fewer, smaller, and potentially a paler shade of green. Flowering in deep shade is highly unlikely.
While we need ample light, there is an upper limit, especially depending on your local climate. In regions with very hot, intense summer sun, being planted in a location that receives full, blazing afternoon exposure can be stressful. Our leaves can become scorched, developing brown or yellow patches. The soil will dry out much faster, putting additional stress on our root system. In such climates, we greatly appreciate a location where we receive the vital morning sun but are protected from the most intense afternoon heat by a wall, a fence, or the shade of a larger plant. This "partial shade" condition in a hot climate is often preferable to full, all-day sun, as it prevents stress and conserves moisture.
When you bring us indoors, our light requirements become even more critical. A windowsill is our entire world. We need the brightest spot you can provide, ideally a south-facing window where we can bask in several hours of direct sunlight through the glass. An east or west-facing window can also suffice. A north-facing window will rarely provide enough light for us to thrive indoors, often leading to the weak, leggy growth described earlier. You must understand that the light intensity filtering through a window is significantly reduced compared to being outdoors, so placing us in your home's sunniest location is essential for our health.
