Here is the last blog post about shearing. This is going to be all you need to know about pruning different shrubs.
Weigela florida– Prune after its done flowering around June 10, Prune again around Aug 1 to promote good budset for Spring
Hydrangea macrophylla- This plant is a mystery as to when to prune. There is never a good time to prune its always the wrong time. I have stopped growing this. Its all about luck on this one. I get lucky with other stuff. Choose your luck plants carefully, or figure out what you are comfortable being frustrated with. Many a nurseryman will tell you that their plants flower great every year. They are bringing those plants out of greenhouses. The plants are kept in an artificial environment during the winter is why they flower so well. Plants grown outside in the ground are unpredictable at best. It is so easy to cut next years flower buds off. They finish blooming so late there is no chance after they are done flowering for them to regenerate new wood to become old wood to bloom on the following year. The varieties that supposedly bloom on new wood are generally disappointing because of these factors.
Lilacs- Prune a couple weeks after they have bloomed and put on some new growth and then stay off them until the following year at the same time. If you prune them even in August like most of the other deciduous plants they generally will have real big buds set that will become real big flowers the following spring. Why mess with it???
Japanese Spirea– This one is easy. At the end of the season prune this plant back half way, in other words prune it hard. During the growing season after it’s done blooming prune it back an inch or two and you will get really vibrant colored new growth followed by flowers. I have done this as many times as 4 or 5 per year. Do not be scared prune this plant hard.
For trees always try and maintain a good central leader for structural integrity. When pruning keep your cuts out of the branch collar of the plant. This is the round coarse area where the branch meets the trunk of the tree. If you keep your cuts out of this area the plant will callous over this area and heal itself.
Avoid tree trunk sealent or branch repair products. They do not work. Plants heal themselves much better than those products. The black tarry products seem to keep plants from healing themselves.
My style is production oriented, however I have landscapes I maintain where I employ what I consider a Bonsai on a large scale approach, always respect the trunk of the plant. Keep it clean and sturdy.
If you have any other questions regarding pruning that I have not covered feel free to stop in the nursery or give us a call.