Hello Yates, I’ve just bought 4 Hibiscus cottonwood plants in 200mm pots that are about 6 feet high (see attached photo). When we plant the Hibiscus, because they are not bushy in this early stage, can you offer any advice as to what we can/might do so they do thicken up as time passes – eg cut the height if so how much and when? Also, is it best to wait until the rain that we are experiencing the next few days has passed before we plant them.
Hello Frank, we love Cottonwoods (Hibiscus tiliaceus!). Unless you're in northern parts of Australia where the temps are still warm into the evenings, you may like to overwinter them in pots, so that they can stay in a protected spot. If you're in a cooler climate, planting into cold soil might reduce their ability to get going on the other side of winter. For pruning, always waiting until either after the last frost of your area (frost can burn off the new growth) or until after they flower (mid-late summer, usually) is ideal. In regards to how much to take off, these particular specimens are very long and leggy, we would say take off half to a third - hard prunes are generally done in late August to September, once it's really warm again. It will feel difficult, but if you're going for bushy and not height, then a bigger prune early in the trees life ('formative pruning') will help you in the long run.
Answered: 2 Jun, 2022