Spring in Utah can be a little deceptive. Finding the right time to accomplish gardening tasks is very important. Since roses are the most popular flowering shrub we grow here, I would like to offer a few tips on pruning the plants.
With the recent, unseasonably warm weather, many gardeners are behind on their pruning. That panics some and other want to know if they should still manicure their plants.
Rose pruning is important as it improves the plants' appearance and health by removing dead, diseased, weak and broken wood. It controls suckers from the rootstock and promotes large, beautiful flowers.
Unpruned plants become overgrown and grow small, poor quality flowers. The accumulated dead and damaged wood makes the rose bushes unattractive. Learning how to correctly prune the different kinds of roses is a very important part of growing good, healthy attractive plants.
Start by learning a little bit of rose anatomy. While there are many different types of roses, they are divided for pruning purposes into single blooming plants and repeat blooming plants.
The type of rose dictates how and when to prune. With all roses, diseased or dead wood can be removed anytime it is found without waiting for a specific time of the year.
Single blooming plants, meaning those that only have a spring or early summer bloom, produce flowers on wood that grew the previous year. Roses that bloom continuously throughout the season will produce flowers on wood that starts growing in the spring and continues throughout the growing season.
Prune these continuously blooming bush roses (hybrid teas, grandifloras, and floribundas) in the spring before growth starts. Start by removing all dead wood. Cut the roses back to a uniform height, leaving as much good wood as possible.
Fortunately this last winter was much kinder to these kinds of roses than previous ones. There is far less winterkill than the previous winter. Prune these now even if they are starting to leaf out so they will grow and bloom better this summer.
Make cuts ¼ inch above a strong outward facing bud. It is best to leave the canes 24 to 36 inches long, but after most winters they are pruned to down to 12 inches because of winter damage.
After severe winter damage, it may not be possible to do more than keep surviving wood without regards to correct plant shaping. More severe pruning is done on hybrid teas to induce longer stem length and larger blossoms. Shorter canes produce more blossoms with shorter stems.
If you have not pruned the single blooming roses, don't fret. Prune your hardy rambler and climbing roses after flowering. Remove dead or diseased canes and take out old, weak canes right now. Do not let canes grow for more than three seasons nor allow them to get too crowded.
Prune climbing roses to make them fit the growing area. Training canes horizontally produces more flowers. Heading back long canes stimulates lateral growth for more blossoms and foliage.
Prune old-fashioned or species roses according to their bloom. Single season bloomers are pruned after they bloom. Cut long canes back a third and trim the lateral canes back a few inches.
Repeat bloomers are pruned to shape and are not cut back. Remove damaged canes or unwanted, misdirected growth and old canes as they lose vigor or become too crowded.
Treat large pruning cuts with pruning sealer to prevent borers from entering the stem. Use high quality tools including fine tooth saws, loppers and hand shears.
Summer pruning improves rose quality. Remove unwanted growth including suckers, weak or spindly shoots, and damaged canes. Cutting flowers also prunes and keeps buds developing.
While many rose books stress pruning back to a five leaflet leaf that has not been shown to be necessary on most kinds of roses.
Remove only the flowers so that the maximum leaf surface is left on newly planted roses. Don't allow seed pods or rose hips to form until time for the plants to harden for winter. Disbudding removes all side buds to allow the terminals to develop large, showy blossoms for exhibition.
Learning to correctly prune roses will reward you with more blossoms and healthier plants. That is time is well spent whether you have one plant or a hundred. Be the envy of your neighborhood with more beautiful roses this year.
Larry A. Sagers is a horticulture specialist for the Utah State University Extension Service at Thanksgiving Point.
Red Butte Garden events:
Orchid Show, April 7 (9 a.m.-7:30 p.m.) and April 8 (9 a.m.-5 p.m.) See fascinating and unique orchids from the Utah Orchid Society on display in the Orangerie. Members of the society will answer questions and offer advice about growing and caring for orchids. There will also be orchids for sale. Cost is regular garden admission, but free for members.
Spring Garden Walk, April 12, noon-1:30 p.m. Walk the garden and experience it coming to life. See Lenten roses, daffodils, crocus, anemones, witch hazel, pussy willow, magnolia and other spring beauties. Registration is required. Cost is regular garden admission, but free for members.