Spare the Shears, Spoil the Shrub
Heavy pruning now ensures beautiful blossoms later
Forsythia announces that spring is here to stay, while butterfly bush, formally buddleia, not only blossoms with beautiful summer flowers but also attracts butterflies.
When the butterfly bush blossoms, butterflies feed on the nectar in the flowers. Yet many gardeners hesitate to plant butterfly bush as it’s an invasive species. Recently, however, plant breeders have introduced infertile clones that don’t produce viable seeds that spread like weeds.
This fast-growing plant needs to be cut back severely each late winter or early spring. The earlier you prune your butterfly bush to the ground, the sooner it will flower. It’s not too early to prune; new growth is not affected by late frosts.
Trim back each stem within inches of the ground. Severe pruning will give you fewer but stronger stems. By pruning severely, you encourage heavy stems. The best flowers are produced on strong arching stems with numerous side branches.
Allowing many stems to remain on the plant encourages numerous short, weak stems that will only produce small clusters of flowers.
If you have a large overgrown butterfly bush, cut it to the ground even if you have to use a chainsaw.
Your forsythia may need a chainsaw, too.
Forsythia may be the most abused plant grown in landscapes likely because it’s inexpensive, grows under adverse conditions and flowers. It is often sheared into a round ball or a hedge or pruned at belly height. The results after several years of such abuse are plants with naked bottoms, stems the size of your wrist and skimpy flowers that come and go within a week.
Treated well, forsythia is a beautiful shrub with long stems containing rows upon rows of bright yellow flowers that last two or more weeks. Properly pruned, it should resemble a large fountain of bright yellow flowers spreading in all directions.
It’s never too late to start pruning forsythia appropriately. If the plant has been abused and has only thick gray woody stems growing from the ground, prune as close to the ground as possible in mid to late March. Use your chainsaw.
You will lose this year’s flowers, but your reward will come next year.
In mid to late May, you’ll notice numerous shoots arising from around the cut stump and from surface roots. Allow these shoots to grow to four to five inches tall before thinning. Using your fingers, break off the weak shoots, allowing no less that two inches of space between remaining shoots.
In June, further thin weak shoots that are arching toward the ground.
By September, most of the stems should be four to six feet tall with branches aiming in all directions. You’ll see nice fat flower buds growing from the tips to nearly the bottom of each stem.
Prune weigela the same way.
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