Pruning is an important part of plant care. Proper and timely pruning of a black-eyed Susan will help to promote new growth and keep it healthy and robust year after year. This project is relatively easy and doesn't require a lot of time. However, there are a few things you should know before starting to prune your plant.
Annuals vs. Perennials
Black-eyed Susans actually come in both annuals and perennials, so care can vary depending on which variety you have. Perennials will die in the autumn and need to be reseeded in the spring, while annuals will self-sow in preparation for the next growing season. It will be more important to prune your annuals in the interest of growth control, but pruning during the growing season will benefit both varieties and promote healthy blooms.
Deadheading Black-eyed Susans
After your black-eyed Susan blooms, some of the flowers may become faded or slightly wilted. When this happens, you should deadhead those flowers. Deadheading a flower is simply the practice of clipping a decaying bloom just below the base of the petals or pinching it off with your fingers. This will allow your black-eyed Susan to create new blooms in place of the dead ones instead of going dormant faster than it should. Old blooms, if left alone, will turn into seed heads that will eventually reseed the plant. This can lead to problems controlling growth, so it is best to deadhead anyway.
Cutting Back Black-eyed Susans
If you want to promote a shorter and bushier growth for your black-eyed Susan flowers, you can cut them back where they reach about 12 inches in height. When they reach this height, simply lop off four to six inches below the flower petals during the middle of the growing season. This will encourage bushier growth instead and encourage your vine to produce more blooms.
Pruning for Winter
You don't have to prune back black-eyed Susan for winter, but doing so will save you a lot of clean-up in the spring. You may choose to simply cut the stem of the black-eyed Susan almost all the way down to the ground for the cold months. When spring comes, the black-eyed Susan will regenerate from the soil up.
You can still leave a black-eyed Susan stalk standing for the winter, and there are some good reasons to doing so. The leftover seeds provide a good food source for non-migratory birds during the winter months. Also, in the case of annuals, if the stalk is trimmed down too soon, they will not be able to drop their seeds to resow for the spring.