As a gardening and landscaping expert, I can confidently say that rooting powder is not always necessary when it comes to propagating plants from cuttings. There are many plants that can easily root in water without the use of additional rooting hormone. While rooting powder can certainly aid in the rooting process, it is not an absolute requirement for success.
I have personally propagated numerous plants without the use of rooting powder and have had great success. In fact, some plants, such as pothos (Epipremnum aureum) and spider plants (Chlorophytum comosum), are incredibly easy to propagate in water alone. These plants have nodes along their stems, which can be submerged in water and will eventually develop roots. I have seen these cuttings root within a matter of weeks without the need for any rooting hormone.
Another example is the coleus plant (Plectranthus scutellarioides), which can also root easily in water. I have taken cuttings from mature coleus plants, removed the bottom leaves, and placed the stems in a jar of water. Within a few weeks, roots would start to emerge from the nodes, and I could then transfer the rooted cuttings to soil.
It is important to note that not all plants will root successfully in water alone, even with the use of rooting hormone. Some plants, such as woody shrubs and trees, may require more specialized techniques for successful propagation. However, for many common houseplants and herbaceous plants, water propagation can be a simple and effective method.
If you do decide to try rooting cuttings without rooting powder, there are a few things to keep in mind. Firstly, make sure to choose healthy, disease-free cuttings from the parent plant. Remove any leaves that would be submerged in water, as they can rot and potentially harm the cutting. Place the cuttings in a jar or container of water, making sure that only the nodes are submerged. Change the water regularly to prevent stagnation and bacterial growth. Keep the cuttings in a warm, bright location, but avoid direct sunlight, as this can cause excessive heat and evaporation.
While rooting powder can be a helpful tool in propagating plants from cuttings, it is not always necessary. Many plants can root easily in water alone, without the need for additional rooting hormone. By choosing the right plant species, providing proper care, and being patient, you can successfully propagate plants without relying on rooting powder.
