GROWING CONCERNS: Dont be seduced by late-blooming roses
July 3, 2008 · Updated 8:13 PM
Last week, while doing the usual fall garden cleanup chores, I noticed that a David Austin rose Id planted early in the year was sprawling about like some thorny octopus, taking up way more than its share of space. Those meandering canes were covered with exquisite, soft yellow blooms, so I wasnt certain whether this was a good time to trim them back
I contacted fellow Master Gardener Maryanne Coffey, a consulting rosarian with the American Rose Society. Maryanne told me that this was indeed a very good time to trim back those wandering canes. Maryanne said that October is a good time to assess your roses and prepare them for a typically windy Northwest winter. Right now, she said, trim back any canes that may break off in the wind, but leave the main pruning job for springtime.
At the end of October, pick all the leaves off rose bushes, she advised. When covered with leaves, rose canes become sails that can break off in the wind and damage the plant. Gather and destroy fallen leaves beneath the plants. Dont compost them, as they may harbor black spot and other diseases, Maryanne cautioned.
After youve cleaned up beneath the plants, Maryanne suggests protecting the crowns with dry mulch such as cedar bark, cocoa mulch or shredded newspaper. Dont use compost or fresh sawdust, she says, as it can promote decomposition of crowns and canes.
Dont fertilize roses now, she advised. You want to encourage the plants to go into dormancy and fertilizing has the opposite effect. Allow some rosehips to form, especially on rugosas, many of which produce chubby, red or orange rosehips that will adorn your garden all season long. Rosehips also attract hungry birds to the winter garden.
In November, give your roses a good, deep watering, Maryanne said. Be sure to keep them hydrated over the winter. Then around January, treat them to a sulfur-based dormant spray. Ive found that my roses have a lot less black spot if I dormant spray them at the same time I do the peach trees.
Lastly, Maryanne reinforced her advice to allow roses to go into dormancy for the winter. Many gardeners pride themselves on roses that produce flowers in December and January. Dont be seduced into letting them bloom all winter. It saps their energy and flower production will be down in spring.
On another, but no less important, seasonal subject, I received the following inquiry from Whidbey Island gardener Jane L.:
Im writing to inquire about transplanting Japanese anemones. I am a snowbird and will be going south soon. I would appreciate knowing if I can do it now rather than wait until spring.
The rule of thumb is to transplant spring and early summer bloomers in the fall, and late summer and fall bloomers in the spring. Therefore, Id wait until you return to transplant your Japanese anemones. Right now, you should mulch them lightly to protect them from possible deep frost, and mark the area with a stake to help you find them in the spring, when little or no foliage will be visible.
Be aware that a transplanted Japanese anemone may not bloom the first year after youve moved it. It should be fine the following year. Anemones that dont bloom may need a light application of horticultural lime, as they prefer a neutral or slightly alkaline soil to our naturally acidic soil.
The adage I gave Jane, Transplant spring and early summer bloomers in the fall, and late summer and fall bloomers in the spring also applies to chrysanthemums, asters, Rudbeckia, and other late-blooming perennials. The late-bloomers have just used up a lot of energy producing flowers, so we need to give them a rest. The stress of a move may be more than they can take. Resist the urge to move them now, and youll be rewarded with better blooms next autumn.
Mariana Graham writes this biweekly column as part of her volunteer efforts as an Island County Master Gardener. E-mail her at email@example.com.