SO, I was able to get the pictured flower off the parent plant and wondering if this stem is good enough for planting.
If you want to plant gardenia cuttings there are two schools of thought. Both require the same preparation:
- Use soft wood, that means the green top part of the twig, about 3-4 in / 10 cm long.
- Cut off any flowers and flower buds. Your cutting would waste energy and water on them.
Remove all but the top two pairs of leaves, possibly leave only one pair. The idea is to reduce the amount of leaf surface to minimize water loss (no roots yet to sustain them!) while allowing some photosynthesis for nutrition.
Here the two approaches that are the most common:
- Put a small stem into a vase with water, keep it in a light place but away from direct sunlight, wait for roots to form on the stem, plant once there is a sufficient amount of roots. Do not put any fertilizer or other stuff in the water.
- Prepare a pot with light soil, use your finger or a stick to poke a hole in the middle for the stem. Dip the end (freshly cut!) of the stem in rooting hormone, put it in the hole and close it. Water gently. Cover the entire pot and twig with a clear dome, either something like a cut plastic bottle or tent with foil, but make sure that the cover doesn't touch the plant or you risk fungal infection from condensation. You want to keep humidity high, but not actually wet. Keep in a dark place for a few days, then in increasingly lighter places but always away from direct sunlight. Roots should form within four to six weeks, recognizable by new growth, upright old leaves and a firm stem.
Note that neither method is fail-safe. If your cutting would have had new growth (light green, smaller leaves on top), chances of rooting would be better. Also remember that Gardenias are notoriously difficult to grow, as some other posters here have pointed out to you before.
This instruction is for Gardenias, as you pictured a Gardenia in your question. This does not mean that it will work for every soft wood twig that you cut off somewhere. You need to know for your specific plant what kind of propagation method is appropriate. There are variations in the method or you should take an entirely different approach for other plants. Just a few random examples:
- Fuchsias like "warm feet" if cuttings are planted, and are exceptionally willing to grow roots in a jar of water.
- Pelargoniums (sometimes wrongly referred to as "Geraniums) just rot in a vase but are happy to root in soil even without the rooting hormone and without a cover, as my Dad proves by the dozen every fall.
- Elderberry will simply rot if you take the soft green tips. Here you take woody pieces with two sets of nodes, 1/2 in. thick, cut in late spring or early summer. One node goes into the soil, the other will grow leaves. They can be rooted in water, but the vase must be opaque and the risk of failure/rot is high.
While there are some common tips (reduce foliage to minimize water loss, remove flowers, keep shaded for a few days), there is no "one fits all" method of propagating plants! There won't be another answer, no matter how often you ask for it.