How long does it take for bougainvillea to grow roots in water? How long should they be before I transplant?
I'm not at all sure it will produce roots in water, I think it's very unlikely, though someone else might know different. The usual method is from non flowering, softwood/semi ripe cuttings in summer, or hardwood cuttings in winter, or by layering. This thread https://garden.org/nga/searchqa/answer/9679 gives pretty good instructions in regard to all three of these. Note they don't like root disturbance, so when your cutting starts growing eventually, be careful not to disturb the root system too much when potting on or planting out.
Yes, you can root them in water. I actually have had more success doing it this way rather than in soil for some reason. I make sure I keep the water fresh by changing it other days. I actually have cuttings with lots of leaves growing and one even has a flower. I have about 12 cuttings from 3 different Bougainvillea and they all are showing root growth and have loads of leaves sprouting.
I successfully propagate bougainvilleas in water, but there are some tips:
- Choose cuttings that are almost hard (to avoid rotting in water).
- Put them in a small size paper cup half filled with water; remember that wide opening of cups help evaporating water, so keep the appropriate humidity.
- After 2 days when the water level decreases, add some dilute iron powder solution in the cup so the color changes to almost red but you can see the bottom
- Remember that the small white dots appear on the body of cuttings after 10 to 20 days, these are not roots but good signs of doing well.
- Wait until real roots emerge from the bottom of cuttings, about 2 months or more after preparing the cuttings. Wait another month or more until the roots become between 2 to 3 inches long. You will see that roots go around the bottom of the cup. New growth and fresh leaves are another signs of this final stage.
- Put the rooted cuttings in a well draining clay pot and water thoroughly.
- More important tips:
a) best time for taking the cuttings is during or after flowering.
b) best temperature for this method is about 22°C (72°F).
c) keep checking the water level inside cups and add water and iron solution when needed.
d) to avoid fungus remove any leaves that fall inside the cup from cuttings as soon as possible.
e) keep the cuttings away from direct sunlight, very little filtered sunlight is enough.
f) keep the pots in the same place that you keep cuttings for several days and move them gradually to the full sun, otherwise your cuttings will wilt after potting due to changes in humidity and temperature.
This was my 3-year experience of propagating bougainvilleas. Believe or not, it is 10 times more successful than other methods like putting the cuttings inside potting mixture or even using rooting hormone and I sure hope this will help you.
I am also researching about the best way to grow bougainvillea. If the cuttings are developed in water it's best to add the soil you intend growing them on with, to the water gradually to avoid planting shock. Use the same water the roots have developed in, but add the soil very slowly, over a period of four to six weeks depending on pot size, the slower the better, (apparently). What I am going to try is is put sterilised tiny pots into the pot, or whatever you wil use to contain the water, stand it on another upturned pot, then use the same growing medium that they will stay in, then as you slowly add soil the pots will be slowly filling. To prevent the soil from falling straight through, using the base of the pot as a guide I cut circles of kitchen paper, put two together, and fit them inside the base of the pots I have done this successfully many times (the kitchen paper that is). The roots grow through it no problem. Good Luck. 🤗