The tree-form hydrangeas, due to different factors, are notoriously more difficult to propagate. Tree-form hydrangeas include the PeeGee white hydrangea, the cultivar ‘Limelight,’ and several other varieties of tree hydrangea. This article will look at how to propagate tree-form hydrangeas.
Tree hydrangeas do not lend themselves to division and do not send out basal shoots. Instead, they form one or multiple trunks that remain every year and become thick and tree-like. Therefore, the plant cannot be propagated by division.
Cuttings can be taken from the late spring or summer growth of tree hydrangeas and rooted. Take the cuttings to be about three to four inches in length and from the tip of growing shoots. Make the cut right below a leaf and remove the lower leaves, but make sure there are some leaves remaining on the cutting. Insert the cutting into the material and keep moist until it roots. PeeGee hydrangea cuttings are finicky at rooting from my experience trying to root them in potting soil. However, I found that sticking them in straight peat moss, a medium plants don’t root well in, resulted in spectacular formation of roots.
Hardwood cuttings can be taken in early spring before growth starts. Keep them watered and wait until new growth shows and grows significantly. If the cutting is producing active growth, the chance is that it is successfully rooted and ready to plant. Transplant cuttings to larger pots or directly to the planting location, and nurture until established. Provide protection in the first few winters to minimize losses.
The plants can be propagated by layering if there are branches that touch or can be gently bent to touch the ground. Bury about six inches of the branch in the soil. Potting soil can be added to the area if desired. Scratching the bark just a bit can provoke the plant to root easier, and will root at leaf nodes. Cover the section of the branch with soil, and place a rock on top to keep it under the ground. Allow it to sit there through the season and winter, then remove the new plant the next spring, assuming that it has rooted successfully.
These are the ways to successfully propagate tree-form hydrangeas, and by knowing the preferences of tree hydrangeas for reproducing, you can be able to propagate them without much hassle successfully.