In the succession of flowering times for garden shrubs, the Forsythia comes early, and perhaps because it’s such a bright (or even objectionable, depending on who you ask) shade of yellow, rose growers use it as a reminder to get out there and prune their roses. If you lack a Forsythia, you definitely use the more attractive red-flowering currant here in the Lower Mainland, and it wouldn’t much change your timing. I snapped a picture of my inherited Forsythia this week… and as you can see, I’ll never miss pruning time:
The red/pink flowers in the foreground are quince (Cydonia), another shrub you could use to get nearly the same timing – it’s probably a week behind in my garden.
The reason many rose gardeners wait until this part of spring is that it coincides with roses being ready to break dormancy. By this time, winter kill on the canes (evidenced by black tissue higher up the extremities of your roses) will be apparent, and you will probably be able to see some of the buds swelling.
How to prune them? It depends on the rose, and it depends on what you want. This is your first chance of the season to influence your rose. Cutting harder usually means that the rose will respond with a number of strong shoots from the base, and will result in more flowers this season. A lighter prune allows the rose to grow and harden more canes, and if done properly, will allow some varieties of roses to form into a better garden shrub over the long term.
You can try to use this spring pruning and fertilizing to keep your roses a preferred size in your garden, but your influence is limited. I’ll put it this way: you’ll never make a small rose grow like a large rose by fertilizing, and you’ll never make a large rose grow like a small rose with pruning.
No matter your goals, it’s good to cut out dead, diseased and congested growth. And because roses are heavy feeders, they’ll respond well to a top dress of fertilizer or compost. A moderate amount of pruning and fertilizing will always leave your roses better off, and so I don’t get too hung up on the details… not even which other plants are blooming at the time!