IBA rooting hormone is simply a helper, not a requirement.
It is a lab-made version of a hormone plants already produce on their own to start new roots. When you apply it to a fresh cutting, you are giving the plant a small signal that says, “make roots here.”
For many common houseplants, that signal is already strong enough without any product. Soft, green stems like pothos, philodendron, tradescantia, and similar plants usually root because conditions are right, not because a hormone was added. Warmth, oxygen around the stem, gentle moisture, and adequate light matter far more than anything in a bottle.
Rooting hormone tends to be more useful with woody or slow-rooting plants. Shrubs, trees, and tougher cuttings sometimes benefit because their natural hormone levels are lower or slower to concentrate at the cut. This is why commercial growers often use IBA, not because plants cannot root without it, but because it improves consistency at scale.
There are a few common misconceptions. Rooting hormone does not prevent rot, and using more does not mean faster or better roots. In water propagation especially, the main limitation is low oxygen, not missing hormones, so IBA rarely changes the outcome.
In practical terms, if your cuttings are kept warm, lightly moist, and in a well-aerated medium with reasonable light, they will usually root just fine on their own. IBA can help in harder cases, but it cannot compensate for poor conditions.
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