When it comes to cutting back mahonia plants, you have some flexibility in how far you can prune them. These evergreen shrubs can tolerate quite a severe pruning, so you have the option to cut them back quite significantly if needed.
In general, it’s recommended to cut back mahonia plants to about 15cm (6in) from the ground. This is usually done in late winter to early spring, before new growth begins. By cutting the stems back to this height, you can encourage new growth to emerge from the base of the plant and promote a fuller, more compact shape.
It’s important to note that mahonia plants can become bare at the base over time, with the foliage mostly concentrated at the top of the plant. This can happen due to natural growth patterns or if the plant has been left unpruned for an extended period. However, by cutting back the stems as mentioned, you can rejuvenate the plant and encourage it to produce new growth lower down.
When performing the pruning, it’s a good idea to use clean, sharp pruning shears or loppers to make clean cuts. This helps minimize the risk of disease and promotes faster healing of the wounds. Additionally, it’s important to avoid cutting back mahonia plants too late in the spring, as this can remove flower buds and reduce their blooming potential for the current year.
In my personal experience, I have successfully cut back mahonia plants to the recommended 15cm (6in) height and witnessed them bounce back with vigorous new growth. This rejuvenation can help restore a more attractive appearance to the shrub and prevent it from becoming too leggy or bare at the base.
To summarize, cutting back mahonia plants to about 15cm (6in) from the ground in late winter to early spring can help restore them if they have become bare at the base. This pruning technique encourages new growth and promotes a fuller, more compact shape. Remember to use clean, sharp tools and avoid pruning too late in the spring to maintain the plant’s flowering potential.