Why do cuttings root faster when half their leaves are removed?
The key to successful cuttings is to reduce the amount of transpiration whilst the cuttings have no roots. This is sometimes done by spraying the cuttings with mist or placing a polythene bag over the pot of cuttings. We think the key to your results might therefore be the rate of transpiration of the shoot relative to its size. Roughly speaking, those with half the leaves removed will be losing water by evaporation at half the rate of those with full leaf. The cuttings with all their leaves intact may be placing a greater water stress on the shoot which may not be able to grow roots so easily. I wonder whether these were showing signs of wilting? (They would be if they were plants other than ivy, which is designed to lose water slowly and survive in winter when liquid water is scarce (frozen) in the soil.) The cuttings are probably mobilising their starch reserves for the new growth and not relying on photosynthesis. Hence, those with half leaf are not at a disadvantage compared with
